Central and Eastern Plains Production Handbook Elcome to the United Sorghum Produced and Edited By: Checkoff Program’S Central and Dr

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UNITED SORGHUM CHECKOFF PROGRAM Central and Eastern Plains Production Handbook elcome to the United Sorghum Produced and Edited by: Checkoff Program’s Central and Dr. Jeff Dahlberg, USCP Research Director W Earl Roemer, USCP Research Committee Chair Eastern Plains Production Handbook. We Jeff Casten, USCP Research Committee 5 Gary Kilgore, USCP Research Committee have integrated research from various James Vorderstrasse, USCP Research Committee sources to produce an easy-to-use guide Authored by: that can help farmers manage their crop Scott Staggenborg, more efficiently. Sorghum has tremendous Professor, Cropping Systems Kansas State University potential to return a profit to your farm Danny Rogers,

4 and the work of the Sorghum Checkoff Professor, Extension Agriculture Engineer-Irrigation will only improve that potential over time. Kansas State University As you manage your sorghum, keep these Curtis Thompson, Professor, Extension Weed Management tips in mind: Kansas State University • Make sure you are using the hybrid Doug Jardine, Professor, Pathology that works in your area and planting Texas AgriLife Extension Service to get the right “plants per acre” in Kraig Roozeboom, your field. Asst. Professor, Cropping Systems • Use an integrated weed management Kansas State University strategy. Jeff Whitworth, Asst. Professor, Integrated Pest Management • Most importantly, provide the crop Kansas State University with adequate fertilizer. W. Barney Gordon, Emeritus Professor, Soil Fertility and Crop Management 2 3 By following a few guidelines, you’ll be Kansas State University amazed at what this crop can do for you. Joe Harner, We strive to help you make sorghum Professor, Livestock Systems Kansas State University more profitable for your operation. But Randy Taylor, remember, every situation is a bit different Professor, Extension Machinery Specialist so contact your local county extension Oklahoma State University office, land-grant university or other area Funded by: sorghum farmers to help you get the United Sorghum Checkoff Program most out of this water-sipping crop.

4201 N. Interstate 27 Lubbock, TX 79403 Chair, United Sorghum Checkoff Program Board 806-687-8727

0 1 www.sorghumcheckoff.com Sorghum Farmer, Prairie View, Kan. Growth Stages |5 Contents Growth Stages Topic Page Growth Stages 5 It is important to understand the various develop- mental stages of sorghum since this understanding Hybrid Selection 15 will assist in making irrigation and management decisions. The stages are based on key points of Planting 22 sorghum growth that are used to describe sorghum from planting to maturity. Irrigation 31 Another common scale that is used among Fertilizer Requirements 37 sorghum researchers is a more simplified growth scale. (Fig.1) GS1 would equate to stages 0-5 in Weed Control 52 this system. GS2 would represent from stages 5-10, and finally, GS3 would be from stage 10 to 11.5. Insect Management 79

Diseases 88 Comprehensive grain sorghum growth and development guides are available, such as Kansas Harvesting 97 State’s “How a Sorghum Plant Develops” (http:// www.oznet.ksu.edu, currently being revised Sorghum Economics 102 with your sorghum checkoff dollars) and Texas AgriLife’s “How a Sorghum Plant Grows,” (http:// References 105 agrilifebookstore.org). Either of these guides provides pictures of different growth stages, Calculations & Conversions 106 graphs of cumulative nutrient uptake relative to growth stages (KSU), or approximate heat unit Appendices requirements (base temperature 500F, maximum a. The Sorghum Plant 113 1000F) for attaining a particular growth stage b. Photos 116 (Texas AgriLife).

Notes 122 Refer to Appendix A, page 113, for more information about the sorghum plant. © Copyright 2010 6 | Growth Stages Growth Stages |7 Fig. 1. Stages of sorghum growth: Stage 0: 0.0 planting; 0.1 start of imbibition; 0.5 radicle emergence from seed from (caryopsis); emergence 0.5 radicle imbibition; 0.1 start of 0: 0.0 planting; Stage growth: sorghum of Fig. 1. Stages 3: Stage leaf visible; 2: first Stage 1: emergence; Stage tip; coleoptile seed from at (caryopsis); 0.9 leaf emergence 0.7 coleoptile of main start shoot and 5.1 tillering; differentiation Panicle 5: Stage visible; sheath 4: fifth leaf Stage visible; sheath leaf third leaf visible, 7: flag Stage stage); vegetative (late elongation tiller; several 6: stem one and tillers; Stage shoot and 5.9 main anthesis 10: Stage emergence; inflorescence showing, just 9: panicle Stage stage); vegetative 8: bootingof (end Stage whorl; at late 11.3 grains stage; dough at early 11.2 at milkgrains stage; 11.1 maturity; 11: grains Stage flowering); panicle (50% of (seed grain 11.5 mature 30% seed moisture); approximately layer, (black maturity physiological at 11.4 grains stage; dough 65. A, page Appendix see information more For 15%). (Courtesy K. Cardwell). approximately moisture 8 | Growth Stages Growth Stages |9

A summary of sorghum growth and development Growing point differentiation (GPD) is outlined below including: This key growth stage and its importance are • Key growth stages largely unrecognized and unappreciated by pro- • In-season management suggestions (fertility, ducers. The stage occurs approximately 30 to 35 post-emerge herbicide applications, irrigation) days after emergence, perhaps a few days longer • In-season insect activity, their potential for full-season hybrids, and sooner for early effect on the crop, and scouting timing maturity hybrids. It generally corresponds with suggestions the 7 to 8 leaf stage. Sorghum can tolerate signifi- Growth Stages Description and Management Tips cant stress from drought, hail, and even freezing Emergence Coleoptile visible at soil surface. Coleop- temperatures prior to this stage, however, stress tile is the first leaf and is shorter than the at this stage can significantly impact yield. later emerging leaves and has a rounded Growing point is now above the soil surface, and tip (leaf #1). the plant is approximately 12 to 15 inches tall. The plant may have lost one to three leaves from 3-Leaf Collar of third leaf is visible (once a leaf’s the bottom of the plant and is entering a period collar forms the leaf no longer expands). of rapid growth. This stage occurs approximately 10 days after emergence, depending on soil The maximum potential number of spikelets temperature, moisture, planting depth, and seeds per spikelet is a major component of etc. Slow emergence may lead to more maximum yield potential and are determined injury from pre-emerge herbicides. Insects: over a period of seven to 10 days. Corn leaf aphids may infest the whorl and greenbugs may infest the leaves although Management: When applying mid season not likely. nitrogen in one application, ideally the N should 4-Leaf Collar of fourth leaf is visible approxi- be available in the root zone by GPD, and mately 15 days after emergence. irrigation, if available, is recommended to ensure that the growing point is not subject to moisture stress during GPD. Both good fertility and moisture enhance GPD and the subsequent yield potential. Dryland producers can enhance GPD by applying N early and ensuring that plant population is modest so that each plant has sufficient moisture for good spikelet and seed set. 10 | Growth Stages Growth Stages |11

A note about brace roots, sorghum standability 20% of N past GPD, the final N should be applied and possible cultivation: Brace roots are key to within 60 days of planting or mid-boot, which- sorghum’s standability. If it appears brace roots ever comes first. are having trouble entering the soil (likely more Insect: Corn leaf aphids begin to decrease. common for sorghum planted on top of beds Greenbugs may be approaching an economic where the soil is hotter and drier), then cultiva- threshold. tion may be needed to move soil around the base of the plant. If this must be done, ensure that any Heading pruning of the expanding root system is mini- • 50% of the plants in the field have visible mized after 30 days. heads. Insects: Greenbugs may be at economic thresh- Flag leaf visible old levels. • Tips of the flag leaf ( last leaf, comma which will be smaller) visible in the whorl. Flowering • The last three to four leaves may not be fully • Occurs when 50% of the plants are in some expanded. stage of bloom. Insects: Greenbug population may begin to • A plant is considered to be flowering when rapidly increase. bloom progresses half way down the head. • Peduncle is rapidly elongating. Boot • Flowering occurs over a four to nine day • Leaf collars of all leaves now visible. period. • Sorghum head is enclosed in the flag leaf • Stress or herbicide drift can lead to blasted sheath. heads. • Potential head size has been determined closer Insects: Greenbugs may continue as a problem, to GPD. and mummies may be present. Begin check- • Peduncle is beginning to elongate. ing for headworms. Sorghum midge potential • Stress at this time will reduce the length of the should be evaluated. For the South Plains and peduncle. the northern Rolling Plains, sorghum flowering Management: Maximum water use occurs at by August 1 will most likely escape significant this stage. Crop will respond very favorably to midge damage potential, but a June 30 flowering irrigation at this stage. Historically, this stage is needed in the Concho Valley and lower Rolling of growth is the optimum time to apply limited Plains to minimize midge potential. irrigation if crop is stressed. If you delay up to 12 | Growth Stages Growth Stages |13

Soft dough black layer and grain moisture are less than 30%. • Grain can be easily squeezed between the Modified from ‘Sorghum development and key growth stages.’ fingers. Brent Bean, Extension Agronomist, and Carl Patrick, Exten- • Eight to 12 functional leaves remain. sion Entomologist (retired), Texas AgriLife Extension Service, • One half of grain dry weight has accumulated. Amarillo. • An early freeze will result in shriveled light grain. Determining Leaf Stage • Susceptible to bird damage. Grain sorghum is numbered by the fully-sized Insect: Greenbugs may continue as a problem. leaves that have a developed collar. If the seventh Mummies should be increasing. Continue to leaf (rounded coleoptile leaf is number one) has check for headworms. a collar, even though two to three other newer leaves may be visible, the plant is at leaf stage 7. Hard dough Some herbicide labels cite leaf stage for timing, • Cannot squeeze grain between the fingers. usually a limitation of further herbicide applica- • Three-fourths of grain dry weight has accumu- tions. The lower leaves may be crumbling and lated. even missing, but by counting back from the last • Water stress during grain fill may cause lodg- fully formed collar as leaves alternate from one ing. side of the plant to the other, one can usually Insect: Greenbugs and headworms should be on determine leaf stage, at least within one leaf. the decline. Sorghum Yield Components Black layer Sorghum yield is based on three factors: number • Dark spot appears on the tip of the kernel. of heads, head size, which includes the number of • Maximum total dry weight is achieved. seeds, seed size, and test weight. Although these • Depending on the heat, an individual seed factors may compensate for each other, for both from flower to black layer is typically 30 to 35 irrigated and dryland production, the number days, but could stretch to 40 days or more in of seeds per head is the greatest component of prolonged cool fall conditions. yield. This does not mean that having as many • Sorghum maturation slows significantly once seeds as possible per acre gives the best yields. nighttime temperatures drop below 45°F. Individual heads have the best yield potential for • Grain is 25 to 35 % moisture. the environment with high fertility and adequate Management: If harvest aids are used, label moisture per head, even if there are not a lot of guidelines target application no sooner than heads. 14 | Growth Stages Hybrid Selection | 15

Tillering is often left out of the discussion on yield potential, and its expression can signifi- Hybrid Selection cantly enhance yield in many instances, but tiller- Selection of appropriate hybrids is foundational ing may actually limit yield when drought stress for successful grain sorghum production. It is not is significant, diminishing the size and yield unusual for the best hybrid to out-yield the poor- potential of the primary head. For this reason, est hybrid on a test or farm plot by 40 bushels or reduced tillering hybrids have often performed more per acre. Even on a multiyear-test-average better in West Texas dryland. basis, hybrid yields may differ by more than 20 bushels. Freeze Damage & Hail Injury Grain sorghum is occasionally hit by a late freeze Although yield components such as number of that may damage leaves, but sorghum may heads per acre, number of seeds per head, and face hail damage in the spring and early sum- seed weight are important for determining yield, mer. Early freeze injury often has little effect on they tend to compensate for each other. Any one sorghum as the growing point remains below the or specific combinations of these components soil surface for several weeks after germination. is too inconsistent to serve as a reliable yield Early hail-damaged sorghum has surprisingly predictor. Maturity, standability (stalk strength), little loss in yield potential provided the plants and pest resistance are the major characteristics remain healthy. For example, a 50% leaf removal affecting hybrid performance in the Central and five weeks after germination (near growing point Eastern Plains. differentiation) reduces yield potential about 5%. Losses are substantially higher for older plants. Maturity. A good full-season hybrid will almost always out-yield a good early-season hybrid, For further information on these conditions other conditions being equal and favorable consult Texas AgriLife Extension’s “Assessing Hail for sorghum growth. The stalks of full-season and Freeze Damage to Field Corn and Sorghum,” hybrids tend to be larger and stand better than B-6014 (http://agrilifebookstore.org, or your those of earlier hybrids. The rule of thumb is to county Extension office). plant the latest-maturing hybrid available within the limitations of projected moisture availability, average length of growing season, and crop sequence. Hybrid selection can then be narrowed to that group of hybrids meeting the maturity criteria. 16 | Hybrid Selection Hybrid Selection | 17

Maturity is relative in a region that varies from and environmental stress is important in hybrid 800 to 1,800 feet in elevation and from nearly 40 selection. Planting two or more hybrids that to less than 25 inches of annual precipitation. A differ slightly in maturity will help ensure adverse conservative view is that hybrids should be in the environmental conditions will not affect total maturity class reaching physiological maturity grain sorghum production. (black layer or maximum dry-matter content of grain at about 30 to 40% moisture) a week or Crop rotations and sequencing can influence two before the average date of the first killing hybrid choice as well. Producers wishing to plant frost. To assure adequate time to mature before wheat in the fall after a sorghum crop should frost, select and plant sorghum hybrids so they select hybrids that will mature early enough to bloom by early to mid-August in south-central allow timely sorghum harvest and wheat plant- and southeast Nebraska and by late August or ing. Early maturing hybrids combined with early September in north-central and northeast chemical desiccants (e.g. glyphosate, diquat) Oklahoma. applied after physiological maturity (black layer) can speed dry down and move up harvest, In the Central and Eastern Plains, the optimum increasing the probability of success for the fol- hybrid maturity varies with soil depth and lowing wheat crop. texture, growing season, planting date, and precipitation distribution. In the Eastern Plains Standability. If a hybrid lodges after having stood with deep soils and low probability of an early well in previous years, producers may wonder fall frost, fuller-season hybrids can be planted what happened. The timing of moisture exhaus- through June. If planting is later than early June tion in relation to the plants’ growth stage is a in the central plains, earlier maturing hybrids prime source of lodging variability. Post-flower- should be selected. On shallow soils, moisture ing drought stress not only reduces yield, but also exhaustion can be more damaging to late hybrids increases susceptibility to invasion by organisms, than frost. Earlier hybrids should be planted on such as charcoal rot, that cause lodging. those sites. Moisture stress often causes lodging problems because of incomplete development of In any maturity group—early, medium or late— stalk-strengthening tissue, invasion by organ- there are hybrids that consistently lodge worse isms that further weaken stalk tissue, or both. than others. They should be avoided, especially By choosing hybrids that mature early enough on fields with a history of frequent lodging. The to avoid severe moisture stress, lodging risk may best sources of information are seed companies, be reduced. The interaction of hybrid maturity performance-test results, personal experiences, 18 | Hybrid Selection Hybrid Selection | 19 and extension agents. Be sure to look at lodg- control generally was needed only for heavy ing notes from several trials before deciding if a seedling infestations and for large, persistent hybrid is more or less prone to lodge. greenbug populations in later plant-growth stages. Unfortunately, those hybrids had little Disease and Insect Resistance. Diseases and or no resistance to greenbug Biotype E when insects often are destructive in specific loca- it appeared, so insecticides were the primary tions and sometimes cause widespread damage. control method until adapted resistant hybrids When selecting hybrids, pest resistance should be became available a few years later. More recent considered on the basis of probability of a repeat strains, biotypes I and K, have added additional problem, availability of resistance or tolerance in dimensions to the greenbug-resistance picture. commercially available hybrids, practicality of chemical control, and use of hybrids best adapted Historically chinch bugs have been a concern to management practices that have been adjusted in the northern and eastern parts of the Central to avoid or tolerate pest problems. and Eastern Plains region. Some hybrids appear to have more tolerance to chinch bugs than Hybrid differences in susceptibility have been others, but insecticides are the major control documented for sooty stripe, fusarium stalk rot, method. The use of systemic insecticides in charcoal rot, viral diseases (maize swarf mosaic the furrow at planting or as seed treatments, virus and sugarcane mosaic virus), northern corn planting earlier or later than normal, and avoid- leaf blight, rust, downy mildew, head smut and ing planting sorghum next to small grains can others. The importance of resistance to various reduce the probability of chinch bug damage to diseases depends on the cropping system and sorghum seedlings. The latest generation of sys- grower practices. For example, no-till cropping temic, insecticidal seed treatments have proven systems increase the probability of some diseases to be quite effective in preventing early-season such as sooty stripe, especially if sorghum residue damage from chinch bugs. remains from previous crops. Fungicidal seed treatments may adequately control sorghum Head Exertion. Many companies rate hybrids downy mildew in some cases. for head exertion – the extent to which the head emerges from the boot, especially under Greenbug populations have shifted over the moisture-limiting conditions. In some hybrids, years making hybrid tolerance traits obsolete the peduncle may not elongate enough to fully over time. Good greenbug-tolerant hybrids expose the head when soil moisture is limiting were available from 1976 to 1980, and chemical during heading. With poor head exertion, the 20 | Hybrid Selection Hybrid Selection | 21 portion of the head still wrapped in the sheath of interest. Avoid reliance on only one source of of the flag leaf can have poor seed set or may be hybrid-performance information. Use results more susceptible to grain molds if rains come from company tests, county strip trials, and after pollination and grain fill. While it is prefer- university performance tests to select a small set able to have fully exposed heads to maximize of hybrids to try on your farm. yield, the negative effects of incomplete head • Try this subset of hybrids on a small scale and exertion are more pronounced in some hybrids keep harvest records. This is becoming easier than in others. every year with the widespread use of guidance/ auto-steer technology and yield monitors. Be sure Seed and Plant Color. Producers often prefer to replicate comparisons in such a way that you hybrids with a certain seed color based on their can be confident of your conclusions. opinion of how well seedlings emerge in stress- • Plant two or more hybrids of differing matu- ful conditions. Although laboratory studies have rity to spread out risk from adverse weather documented greater stress germination and conditions. elongation for seedlings with the purple plant • Keep alert for hybrids with resistance to pests characteristic, no differences in these measures threatening the next crop. New strains of pests, of seed vigor were attributed to seed color. Field such as greenbugs and maize dwarf mosaic virus, studies have shown greater seedling emergence appear from time to time, so it is important to for red seed than for white seed, but the white keep up with new developments in both pests seeded types had greater yields. Adequate and hybrids. emergence and high yields have been exhibited by hybrids of all seed and plant color combinations. Specific hybrid and seed lot performance are probably more important than seed or plant color. Select hybrids with above-average seedling vigor when planting early or in no-till systems.

Summary. The surest way to select hybrids that will perform well on your farm is to: • Spend sufficient time searching for improved hybrids. • Look at hybrids from several companies. • Look at a broad base of information on hybrids 22 | Planting Planting | 23

water erosion is the primary concern, leaving 30 Planting % residue cover after planting reduces soil loss to acceptable levels. The actual level of residue Grain sorghum needs a warm, moist soil well required to minimize soil loss will vary with supplied with air and fine enough to provide each field. Conservation tillage alone may not good seed-soil contact for rapid germination. A adequately protect the soil from erosion. In these number of different tillage and planting systems situations, conservation tillage can be integrated can be used to achieve these conditions. These with other practices—such as terracing, contour- systems may involve primary or secondary tillage ing, strip cropping, and windbreaks—to provide or no tillage operations prior to planting. Seed- erosion protection. Long-term research in Kansas bed preparation should provide a means of prof- has shown grain sorghum can be grown success- itable crop production while minimizing soil ero- fully in conservation- tillage systems, but uni- sion due to wind and water. Conservation tillage form residue distribution, effective weed control, systems (e.g. reduced-till, mulch-till, ecofallow, proper seed placement, correct planter adjust- strip-till, ridge-till, zero-till and no-till) provide ment, soil testing, and fertilizer management are erosion protection, These systems also provide important for success. the additional benefits of moisture, energy, labor, and even equipment conservation. Crop sequencing and rotation becomes increas- ingly important in systems with little or no An ideal sorghum production system should tillage and greater amounts of surface residue provide the following at planting: cover. Long-term research at Manhattan, Kan., • Weed-free conditions documents the importance of rotation in no-till cropping systems, showing a 16 bushel per acre • Conserve moisture advantage for rotated sorghum compared with continuous sorghum in no-till (Table 1). Results • Preserve or improve soil tilth from long-term studies at Belleville, Kan., and • Reduce wind and water erosion Mead, Neb., lead to the conclusion that sorghum rotated with soybeans almost always yields more • Result in adequate stand establishment. than continuous sorghum, regardless of how Tillage and Rotations. The amount of residue much nitrogen fertilizer was applied. A four-year necessary for erosion protection depends on no-till study at Hesston, Kan., documented that several factors, such as climate, soil erodibility, sorghum after wheat produced 12 bushels per surface roughness, field length, slope length and acre more than sorghum after sorghum (Table steepness, cropping practices and conservation 1). Sorghum after soybean produced 10 bushels practices. Generally, in the Eastern Plains where per acre more than after sorghum. Sorghum after 24 | Planting Planting | 25 double-crop sorghum yielded about the same as moderately and well-drained soils. Soils often continuous sorghum. remain cooler and wetter through the growing season under no-till conditions. This is particu- No-till grain sorghum planting is best suited to larly true in heavy residue. While wetter soils are an advantage during dry periods, at planting time they can mean slower germination, delayed maturity and a longer period when seeds and seedlings are susceptible to pests. These condi-

Hesston tions can result in reduced yields in no-till situ- No-Till 91 100 103 100 89 ations, particularly in cool, wet springs and on poorly drained soils. Other conservation-tillage systems, such as reduced-till or strip-till, may be better choices in those situations. No-Till 99 83 Planting Practices Row width. Most grain sorghum is planted in 30-inch rows because other row crops have Reduced Tillage 89 85 performed well at that row spacing Historically, 30-inch rows performed better than wider rows, Manhattan and narrower rows have not consistently yielded better than 30-inch rows. Results from nearly 20 studies comparing row spacings can be grouped into three categories: 1. Greater yields with narrow rows (10, 15 or 20 Conventional Tillage Conventional 87 ------bu/acre------85 inches vs. 30 inches). This response was observed in about half of the studies, all of which were in environments that had yields greater than 110 bushels per acre. 2. Greater yields with wider rows (30 inches). This response was seen in about a quarter of the Table 1. Grain Sorghum Yields as Affected by Tillage System and TillageSystem by as Affected Sorghum Yields 1. Grain Table Locations Central in Eastern and Kansas Two at Previous Crop Previous Crop Previous Soybean Wheat Double-Crop Soybean Double-Crop Sorghum Sorghum studies, all of which were in environments with yields of 100 bushels per acre or less. 3. No response to row spacing. This response was 26 | Planting Planting | 27 affectingyields. growingdepending on expected conditions without significantly 1 Table 2. Grain Sorghum Recommended Plant Spacing and Seed 15-inch rows Population 30-inch rows observed in about a quarter of the studies, most Populations may increased or by be decreased 25% from values, these often in high-yielding environments. An advantage of narrow rows is that plants shade the soil quicker, improving weed control and 7.8 field emergence Within-row spacing at seed planting assuming 65% 35,000 3.7 reducing soil erosion. 23-26 Seeding rate. Seeding rates or plant populations vary depending on rainfall and growing condi- Average annual (inches) rainfall 6.0 45,000 3.0 tions. In Table 2, recommended plant popula- 26-32 tions are given for specific rainfall regimes. When seeding in narrow rows in high-yielding Plants acre per environments, populations that are 25 to 30% 3.9 70,000 1.9 higher than these recommendations may be able >32 to capture slightly higher yields. Higher seeding rates also should be used with later planting dates 1 because sorghum plants tend to produce fewer 2.7 100,000 1.4 productive tillers with warmer temperatures dur- Irrigated ing the vegetative growth stages. Two formulas can be used in calculating plant populations and seeding rates: Hybrid seed size varies, so planting in terms of pounds of seed per acre results in large differences in plant population and wastes money. Although there may be emergence differences Formula 1. Plant population or seeding rate due to seed size, generally no yield differences are seeds or found. 43,560 sq. ft. 12 in. plants X X acre row spacing foot-row Sorghum plants may tiller and compensate for (in.) thin stands. Large heads (more seeds per head) can compensate for thin stands. Heads produced Example 1. 43,560 sq. ft. 12 in. 3 plants by late tillers may be immature when the head =52,272 plants X X on the main stem is mature, resulting in harvest acre 30 in. foot-row per acre and storage problems. Seed weight can compensate for reduced seed number to a limited extent. 28 | Planting Planting | 29

tion and emergence occur when the soil tempera- Formula 2. Seeds or plants per foot-row ture is 70°F. Planting too early results in delayed seeding rate or plant emergence and reduced stands. Plants from early production row spacing (in.) X plantings may be taller and more vegetative than 43,560 sq. ft./acre 12 in. later plantings. Late plantings may not allow the crop enough time to mature before a damaging Example 2. fall freeze. Use earlier-maturing hybrids if plant- 70,000 seeds or plants 30 in. ing is delayed into late June or July. =4 seeds or plants X 43,560 sq. ft./acre 12 in. per foot-row Seeding depth. The optimum planting depth differs with soil types and moisture conditions. In heavier soils, a planting depth of 1 inch is High plant populations result in fewer tillers, and satisfactory. In sandy soils, seeds can be placed are necessary under irrigation and in higher- 2 inches deep without problems. Sorghum seeds rainfall areas. Excessive stands produce plants can emerge from plantings deeper than 2 inches, with smaller stems that are more susceptible to but seedlings are slow to emerge, and final stand moisture stress and lodging. numbers may be reduced. The seed should be Non-uniform stands and replanting. Results well covered with soil for excellent seed-soil from studies examining the effect of within-row contact to aid germination. Planting into soils gaps in various patterns and frequencies indicate that are too wet can result in sidewall compac- that sorghum yields are not reduced unless gaps tion, which can inhibit early root growth or poor are at least 9 feet long or a sufficient number of closure of the seed furrow, which can reduce 3-foot to 6-foot gaps reduce stands by 30% or germination and emergence. more. Compensation occurs by increases in the number of heads per plant and the number of seeds per head in neighboring plants both within a non-uniform row and in adjacent rows. Planting date. There is a wide range in planting dates for grain sorghum. Planting should be timed so flowering avoids the hottest, driest period of summer. Suggested planting dates are given in Figure 1. Utilizing several planting dates is suggested to spread the risk of one planting date flowering during a stress period. Quick germina- 30 | Planting Irrigation |31 Figure 1. Suggested Grain Sorghum Planting Dates Irrigation Area Dates Zone 1 May 15 to June 20 Grain sorghum has a drought-tolerant reputa- tion; therefore, it is a viable crop choice for some Zone 2 May 10 to June 25 irrigators with low-capacity wells and limited Zone 3 May 1 to June 25 water because a good yield response to lim- Zone 4 April 20 to May 10, June 5 ited water applications are possible. However to June 30 under full irrigation, corn generally becomes the preferred feed-grain crop due to its ability to produce more grain per unit of added water in high-yield situations. The average yield of grain sorghum has increased over time with irrigated yield increasing at about 0.6 bushels per acre per

Zone 2 Zone year since 1974. Zone 4 Zone Water-use Requirements. Grain sorghum will use about 18 to 22 inches of water to produce a normal yield. The total amount of irrigation water needed depends on the season and the amount of soil water stored in the root zone. Dry-year-irrigation estimates (NRCS Irrigation Guide) for grain sorghum range from about 15 inches in western growing regions to less than 7 inches in eastern growing regions. Irrigation estimates for years with average rainfall are from about 13 inches in the west to 4 inches in the Zone 3 Zone east. These range estimates are for well-watered conditions. Grain sorghum is generally one of the later-plant-

Zone 1 Zone ed summer crops. This allows for the soil profile to accumulate water prior to planting and often means the reproductive stage begins after the hottest weather of the summer passes. Water-use 32 | Irrigation Irrigation |33 rates for the various growth stages are shown in high-water-holding-capacity soils, like medium- Figure 2. Average peak water-use rates are about textured silt loams or heavier clay loams, limited 0.3 inch per day, although occasionally a single- water applications during the growing season of day peak use might approach 0.5 inch per day, about half the full irrigation requirement for well similar to the peak use rate of any field crop at watered conditions (6 to 8 inches) will often pro- full cover and active growing conditions. duce 80 to 90% of the full yield potential under most circumstances. Grain sorghum develops an extensive root system, which can extend to 6 feet in a friable soil. On deep, silt loam soils, one or two relatively Irrigation scheduling usually accounts for only large irrigation applications (4 to 6 inches), can the upper 3 feet of the root zone since most of the produce near-maximum yields compared to water extraction will occur in this region. About three or four in-season irrigations. Timing those 75% of water use will occur in the upper half of irrigations during periods of peak demand will maximize yield and water use efficiency (Table 4). the root zone. Under stress conditions, when the Although pre-plant irrigation can be effective on upper zone becomes water-limited, the crop will deep soils, it is not recommended if any in-sea- use water from significant soil depth (Table 3). son irrigation is planned. In most years, sufficient Irrigation Management. In addition to being rainfall is available to recharge the upper root able to extract water from a great depth within zone, making pre-plant irrigation an inefficient the root zone (Table 3), grain sorghum is able water-use practice. to extract soil water at a lower percentage of Full and limited irrigation of grain sorghum on available soil water without yield loss when water sandy soils require more frequent and smaller is limited in the upper root zone. The general irrigation applications, which matches the capa- irrigation-management recommendation is to bility of center-pivot systems commonly used to maintain soil water at or greater than 50% avail- irrigate sandy soils. Irrigation scheduling using able water. For grain sorghum, however, the soil evapotranspiration or by maintaining a given water can be depleted to an average of 30 to 40% soil-water-depletion balance may be most useful available water before grain yields are severely re- in this condition where low-water-holding capac- duced. Scheduling based on soil-water depletion ity and restricted root zones present challenges or crop-water use (evapotranspiration or “ET”) to irrigation management. Under-irrigation can rates would be recommended when full irriga- quickly result in yield-limiting stress. A single, tion of grain sorghum is intended. large irrigation can result in nutrient leaching Grain sorghum is a crop that lends itself to a and inefficient water use due to deep percolation. limited irrigation-scheduling program. For 34 | Irrigation Irrigation |35

If water becomes limited at any stage of growth, grain sorghum has the ability to tolerate water stress. Within certain limits, grain sorghum is a drought-resistant crop. One difficulty with a soil- water shortage is a delay in maturity. If plant maturity is delayed due to water stress, the crop may face frost damage in the event of an early freeze.

Late-season water stress during grain filling can Figure 2. Characteristic water-use pattern of grain sorghum result in shriveled seeds, which reduces yield. Irrigation Summary • Grain sorghum’s water-use rate is similar to other summer crops and peaks at about 0.3 inch per day. The peak use begins at approximately initiation of the reproductive stage. • The typical seasonal water need is 18 to 22 inches. • Irrigation requirements vary from less than 6 inches in the east to about 15 inches in the west under well-watered conditions in normal years. • Grain sorghum has an extensive root system, and its drought tolerance makes it suitable for limited irrigation. 36 | Irrigation Fertilizer Requirements | 37 Fertilizer Table 3. Water-Extraction Patterns Under Different Soil- Water Conditions, Garden City, Kan. Requirements Depth Normal Moderate Moderate to (feet) (no stress) stress severe stress Grain sorghum is grown throughout the Central 0-1 31.4% 25.3 7.5 and Eastern Plains under a wide range of climatic 1-2 23.2 18.9 7.3 conditions. Sorghum is considered very efficient in utilizing nutrients from the soil because of 2-3 18.4 19.9 14.8 a large fibrous root system; however, profitable 3-4 13.4 17.9 24.9 responses to fertilization can be expected on 4-5 7.6 11.7 24.4 many soils. Total nutrient uptake by sorghum is 5-6 6.0 6.3 21.0 similar to that of corn and wheat at comparable Source: Technical Bulletin 113 yields. Table 6 shows that harvesting only the grain removes considerably less nutrients than if the entire crop is harvested for silage or forage. Table 4. Grain Sorghum Yield Response to Limited Irrigation and Timing, Scandia, Kan. Fertilizer and lime needs can best be determined Irrigation Frequency and Timing Yield (bushels/acre) by soil tests with supporting experience and No Irrigation 111 field-history information. However, soil tests are Irrigation at Boot 136 no better than the sample collected in the field. Irrigation at Boot + Grain Fill 145 Interpretations of soil tests and resulting fertilization recommendations are made based on many years of research. Fertilizer rates are targeted for optimum yields assuming yield potential is not restricted by other growth-limiting factors.

Nitrogen. Nitrogen is the element most frequently lacking for optimum sorghum production. Nitrogen recommendations will vary with expected yield, soil texture and cropping sequence.

A soil test for available nitrogen in the soil 38 | Fertilizer Requirements Fertilizer Requirements | 39 profile is encouraged where nitrogen or manure N Rec= (Yield Goal x 1.6)-SOM x 20)-Profile N-Manure applications have been excessive relative to N-Other N Adjustments + Previous Crop Adjustments yields. The profile nitrogen soil test is used to Where: reduce nitrogen application so accumulated available nitrogen is utilized. Consult your soil • N Rec: nitrogen recommended in lbs. per acre testing laboratory for instructions on proper soil • Yield goal: a realistic yield goal in bushels per year sampling and handling. Samples should be taken • % SOM: percent Soil Organic Matter to a depth of 2 feet and must be air-dried after •Profile N Test: lb. N.acre= 0.3 x Sampling Depth collection to minimize mineralization in han- (inches) x ppm Profile Nitrate-N (2 foot sampling dling and shipping. depth.) Default value of 30 lb. N/acre if sample not taken. Another important consideration in determining • Manure n: previous year's manure (50 lbs. for last the optimum nitrogen rate is cropping sequence. year, 20 lbs. for two years ago, and zero for no Research in the Central and Eastern Plains shows manure history) nitrogen credits for legumes grown in rotation • Previous Crop Adjustment: Use Table 7 for previous with sorghum can be substantial. Table 7 summa- legumes, 20 lbs. for fallow (if no profile N test) rizes nitrogen credits for legumes in rotation with and zero for all other previous crops. sorghum and the basic nitrogen recommendation adjustment for these credits. Figure 1 shows the Field comparisons of nitrogen sources indicate value of including a legume in a rotation. When little agronomic difference between sources no nitrogen was applied, grain sorghum grown in when properly applied. For no-till or reduced- annual rotation with soybean yielded 29 bush- till systems that leave almost a complete residue els per acre greater than continuous sorghum. cover, materials containing urea should be When averaged over all applied N-rates, rotated injected below the residue to minimize volatiliza- sorghum yielded 19 bushels per acre greater than tion and immobilization losses. If urea or urea continuous sorghum. Continuous sorghum yield containing N-fertilizer is surface applied and continued to increase with increasing N rate not incorporated by tillage or does not receive up to 90 lbs. per acre, whereas yield of rotated one-half inch of rainfall or irrigation within sorghum was maximized with application of 60 24 hours, there is potential for ammonia loss. lbs. N per acre. Enough ammonia loss to reduce crop yields can sometimes occur when urea or UAN is applied Nitrogen recommendations can be calculated by to a warm and moist soil heavily covered with using these factors: crop residue. Source selection should be based on 40 | Fertilizer Requirements Fertilizer Requirements | 41 cost (applied), availability, adaptability to farm Application of nitrogen through the irrigation operation, and dealer services. Nitrogen applica- system has been quite satisfactory on sandy tion for grain sorghum can be made at various soils. Application of nitrogen through irrigation times with equal results on most soils. Nitrogen systems under other soil conditions is possible, utilization is quite rapid after the plants reach the but the fertilizer distribution is no better than five-leaf stage. By boot stage, 65 to 70% of the the water distribution. No nitrogen material that total nitrogen has been taken into the plant. contains free ammonia should be used when applying through a sprinkler system unless Nitrogen applications should be timed so special precautions are taken. A small amount of nitrogen is available when needed for this rapid nitrogen also may be applied in starter fertilizer. growth. Pre-plant nitrogen applications can be made in late fall or spring (except on sandy soils) Phosphorus. Phosphorus application should with little concern for leaching loss. On sandy be based on a soil test. Consistent responses soils, pre-plant nitrogen applications should be to phosphorus fertilization have generally delayed until spring, sidedressed or split with occurred on soils testing very low or low in part in the spring and part sidedressed. If nitro- available phosphorus where yield potential is not gen is applied sidedress, the applications should restricted by low rainfall. With medium-testing be made by shortly after the five-leaf stage. soils, responses have been erratic and normally quite small. Phosphorus applications are rec- Active optical sensing systems have been shown ommended on medium-testing soils for their to be useful in measuring crop biomass early in potential yield response and to maintain the soil the growing season and using that measurement in a highly productive condition. Phosphorus to predict final yield. Coupled with a well fertil- recommendations are shown in Table 8. ized reference strip and an unfertilized check strip, to provide an estimate of the soils nitro- Phosphorus can be applied preplant-broadcast, gen supply to the crop sensors may provide an preplant-knifed, or banded at seeding. If a dif- accurate nitrogen recommendation. The sensor ference among methods is found, broadcast is technology seems to work best 35 to 45 days after normally inferior. Starter applications are most planting; however this provides only a narrow efficient when small amounts are applied on soils low in available phosphorus. Starter applications window of opportunity to fertilize the crop. Pro- can be placed in direct contact with the seed or ducers may want to apply a base level of nitrogen placed to the side and below the seed. If placed on sorghum at planting to ensure optimum yield. in contact, the starter material should contain no more than 10 lbs. of nitrogen plus potash per 42 | Fertilizer Requirements Fertilizer Requirements | 43

acre. The nitrogen and potash can cause germina- $750 0.46 0.82 1.17 tion damage with their high salt index. No urea or ammonium thiosulfate should be placed in $700 0.43 0.76 1.09 direct seed contact. $650 0.40 0.71 1.02 Preplant applications can be made in the fall or spring and should be thoroughly incorporated $600 0.37 0.65 0.94 because phosphorus does not move appreciably in the soil. With no-till or reduced-till seedbed $550 0.34 0.60 0.86 preparation, preplant-knifed or banded at seeding are preferred over broadcast. $500 0.30 0.54 0.78

Cost per Ton Liquids, solids, and varying chemical forms of $450 0.27 0.49 0.70 phosphorus (ortho- and polyphosphates) are available. Research indicates that, in general, all $400 0.24 0.43 0.63 are agronomically equal. Selection of a phosphorus source should be made on the basis of cost, $350 0.21 0.38 0.55 availability, and adaptability to the operation. $300 0.18 0.33 0.47 Potassium. As with phosphorus, a soil test is the

$250 best guide to potassium needs (Table 9). Potas- 0.15 0.27 0.39 sium removal is much greater with silage than with grain production. Therefore additional potassium should be considered in cropping Percent of N of Percent 82% 46% 32% sequences including forage sorghum. Potassium deficiencies are most likely to be found in claypan soils with shallow rooting depths and on sandy soils.

Potassium should be applied preplant-broadcast, preplant-knifed, or banded at seeding. Broadcast applications should be thoroughly incorporated to get the potassium in the root zone. The most Nitrogen Fertilizer Nitrogen Table 5. Table Nitrogen of Amounts Various For Nitrogen of Fertilizers in Dollars per Pound Common Nitrogen of Price Anhydrous Ammonia (NH3) Ammonia Anhydrous Urea UAN (32-0-0) UAN common potassium source is muriate of pot- 44 | Fertilizer Requirements Fertilizer Requirements | 45 ash (potassium chloride); however, potassium by either suppressing the disease organism or sulfate, potassium nitrate, potassium-magnesium improving overall plant health and allowing the sulfate and mixed fertilizers are good potassium plant to withstand infection. Chloride responses sources. These sources differ little in potassium have been noted even in absence of disease, availability for crops. Selection should be based suggesting some soils may not be able to supply on cost, availability and adaptability to the farm needed amounts of chloride. Soil test calibra- operation. tion experiments have shown that when soil test chloride levels (0 to 24 inches) are less than 20 Lodging of grain sorghum at maturity can be to 30 lbs. per acre, responses to applied chloride a problem in many areas of Kansas and can are likely. Chloride is a very mobile element in result in considerable harvest loss. Research has soils, similar to nitrogen, and a 24-inch sample is shown that lodging occurs due to many fac- needed to adequately gauge soil chloride content. tors—weather stress, insect and disease damage, Table 10 illustrates the value of chloride applica- hybrid stalk strength, date and rate of planting tion on grain sorghum. On a Crete silt loam soil and nutrient imbalance. Adequate potassium in north-central Kansas application of chloride is essential for sturdy stalks, and research has on a deficient soil (12 lb. Cl/acre) resulted in a shown potassium fertilization can reduce yield increase of 11 bushels per acre over the lodging on medium to low-testing soils. Recent unfertilized check. research has shown adequate chloride may be as important as potassium in stalk strength. Potas- Liming. Lime recommendations are intended sium chloride at 40 to 50 lbs. per acre supplies to maintain productive soils. Sorghum is not adequate chloride. the most responsive crop to lime, but liming of acidic soils should not be ignored. Although High application rates of potassium fertilizer for yield increases may be small, liming is a sound insurance against lodging is not recommended. farming practice. In the Eastern Plains, lime is Fertilization with proper levels of all nutrients recommended for sorghum on soils with a pH of plus good crop-management practices in general 6.0 or less. In the Central Plains, lime is recom- is the best way to minimize lodging. Weather mended for sorghum on soils of pH 5.5 or less. conditions play a major role in lodging, and they If sorghum is grown in a cropping system that cannot be controlled. includes legumes, the pH should be maintained at the optimum pH for the legume. Chloride. For many grain crops, chloride has been reported to have an effect on plant diseases Other Elements. Research has demonstrated a 46 | Fertilizer Requirements Fertilizer Requirements | 47 need for some secondary and micronutrients in cable to zinc. Inorganic and organic (chelate) some situations (e.g. zinc and iron), but others sources of zinc are available for application, but are typically not limiting. Calcium and magne- the chelates are generally three to five times sium are relatively abundant in most soils in the more effective per lb. of metal. Small applica- Central and Eastern Plains. Liming of acidic soils tion rates are more effective if banded close to supplies sufficient calcium, and a deficiency of the seed. No economical source of iron for soil this element would not be expected. Research with boron, copper and manganese has not application is currently available for correction revealed any consistent responses, and these of iron deficiency in sorghum. Foliar sprays of elements should not be a problem for optimum iron and manure application are the most effec- sorghum yields. tive methods of correcting iron chlorosis.

Sulfur may be lacking on sandy soils low in Figure 3. Effects of Rotation and Nitrogen Rate on Grain organic matter (less than 1.5%). On irrigated Sorghum Yields, Belleville, Kan. (1982-2002). sandy soils sulfur would only be of concern when sulfur levels in the irrigation water are low. Much of the irrigation water in the Central Plains contains an appreciable amount of sulfur. Current sulfur soil tests, when used alone, are poor predictors of sulfur deficiency. Farmers with sandy soils low in organic matter and a low sulfate soil test should try sulfur to ascertain the likelihood of a sulfur response.

The need for zinc and iron can be predicted by soil tests. Zinc is most likely deficient on areas where the topsoil has been removed and under high-yield conditions. Iron deficiency is most likely to occur on soils where erosion or leveling has exposed a highly calcareous subsoil, which also is low in organic matter and has a high pH. Zinc usually is applied in conjunction with phosphorus and potassium, and time and method of application discussed in those sections are appli- 48 | Fertilizer Requirements Fertilizer Requirements | 49

Table 7. Nitrogen Credits for Legumes in Rotations (With Stand Destruction Tillage) Alfalfa Excellent Stand (> 5 plants/sq ft) -120 lb. N/A 7 31 18 13 25 15 10 20 13 lb. Good Stand (2-5 plants/sq ft) -80 lb. N/A Magnesium Fair Stand (1-2 plants/sq ft) -40 lb. N/A

8 Poor Stand (< 1 plant/sq ft) 0 lb. N/A 38 20 18 26 12 14 18 lb. 10 Sulfur Red Clover Excellent Stand -80 lb. N/A 7 5 3 32 25 25 20 18 15 lb. Good Stand -40 lb. N/A Calcium Fair Stand 0 lb. N/A O 2 Sweet Clover 35 15 30 25 170 135 120 125 100

lb. K lb. Excellent Stand -110 lb. N/A Potassium Good Stand -60 lb. N/A

5 Poor Stand 0 lb. N/A O 2 90 20 70 76 16 60 42 12 30 For No-Till production reduce N credit adjustment by 50%

lb. P lb. Source: "Using Legues in Rotation" Pub. No. L-778, Kansas State Phosphorus University Research and Extention, Manhattan, KS 66506 95 80 70 lb. 95 240 145 200 120 165 Nitrogen Nitrogen lb. Dry 9,520 8,510 7,980 6,780 6,750 5,080 18,030 14,760 11,830 Matter Part Total Total Total Plant Plant Grain Grain Grain Grain Stover Stover Stover 180 140 100 bu/a Yield Nutrient Content of Above ground parts of Grain Sorghum Grain parts of ground Above of Content 6. Nutrient Table 50 | Fertilizer Requirements Fertilizer Requirements | 51 and Extension, Manhattan, KS 66506 Source: Test "Soil Interpretations and Recommendations" Fertilizer Pub. No. MF-2586, Kansas State If Exch K is less than 130 ppm, minimum the then K Recommendation = 15 lb. K2O/A If Exch K is greater than 130 ppm, only then a NKP or is suggested NPKS fertilizer started [ 58 + (0.17 x YieldK Rec= + (Exch K x -0.616) + (Yield Goal) x Exch K x -0.0013)] Goal Grain Sorghum Sufficiency Crop Removal 130+ 120-130 80-120 40-80 0-40 TestSoil K Table 9. PotassiumRecommendations Sufficiency for Grain Sorghum (ppm) 0 80 15 30 50 70 200 40 10 15 20 45 75 0 0 64 15 30 45 65 160 80 21 15 20 50 80 0 Yield bu/A Goal, Lb. P /A 5 120 O 31 15 25 55 85 0 2 0 2 48 15 25 45 60 O 120 5 /A Lb. P Lb. Yield Goal, bu/A Yield 160 42 15 25 60 90 0 0 32 15 25 40 55 80 200 52 15 25 60 95 0

0 Table 10. Grain Sorghum Response to Chloride 16 15 20 35 50 40 (3-year average), Bellvelle, Kan. Chloride Yield lb./acre bu/acre 0 120 20 131 40 133 LSD (0.05) 5 Grain Sorghum Sufficiency Sorghum Grain P x -0.008)] Goal x Bray P x -2.5) + (Yield Goal) + (Bray P Rec= [ 50 + (0.16 x Yield started fertilizer NPKS suggested a NP or then only 20 ppm, than greater P is Bray If P2O5/A = 15 lb. P Recommendation then the minimum 20 ppm, than less P is Bray If Crop Removal Crop 20+ 15-20 10-15 5-10 (ppm) 0-5 Phosphorus Sufficiency Recommendations for Grain Sorghum Grain for Sufficiency Recommendations 8. Phosphorus Table P Soil Test KS 66506 Manhattan, Extension, and State Kansas MF-2586, No. Pub. Fertilizer Recommendations" and Interpretations "Soil Test Source: Soil test chloride= 12 lb./acre (0 to 24 inches) 52 | Weed Control Weed Control | 53

creating problems for the subsequent sorghum Weed Control crop. Do not plant grain sorghum when a Weed control in grain sorghum remains a chal- severe shattercane or Johnson grass infestation is lenge and is best achieved with an integrated expected. approach using crop rotation, good crop production practices, herbicides and/or tillage. This Common annual broadleaf weeds in sorghum integrated approach enhances the ability of include kochia, Russian thistle, Palmer amaranth, sorghum to compete with weeds. Before plant- waterhemp, redroot and tumble pigweed, venice ing grain sorghum, fields should be evaluated for mallow, velvetleaf, cocklebur, morning glory, annual and perennial weeds. The current year’s devils claw and sunflower. Successful control of weed-management program should be based on annual weeds requires planting the crop into a field notes from previous years that show weed weed-free environment and other management species present, their relative abundance, and practices designed to promote crop emergence locations of perennial-weed infestations. before weed emergence. Timely post-emergence applications to small broadleaf weeds following a Common grassy weeds include crabgrass, pre-emergence herbicide provide the most effec- foxtails, shattercane, longspine sandbur, prairie tive season long weed control. Sorghum should cupgrass, fall panicum and witchgrass. In grain remain nearly weed free the first four to five sorghum, the use of pre-emergence grass herbi- weeks after planting to prevent yield loss from cides is essential to get adequate control of most weed competition. of these grass species. Planting crops in rotations that allow the use of pre or post grass herbi- Perennial weeds such as field bindweed, com- cides can prevent weed seed production during mon milkweed, hemp dogbane, bur ragweed that growing season and can reduce the weed (woolly leaf bursage), tumble windmill grass and seed-bank. Because grass seed viability in soil johnsongrass also may infest sorghum fields. is relatively short for many of these species, main- Perennial weeds can be suppressed, but often are taining grass weed control for four to five years difficult to kill. Cultivation between the rows, can greatly reduce the grass weed pressure in directed herbicide applications with drop nozzles, future growing seasons. Thus, it is also important and certain broadcast herbicides are helpful in to prevent these grass weeds from producing seed suppressing perennial weeds in the sorghum during a fallow period. Grass weeds that produce crop. Crop rotation with alternate herbicides and seed during a fallow period (i.e. in wheat stubble additional control measures during fallow peri- following wheat harvest) replenish the seed bank, ods will help control perennials. Fall herbicide 54 | Weed Control Weed Control | 55 applications following sorghum harvest and prior cially effective in late seeded crops. Although to a killing freeze can provide control of some delayed sorghum planting can help mange weeds perennial species like bindweed and bur ragweed. in certain situations, it increases the risk of crop failure due to a fall freeze prior to physiological Crop rotation is a key component of integrated maturity. Late planted sorghum and shorter weed management because it can reduce weed season hybrids often have inherently lower yield pressure by varying the timing and types of potential. tillage and herbicides used in the system. This is the most effective control for shattercane and Weed Control Strategies Prior to Planting. johnsongrass in sorghum. Fallow periods and When sorghum follows wheat from the previ- rotation with glyphosate-tolerant summer crops ous year, weeds must be controlled in the wheat such as soybeans, corn, and cotton or winter stubble to prevent weed seed production. Using crops such as wheat and canola, will greatly glyphosate and 2,4-D or dicamba can provide reduce weed numbers with timely weed control excellent broad-spectrum weed control. An to prevent weed seed production during the atrazine application in late October or into rotational period. November will help control volunteer wheat and other winter annual weeds, and should keep the Delayed sorghum planting provides opportuni- field relatively weed-free for a no-till sorghum ties for effective weed control. In tilled seedbeds, planting the following spring. The addition of field cultivation prior to planting will control glyphosate is important if winter annual grasses emerged weeds and stimulate the onset of an are present. The addition of 2,4-D will help additional flush of weed germination, reduc- provide adequate winter annual broadleaf weed ing weed-seed stocks in the soil. The last tillage control. before planting should be very shallow to avoid bringing new weed seed to the soil surface. In Repeated herbicide (glyphosate + growth regula- no-till seedbeds, herbicides are used to control tors) applications or tillage before sorghum plant- emerged weed seedlings. Once several flushes of ing can effectively control weeds. Tilled ground weed seedlings have been killed without further is not likely to provide adequate protection from soil erosion by wind and water. Timely herbicide soil disturbance, weed pressure is often reduced applications can substitute for tillage in no-till because few weed seeds remain in the germina- systems to increase water conservation and tion zone near the soil surface. No-till especially reduce soil erosion. reduces the large seeded broadleaf weed populations. Using “stale seedbed” techniques are espe- On fine-textured soils in central and eastern 56 | Weed Control Weed Control | 57

Kansas, no-till planting of sorghum into stand- be very effective on established perennials such as ing wheat stubble may be hindered by wet soils. field bindweed and hemp dogbane. Soil-residual An alternative to no-till planting is to chisel the grass herbicides can be added with these foliar- stubble after wheat harvest, leaving a rough but applied treatments for extended weed control. A protected and porous surface. Apply atrazine and new herbicide, Sharpen, is a PPO inhibitor and crop-oil concentrate to volunteer wheat and other can provide excellent control of broadleaf weeds, winter weeds in the fall. A single pass with a field including mares tail. Sharpen should be applied cultivator in spring is usually sufficient to assure with crop oil or methylated seed oil and can be a weed-free seedbed for sorghum planting. tank-mixed with glyphosate. Use high surfactant oils when mixing with glyphosate. Sorghum planted into soybean or row-crop stubble normally requires no seedbed preparation Herbicides Applied at Planting. It is critical that other than a burndown herbicide application. fields be weed-free at planting and remain nearly Where weed pressure is light and mainly broad- weed-free the first several weeks of the sorghum leaf weeds, a March or early-April application of life cycle to optimize yield potential. Soil-applied atrazine with crop-oil concentrate and 2,4-D can pre-emergence herbicides for grass and pigweed control winter annual weeds such as mustards control in sorghum include: Dual II Magnum, and mares tail, and provide control of most metolachlor, Cinch, Outlook and Intrro (there germinating weeds up to planting. Early spring are several other generic herbicides). These herbi- applied atrazine is a best management practice cides may be shallowly incorporated or surface (BMP) to minimize off-site atrazine movement applied, and require the use of sorghum seed as there is little potential for loss in surface-water treated with a safener. These soil-applied herbi- runoff compared to later planting-time applica- cides do not control shattercane or large-seeded tions. Leaving these weeds uncontrolled until broadleaf weeds such as cocklebur, velvetleaf, the final burndown after or just prior to grain venice mallow, morning glory, devils claw or sun- sorghum planting can result in inadequate weed flower. These herbicides are most effective when control. applied with atrazine, and often are marketed in a prepack mixture. Examples include: Bicep II If annual grasses and tough broadleaf weeds like Magnum, Bicep Lite II Magnum, Bullet, Lariat, velvetleaf emerge as planting time nears, glypho- Guardsman Max and G-Max Lite. Additional sate and one pint of 2,4-D ester should be applied generic herbicides exist containing these same at least one week before planting. In addition to active ingredients. In addition, Degree Xtra, killing emerged annual weeds, this treatment can which contains encapsulated acetochlor (grass 58 | Weed Control Weed Control | 59 and small seeded broadleaf weeds) and atrazine, is registered for use in sorghum. These prepack The rate of atrazine applied to the soil surface mixtures that include atrazine provide broad at planting should not exceed 1 lb. per acre, spectrum grass and broadleaf weed control; especially where soils are vulnerable to surface- however do not adequately control most large water runoff during May and June. Alternatives seeded broadleaf weeds, shattercane, or some for using higher rates of atrazine at planting triazine-resistant broadleaf weeds. Two examples time include surface application before April 15, of problematic triazine-resistant weeds com- preplant incorporation, or application in bands monly found in the Central and Eastern Plains over the sorghum row. (Photos 1-3)* are Palmer amaranth and kochia. Herbicides Applied Post-emergence. Post- Several newer herbicides may help control large emergence herbicides should be applied to small seeded broadleaf and triazine-resistant weeds. weeds for optimum weed control. Bromoxynil Sharpen contains a PPO inhibiting herbicide, (Buctril, Moxy and others), carfentrazone (Aim and others), bentazon (in Laddok) and atrazine saflufenacil, that provides burndown broadleaf all kill weeds through foliar contact and do not weed control and very short residual broadleaf move through the plant; therefore, weeds may weed control including control of large seeded recover even after having lost their leaves. This broadleaf weeds. The 1 to 2 ounce per acre rate is especially true on larger weeds. Systemic of Sharpen however, will provide perhaps one herbicides such as 2,4-D, Banvel, Starane, Peak, to two weeks residual broadleaf weed control. Permit, Paramount and Yukon are translocated Sharpen will need to be applied with one of from the leaf surface throughout the plant and the chloracetamides or one of the prepackage are more effective on larger annual broadleaf mixtures of a chloracetamide and atrazine listed weeds; however larger weeds become increas- above. Lumax or Lexar contain the HPPD inhib- ingly difficult to control. Some of these systemic iting herbicide mesotrione (Callisto) plus Dual II herbicides may help control perennial weeds. Paramount is especially effective for control of Magnum and atrazine. Lumax is the low atrazine field bindweed, and Permit and Yukon are some load version of these prepack herbicides. Lumax of the more effective herbicides for control of or Lexar can provide excellent control of grasses yellow nutsedge. and broadleaf weeds including velvetleaf and triazine-resistant Palmer amaranth and kochia. The only foliar-applied herbicides that can con- Lumax and Lexar should not be used on sandy trol annual grasses in sorghum are atrazine with soils because of excessive risk of crop injury and sorghum stand loss. *Photos found in Appendix B page 111 60 | Weed Control Weed Control | 61 crop-oil concentrate, or 5.3 to 8 ounces of Para- weed control are Aim (carfentrazone) and Prior- mount with methylated seed oil. For adequate ity (Aim + Permit). Aim is a PPO inhibitor, and control, these herbicides must be applied to very can help control triazine and ALS resistant weeds small (one to two inch) grass seedlings. Atrazine if applied when weeds are small. Aim is especially at more than 1 lb. per acre is not considered a effective for control of velvetleaf. If Ally is used, best management practice, especially where there it is essential to tank-mix with 0.25 lb. 2,4-D is high potential for atrazine loss in surface-water amine as the 2,4-D amine reduces the grain runoff. Current work is underway to develop sorghum response to Ally. Dicamba (Banvel or sorghum hybrids that will tolerate grass herbi- Clarity) and 2,4-D are among the least expensive cides that normally kill grain sorghum. This new herbicides for broadleaf weed control in sor- technology will allow post-emergence annual ghum. These herbicides act as growth regulators, grass control in grain sorghum, but will be an often causing temporary leaning and brittleness option only on the non-GMO herbicide resistant in sorghum plants, especially if applied when sorghum hybrids. sorghum is less than 2 inches in height. Such plants are more vulnerable to wind and cultivator Fewer herbicides are available for broadleaf-weed damage. Application to sorghum more than 8 control in sorghum than in corn or soybean. inches tall should be made with drop nozzles to Products such as bromoxynil plus atrazine, Lad- reduce potential for sorghum injury. Application dok S-12, Marksman, and Shotgun all contain of 2,4-D or dicamba after sorghum exceeds 15 about 0.5 lb. atrazine along with other herbicides. inches tall, may result in sterility and severe yield They should be applied when sorghum is in the reductions. There is limited evidence that sug- three- to six-leaf stage and weed sizes conform to gests sorghum hybrids may vary in their response label guidelines. to these growth regulator herbicides, but all hybrids are susceptible to damage, especially if Peak, Permit and Ally are sulfonylurea herbi- the herbicides are misapplied. (See photos 4-6)* cides used in sorghum that work by inhibiting the function of the acetolactate synthase (ALS) Cultivation of Sorghum Rows. Cultivation enzyme. These herbicides are often tank-mixed remains an integrated option for control of with dicamba, 2,4-D and/or atrazine to control emerged weeds, however it has become very a broader spectrum of weeds and to help control unpopular because of fuel costs, time and labor ALS-resistant weed species that may be immune involved. Cultivation can be an emergency to ALS inhibiting herbicides. Additional her- backup where herbicides have performed poorly bicides available for post-emergence broadleaf *Photos found in Appendix B page 112 62 | Weed Control Weed Control | 63 and where perennial weeds have not been con- 30/ft2 in irrigated sorghum reduced grain yield trolled. Electronic guidance systems can increase nearly 50%. In Nebraska, weed interference with cultivating speed and efficiency by reducing velvetleaf was dependent on the sorghum hybrid operator fatigue and cultivator blight. Heavy, that was selected. Perennial weed management high-residue cultivators can be effective even in may require an integration of cultivation, crop no-till planted sorghum. rotation, fall herbicide applications prior to frost, delayed burndown application, broadcast Grain Sorghum Weed Control in the herbicide application, and directed herbicide Eastern Great Plains application to control or suppress these weeds. A combination of chemical and mechanical The Eastern Great Plains has a diversity of weed control is generally very effective for grain climatic conditions, soil types, cropping systems sorghum production. and weed species which affect weed management decisions in the region. Weed control in grain Cultivation effectively reduces weed interference sorghum may utilize an integration of mechani- from between the crop rows. Although cultiva- cal, chemical and cultural methods to help tion is usually not an option in narrow-row sorghum compete with weeds. Conditions that sorghum production, canopy development in are favorable for quick germination allows grain narrow rows is quicker. Narrow-row spacings sorghum a competitive advantage over weeds. (less than 30 inches) can reduce the amount of Unfavorable conditions including delayed emer- light available to seedling weeds. In Kansas, gence, cool and wet soils, deep planting depth, narrow row sorghum reduced weed growth up seedling diseases, and seed quality may result in to 45% and increased yield over 30 bushels per increased seedling stress due to weed interference acre when compared to 30-inch rows. Effective and/or crop injury due to herbicide application. chemical weed control depends on matching the Weed interference in grain sorghum causes correct herbicide timing and rate with the weeds reduced yields, harvest interference and losses, present in the field. Table 11 provides a guide for grain contamination with debris, and increased weed response to herbicides at suggested applica- weed seed in the soil seed bank. Weed inter- tion rates in the Eastern Great Plains. Several ference greater than two weeks after sorghum tank-mixture or pre-mix combinations with emergence generally reduces yields depending herbicides such as 2,4-D, dicamba or atrazine on the environmental conditions, weed species are available. Only combinations reported from and density. Research has shown over a 3% multiple sources in the Eastern Great Plains reduction in sorghum yield for every week of states were reported. It is reasonable to combine grass competition, while pigweed densities up to 64 | Weed Control Weed Control | 65 the weed control ratings for individual products herbicide rates are based on the amount of for pre-mix and tank-mixture components. Indi- residue cover present, whether the soil is highly vidual state weed control guides in the Eastern erodible, soil texture (coarse, medium, or fine), Great Plains are available annually with label and preplant incorporated or preplant surface appli- weed management updates. cation, organic matter and specific weed management issues such as grass weed species and yellow A clean field at planting is desirable using tillage nutsedge. In addition, herbicide rates such as or a burndown herbicide such as gramoxone, atrazine applied on highly erodible soils have glyphosate or glyphosate plus 2,4-D or dicamba been limited to reduce the potential for surface can be utilized for no-till planting. Pre-emer- water runoff loss. Best management practices gence herbicides are commonly used to control have been developed to reduce herbicide losses in weeds in grain sorghum due to the cost-effective- surface water runoff in the Eastern Great Plains. ness and lack of available post-emergence grass Herbicide losses generally occur following an herbicides. Pre-emergence herbicides must be atrazine application especially when soils remain applied prior to weed germination. Irrigation wet for extended periods of time. Fall applica- or rainfall following application is important for tions in areas of the Eastern Great Plains help activation of these herbicides to ensure adequate avoid risks associated with runoff losses. This is herbicide uptake by the weed. Excessive rainfall beneficial for controlling winter annual weeds may result in temporary crop injury, and under and reducing the need for a burndown herbicide normal growing conditions these symptoms are application and preplant tillage. However, some usually temporary. Fields with high populations areas in the Eastern Great Plains do not allow of grass weeds may need to be avoided since fall applications of atrazine. Producers should limited post-emergence grass control options are refer to specific state and region recommenda- available. Atrazine is commonly applied in com- tions for such applications. In addition, specific bination with chloroacetamide herbicides (Dual restrictions on use are also dependent on local II Magnum, Intrro, or Outlook) as a pre-mix or conditions such as specific watershed regulations tank-mixture. Since grain sorghum lacks toler- or requirements. ance to several grass and broadleaf herbicides, application recommendations must be carefully Tillage prior to planting can effectively control followed. When using chloroacetamide herbi- winter annual and early spring annual weeds; cides, seed must be treated with a safener such as however, tillage causes the soil to be susceptible Concept or Screen, to prevent injury caused by to wind and water erosion. Tillage allows a these herbicides. Recommended pre-emergence producer to incorporate atrazine and companion 66 | Weed Control Weed Control | 67 herbicides such as Dual II Magnum, Outlook man, Shotgun, Banvel-k + atrazine or Buctril + and Intrro which can reduce atrazine runoff up atrazine to provide additional post-emergence to 60%. Reduced rates and banding herbicides grass control or suppression to small seedling can also be utilized to reduce the amount of grasses. Since there are no selective post-emer- herbicides applied per acre. Reduced rates of gence herbicides available for control of Johnson atrazine are available in pre-mixes such as Bicep grass or shattercane, fields with infestations of Lite II Magnum, Cinch ATZ Lite or G-Max Lite these weeds should be avoided. Current research to minimize runoff loss in sensitive watersheds. is evaluating herbicide resistant grain sorghum Cultivation or post-emergence herbicides can be for post-emergence control of Johnson grass, utilized in conjunction with reduced rates and shattercane and other grasses that are difficult to banding to provide good control of weeds. Rates manage in grain sorghum. Post-directed, hooded of atrazine may increase when incorporated prior and rope wick applications are available and can to planting, applied as an in-row band or applied be effective for control of escaped weeds in taller to soils that are not highly erodible. A post-plant grain sorghum. Post-directed or hooded applica- incorporation of Prowl or Treflan with a sweep tions may result in severe crop injury. A hood is type or rolling cultivator can be used to extend required to avoid drift and prevent contact with residual grass control until sorghum is 12 inches sorghum plants when applying glyphosate. A tall. post-directed application of Lorox or Gramox- one before the crop is 15 inches tall must avoid There are fewer post-emergence herbicides avail- contact with crop leaves or significant crop injury able for control of weeds in grain sorghum than may result. Harvest aids such as Aim, Diquat in corn or soybean. Post-emergence herbicide and glyphosate are available to reduce the impact applications may be restricted based on the stage of weeds on harvest efficiency. Grazing and for- of crop development (refer to chapter 1, Growth age restrictions prevent illegal pesticide residues Stages) specified on the herbicide label in order when herbicides are applied to grain sorghum. A to minimize crop injury. Several post-emergence period of time should occur between herbicide herbicides are available for control of broadleaf application and grazing or harvest for silage to weeds; however few are available for control of avoid illegal pesticide residues. Always consult grasses. The addition of dicamba or atrazine to the herbicide label for specific limitations. several post-emergence herbicides is common to broaden the spectrum of weeds controlled and Herbicides used in the crop rotation such as increase control of certain broadleaf weeds. Atra- Flexstar and Pursuit in soybean, or Exceed, Hor- zine is commonly included in Laddok, Marks- net, Lightning, Resolve Q and Steadfast ATZ in

68 | Weed Control Weed Control | 69

Waterhemp species Waterhemp 1

corn, need careful consideration since carryover E E G E-G E-G G E-G E G G Venice mallow Venice

from a previous crop may cause injury and stand F- F P F F P F G P G reductions. Since grain sorghum is more drought Velvetleaf

tolerant, it may be planted when conditions were G-F G-F P G-F G-F P G-F E p G Sunflower, Common Sunflower,

not favorable for another crop. Herbicides that G-F G-F P G-F G-F P G-F G P G Smartweed, Annual Smartweed, were applied for that crop need to be taken into E G P G G P G E P G

consideration prior to planting grain sorghum. thistle Russian E-G E-G P G G P G G P G Sida, Prickly Sida,

Herbicide resistant weeds such as kochia, water- G E P E-G E-G P E-G E-G P G Ragweed, Giant Ragweed,

hemp and pig weeds in grain sorghum have been G G P G G P G G P G reported in the Eastern Great Plains states. If Common Ragweed, E E-G P G G P E-G G P G

you suspect a herbicide resistant weed, treat with Punturevine

a herbicide with a different mode of action and G G F G G P E-G G P G

Smooth

1 contact your local extension agent to confirm the & Redroot Pigweed,

E E G E E G E E G G

species presence of resistance in order to help manage 2 Morning glory glory Morning

these weeds. E-G E-G P E-G E-G P E-G E-G P G

Common Lambsquarters, Lambsquarters, E E G-F E E G-F E E G-F G

Broadleaves

Kochia

E-G E-G P E-G E-G P E-G E-G P G Jumsonweed

E-G E-G P E-G G P F G P P Devil's-claw

G-F G P F F P F G P P Cocklebur, Common Cocklebur,

E-G E-G P E-G E-G P E-G E-G P G

Eastern Black nightshad, nightshad, Black E E G E E G E E E-G G

3 Crop tolerance Crop G G G G G G G G G G 4 4 4 4 4 (alachlor + atrazine) (alachlor 4 4 4 not enough information to rank to information enough not Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None -= Herbicide preemergence incorporated or Preplant Atrazine ATZ II Magnum/Cinch Bicep Dual II Magnum/Cinch/Parallel Expert Max Guardsman Intrro/Micro-Tech/Lasso Lariat/Bullet Lumax/Lexar Outlook Sharpen

70 | Weed Control Weed Control | 71

Waterhemp species Waterhemp

G G-F E G P F E-G G G-F E G-F

Venice mallow Venice

P G P mallow Venice

G G G F E-G E-G E E

tleaf Velve

P E P Velvetleaf

E E E-G G E-G G E E Sunflower, Common Sunflower,

P G P Sunflower, Common Sunflower,

F-P E-G E-G E-G E-G E-G E E Smartweed, Annual Smartweed,

P E P

Smartweed, Annual Smartweed, Russian thistle Russian E-G F E E E E E E

P F P

Russian thistle Russian Sida, Prickly Sida,

G-F G F-P E-G P G E-G F

P G P

Ragweed, Giant Ragweed, Sida, Prickly Sida,

P G P F G E G G P E-G E

Ragweed, Giant Ragweed, Ragweed, Common Ragweed,

F - G E-G G E G G P E P

Punturevine Ragweed ,Common Ragweed

P F P F E-G E-G E-G E-G E-G E E

Smooth

Punturevine Pigweed, Redroot & & Redroot Pigweed,

F E-G G-F G F G G G G E-G G

species

Rigweed, Redroot & Smooth & Redroot Rigweed, Morning glory glory Morning 1

E-G E-G E E-G P G-F E-G E-G - F P

Common

Morning glory species glory Morning

Lambsquarters, Lambsquarters, 2 G-F E E-G E F E-G E-G G

F-G E G

Broadleaves Common Lambsquarters, Kochia

1 E-G E E G F E-G E E

- G G-F

Kochia

1 Jumsonweed G-F E-G E-G E-G F G E G

P G P

Jumsonweed Devil's-claw E-G F E-G G E E-G E E

P F P Devil's-claw

F E G P G-F G-F G G Cocklebur, Common Cocklebur,

P E-G P

Cocklebur, Common Cocklebur,

Eastern

F-G E E-G E E E-G E E Black nightshad, nightshad, Black

P E P Black nightshade, Eastern nightshade, Black

E-G F E E-G P E E E-G Crop tolerance Crop

G-F G-F G Crop tolerance Crop G F G F E G G E-G 3,5 O/Pendimax/ 2 4 wl + atrazine/Pendimax + wl + atrazine/Pendimax not enough information to rank to information enough not uctril/Moxy/Brocleam/ Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None information enough -= not rank to Herbicide Postemergence Aim Ally + 2,4-D + oil Atrazine Blue Banvel/Clarity/Sterling Basagran B Bromox Buctrul + atrazine Laddok S-12 Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None -= Herbicide incorporated Postplant H Prowl/Prowl Pro atrazine Treflan Pendant

72 | Weed Control Weed Control | 73

Waterhemp species Waterhemp Waterhemp species Waterhemp

E P F-P F P E F-P E-G G G - -

Venice mallow Venice Venice mallow Venice - - -

E-G P E G P E-G E-G G G-F Velvetleaf

G F E Velvetleaf

E-G P E-G E-G F-P G G E-G G Sunflower, Common Sunflower,

E - - Sunflower, Common Sunflower,

E F-P E E F E G E-G G Smartweed, Annual Smartweed,

G P G Smartweed, Annual Smartweed,

E F-P G G-F F E F E-G F-P Russian thistle Russian

- - - Russian thistle Russian

G F-P G P P - F G-F E-G Sida, Prickly Sida,

E P E Sida, Prickly Sida,

E P G-F G-F F-P E - G G Ragweed, Giant Ragweed,

G - - Ragweed, GIant Ragweed,

G - G G F G - E G

Ragweed, Common Ragweed,

Ragweed, Common Ragweed, E G G

E F-P E-G E-G F E E-G E E-G

Punturevine

Punturevine - - -

- - E G P G E-G G G

Rigweed, Redroot & Smooth & Redroot Rigweed,

Rigweed, Redroot & Smooth & Redroot Rigweed, 1

1 E E E-G

E-G F-P E-G G P E F-P G E-G

Morning glory species glory Morning

G P G Morning glory species glory Morning

E E-G G-F F-P P E E-G G E Lambsquarters, Common Lambsquarters,

G E E Lambsquarters, Common Lambsquarters,

E F-P G-F P P E P E-G G

Kochia

- - - Kochia

E-G F-P G-F G-F F G E G F Jumsonweed

E F - Jumsonweed

E P G F G E F G G-F Devil's-claw

- P - Devil's-claw

- - E G F E G-F G E

Cocklebur, Common Cocklebur, Cocklebur, Common Cocklebur, E F-P G

E P E E G E G E E

Black nightshade, Eastern nightshade, Black Black nightshade, Eastern nightshade, Black E - -

E F-P F-P P P E-G G-F F F

Crop tolerance Crop Crop tolerance Crop F G G G-F G E-G E-G G F-P G-F F P 3,5 6 wn oundup/Durango DMA/ oundup/Durango Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None information enough -= not rank to Herbicide hooded or Post-directed DMA/ Roundup/Durango Touchdown INteon Gramoxone Lorox/Linex Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None information enough -= not rank to Herbicide Postemergence + Marksman/Banvel-K atrazine Paramount Peak Permit/Sandea R Touchdo Shotgun Ultra Starane Yukon 2,4-D

74 | Weed Control Weed Control | 75

Yellow nutsedge Yellow Yellow nutsedge Yellow

G F G G G G F G G - P F P

(rhizome)

Johnsongrass Johnsongrass Johnsongrass Johnsongrass

P P P P P P P P P P-

P P P

(seedling)

Johnsongrass Johnsongrass

ohnsongrass ohnsongrass Perennials J

Perennials F P F F F F F F F F-

F F F

Bindweed, Field Bindweed, Bindweed, Field Bindweed,

P P P P F P P P P - - - -

Woolly cupgrass Woolly Woolly cupgrass Woolly

F P F F F F F F F - - - -

Witchgrass Witchgrass

E-G F E-G G E-G E-G G E G - - - E-G

Shattercane Shattercane

P P P P P P P P P - F F G

Sandbur species Sandbur Sandbur species Sandbur

E E E F F-P F F F F F F F -

Red rice Red Red rice Red

- - - E-G G-F E-G E-G E-G E-G E-G E-G E-G -

Goosegrass Goosegrass

E E G E P E E E E E E E -

Grasses Grasses

Foxtail species Foxtail Foxtail species Foxtail

E-G E-G E-G E G-F E E-G E E E-G E E-G -

Fall panicum Fall Fall panicum Fall

G G G E-G P E-G E-G E-G E-G E-G E E-G -

Crabgrass Crabgrass

E-G E-G E-G E-G F E E E E E E E -

Broadleaf signalgrass Broadleaf Broadleaf signalgrass Broadleaf

- F - F F-P F-G F E-G G-F G-F G-F G-F -

Barnyardgrass Barnyardgrass 3 E-G E-G E-G E-G G-F E-G E-G E-G E-G E-G E E-G - 4 4 4 4 alachlor + atrazine) alachlor O/Pendimax/Pendant 2 4 ( 4 4 4 Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None rank to information enough -= not Herbicide preemergence incorporated or Preplant Atrazine ATZ II Magnum/Cinch Bicep Dual II Magnum/Cinch/Parallel Expert Max Guardsman Intrro/Micro-Tech/Lasso Lariat/Bullet Lumax/Lexar Outlook Sharpen Post-plant incorporated Post-plant H Prowl/Prowl + atrazine/Pendimaz/Pendant Prowl Treflan Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None rank to information enough -= not Herbicide

76 | Weed Control Weed Control | 77

Yellow nutsedge Yellow Yellow nutsedge Yellow

P P P P G F F G

P P P E P P P E P

(rhizome)

(rhizome) hnsongrass hnsongrass Jo P P P P N P P P Johnsongrass

P - P P E-G P P P P

(seedling)

hnsongrass hnsongrass Jo Perennials Johnsongrass

P P P P N P P P Perennials

P - P P E-G P P P P

Bindweed, Field Bindweed, Bindweed, Field Bindweed,

F-P F-P P F-P P P P P

P E-G F-P - P P G-F F-P G-F

Woolly cupgrass Woolly Woolly cupgrass Woolly

P P P P N P P -

P F P P - P P P P

Witchgrass Witchgrass

P P P - N - P P

P F - - - P - - -

Shattercane Shattercane

P P P P N P P P

P P P P E-G P P P P

Sandbur species Sandbur Sandbur species Sandbur

P P F-P P N P P F-P

F-P F-P P P - F-P P P P

Red rice Red Red rice Red

P P E P N P P E

E - P P - E P P P

Goosegrass Goosegrass P P P P N P P P

P F P P - P P P P Grasses

Grasses

Foxtail species Foxtail

Foxtail species Foxtail 2

P P F P N P P F 2

F-P G-F P P - F P P P

Fall panicum Fall Fall panicum Fall

P P P P N P P P

P P P P - P P P P

Crabgrass Crabgrass

P P F-P P N P P F

F-P F-P P P - F P P P

Broadleaf signalgrass Broadleaf Broadleaf signalgrass Broadleaf

Pp P F-P N N N F-P F

F-P - N P - F N N N

Barnyardgrass Barnyardgrass P P F P N P P G F F P P - G P P P 6 4 4 3,5 4 3,5 4 4 Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None rank to information enough -= not Herbicide Post-emergence Aim Ally + 2,4-D + oil Atrazine Blue Banvel/Clarity/Sterling Basagran Buctril/Moxy/Broclean/Bromox Buctril + atrazine Laddok S-12 Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None rank to information enough -= not Herbicide Postemergence + atrazine Marksman/Bancel-K Paramount Peak Permit/Sandea DMA/Touchdown Roundup/Durango Shotgun Ultra Starane Yukon 2,4-D 78 | Weed Control Insect Management | 79

Insect Management Yellow nutsedge Yellow

F P - Sorghum insect pests vary widely from year to Johnson grass grass Johnson

G P P year, during different times within a growing

Johnson grass grass Johnson season and across the region. Greenbugs have E G F

Perennials Bindweed, Field Bindweed, historically caused problems throughout the

- - - region, and are still present every year, but have Woolly cupgrass Woolly not reached levels of economic consequence for - - -

several years. Sorghum may still be vulnerable Witchgrass

- - - to greenbug damage at any growth stage, but for Shattercane various reasons has not been affected. Chinch

E F-P - bugs are a continuous concern throughout the Sandbur species Sandbur

- - - region, with localized infestations sufficient Red rice Red enough to cause seedling stand reductions,

- E P replanting or insecticide applications. Sorghum Goosegrass

G G F midge populations cause local concern every year Grasses

Foxtail species Foxtail in the southeast occasionally in south-central 2

E G G fields. Sugarcane rootstock weevils are another Fall panicum Fall

G G G perennial pest in central Kansas and north Crabgrass central Oklahoma. Foliage-feeding insects such

E E-G G as fall army worms and cattail caterpillars cause Broadleaf signalgrass Broadleaf

F E F concern annually, but do little economic damage. Barnyardgrass Corn earworms (sorghum headworm), fall army E E F worms and army worms attack sorghum heads some place throughout the region every year, often requiring insecticide applications. These worms can reduce yield very quickly because they are feeding directly on the marketable product. 4

oundup/Durango DMA/ oundup/Durango The following table describes the insects of most Weed control Weed (>90%) E=Excellent G= Good (80-90%) (65-80%) F=Fair (<65%) P=Poor N=None information enough -= not rank to Herbicide hooded or Post-directed R Touchdown Gramoxone Lorox/Linex frequent concern in the Central and Eastern Plains: 80 | Insect Management Insect Management | 81 Probable insect Probable Flea beetles Thrips Cutworms Probable insect Probable wireworms, False seed beetles, corn wireworms ants, kafir Wireworms grubs White Distribution Region- wide Region- wide Region- wide - Region- wide Region- wide Region- wide Distribution Poor emergence of plants or seeds fail to germinate. seeds germinate. to or fail plants of emergence Poor destroyed or Seeds injured mechanically in the season. lodging Occa early - or stunted Plants stems portion of Underground die. plants sionally, Hard-shelled feeding. and tunneling of signs show larvae be present. may yellowish severely or lodged. Roots destroyed or stunted Plants grubs whitish present. C-shaped pruned. Description Description a as shows Pattern away. chewed tissue leaf of epidermis Upper destrucmechanical - stripes. Definite whitish series or streaks of beetles, shiny hard-shelled, be can observed. tissue of Tiny, tion when disturbed. rapidly jump long, 1/16 inch on present streaks Small, fine white flea to Similar beetle injury, the on insects present Small splinter-like tissue. leaf surface of varies color long; 1/16 inch Less that in the usually whorls. plants, not. some winged, some dark; to transparent from sur the soil or below above just off cut partially totally or Plants under generally be present, may worms blackish to Brownish face. plants. injured the of soil surface in the vicinity Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table crop year/ of Time stage growth 4. Seedlings to plants 6-inch 5. Seedlings to plants 6-inch 6. Seedlings to plants 6-inch 1. Planting time; seed- 1. Planting insects attacking season 2. Early season 3. Early Insects of Frequent Concern in Sorghum Frequent of 12. Insects Table growth crop year/ of Time stage 82 | Insect Management Insect Management | 83 Wrieworms. Wrieworms. - root cane sugar weevil, stock, bugs, chinch grubs. white Greenbugs* Probable insect Probable Probable insect Probable Corn leaf aphids* bugs* Chinch Region-wide Region-wide Distribution Distribution Region-wide Generally more in common the Eastern usually Plains, in sorghum adjacent fields wheat to Plants stunted and/or wilting. Brace roots deformed. Stems, Stems, deformed. roots Brace wilting. and/or stunted Plants tunneling. or feeding of signs with ground above and both below destroyed. Roots or pruned Small seedlings show signs of reddening, sometimes plants plants sometimes reddening, of signs Small seedlings show the plant. of portions above-ground on present Insects dying. if insects sometimes soft-bodied green light insects, Or, Tiny, foliage on present skins cast whitish numerous disappeared, have plants. affected soil around and Description Description Medium to dark green sucking insects present, especially in insects present, sucking green dark to Medium on present tail-pipes or cornicle Prominent plants. of whorls in color. darkish are Tail-pipes body. of rear side near upper Generally in color. also is darkish tail-pipes base of around Area these with insects, injury associated they visible even though no . numerous be quite may Damage generally appearing at the margin of the field and and the field of the margin at appearing generally Damage high 6 inches 0 to signs show Small plants inward, progressing discoloration reddish much Occasionally dying, or stunting of bugs full-grown or grown Partially plants. of portions lower on bugs Immature plants. on ground below or above either feeding back. middle of stripe across a white with blackish to reddish are 1/8 inch insect about Adult wings, whitish for except black Adult less. or long 8. May to June on on June to 8. May seedling plants 7. May to June on on June to 7. May seedling plants Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table crop year/ of Time stage growth Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table crop year/ of Time stage growth 9. May to June on on June to 9. May seedling plants 10. May to June on on June to 10. May 6-inch seedlings to plants 84 | Insect Management Insect Management | 85 Fall army army Fall cattail worms, caterpillars Greenbugs* Corn leaf aphids* Probable Probable insect Probable insect Probable Sorghum webworm midge Sorghum Corn earworm Region-wide Region-wide Region-wide Distribution Distribution eastern In more areas, in common southeast the eastern In more areas, in common southeast the - com More in the mon southern the half of region Holes in leaves. Occasionally, plants very ragged. Damage often often very Damage ragged. plants Occasionally, in leaves. Holes fields. late-planted on severe more Lower leaves shiny and sticky; excessive honeydew deposit. deposit. honeydew sticky; and excessive shiny leaves Lower of leaves. on underside soft-bodied green, Light insectspresent present. are colonies where leaves on develop Reddish areas to allowed is and develops infestation heavy die where Leaves persist. Leaves shiny and syrupy, excessive honeydew present, aphids aphids present, honeydew excessive syrupy, and shiny Leaves also skins cast Whitish the plant. of portions in upper present blotches. reddish with yellow leaves Some present. frequently Description Description Small, light brown, fuzzy striped worms present in heads of of in heads present fuzzy striped worms brown, light Small, when full grown long 1/2 inch about sorghum, appear Heads the head. of more part or on Seeds develop to fail present, occasionally maggots red or orange Tiny beto "blasted." microscope under except visible not generally but begins usually Infestation head. in the developing grain Destroys to 1/4 in size from range Worms bloom. after shortly or during Larva in length. 1 1/2 inches possessthe a series stripes on of almost to pinkish, be greenish, may color predominant body, color brown light uniform capsule Head blackish. 13 June July, July, 13 June whorl August: stage 12. June, July July 12. June, whorl August: stage 11. June, July, July, 11. June, whorl August: stage Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table crop year/ of Time stage growth Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table crop year/ of Time stage growth 14. August, 14. August, September: during stage bloom 15. August September: during stage bloom 16. August, September 86 | Insect Management Insect Management | 87 Probable insect Probable chinch False bugs Probable insect Probable Grasshoppers mites Spider bugs* Chinch Distribution Region-wide Distribution Region-wide common More in the High can but Plains, in the be found Central Plains Eastern Plains Description Small, grayish insects similar in size and shape to chinch chinch to shape insects in size and similar grayish Small, of developing feedingheads in the different, is color but bugs, sorghum. Description margins. field particularly around leaves, on feeding Visible seeds in the head. developing on feeding of signs Occasional of signs leaves; lower of yellowing and browning Discoloration, "crawling Tiny leaves. affected of underside on webbing light also sometimes present. Greenbugs be present. specks" may headsis of poor occasional filling stress; of signs showing Plant lower on insects present blackish to reddish of Clusters visible. the stalk. of portions Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table crop year/ of Time stage growth 20. July, August, August, 20. July, September Insects of Frequent Concern in Sorghum Frequent 12 Cont. of Insects Table year/ of Time stage growth crop August 17. July, August 18. July, August, 19. July, September 88 | Diseases Diseases | 89 Diseases

Diseases of grain sorghum, like those of other

crops, vary in severity from year to year and t. from one locality or field to another, depending upon environment, causal organism(s) and host (plant) resistance. Estimates of annual sorghum yield losses to diseases in the Central Great Plains average less than 10%. Management pretreated comes All sorghum in aid fungicides with that Efficiency management. these often is chemicals of periods long of decreased by early and poor germination conditions. growth - goodSelect with stand hybrids continous Avoid ratings. ability fertilize adequately cropping, insects to loss leaf avoid and to tends disease. Hail foliar or stalk ro intensify

The total eradication of disease in sorghum is not economically feasible, so growers must try to minimize losses using an integrated pest management system. Planting resistant hybrids, provid- ing optimum growing conditions, rotating with other crops, burying infested debris, proper seedbed preparation and seed placement and accurate Occurrence - follow noticeable Most periods of prolonged ing after just weather wet cool, in poorly and planting may Fusarium soil. drained in froughty, be a problem soils. sandy by Disease favored is and moisture abundant temperatures moderate head initiation. following application of herbicides and insecticides are all - practices that can be used to minimize disease losses.

Although sorghum is susceptible to many diseases, there are only a few which cause or have the immediate potential to cause economic losses in the Central Great Plains on a regular basis. Sorghum is also susceptible to many physiologi- Symptoms stands. Seeds Thin uneven emergence to prior rot may after die back may plants or show may Plants emergence. to red with growth stunted roots. black plants. of death Premature consider show Roots usually stalk is tissue Infected rot. able dark to salmon with discolored predominating. often hues red cal leaf spots. These can be easily confused with a number of commonly occurring foliar diseases so caution should be taken in making a diagnosis. University plant disease diagnostic laboratories are available to assist in making positive disease identifications. Disease Cause and Seed Seedling and Rots Blights Pythium Blight Blight Fusarium Stalk Rots Stalk Rot Fusarium bulletin See extension of "Stalk Rots L-741, Sorghum" Corn and 90 | Diseases Diseases | 91 Management Many rotation. Crop are hybrids resistant available. hybrids. Resistant Many rotation. Crop are hybrids resistant available. Management - resis more are hybrids Some plant Reduce others. that tant drought avoid to populations hybrids Later-maturing stress. escape infection. often resistant Many rotation. Crop available. are hybrids Occurrence prolonged during prevalent Most weather. periods humid warm, of - in the grow late appears Usually early or August season (late ing warm, by Favored September). losses Significant weather. moist rare. are blight. leaf northern corn as Same in growing occurs late Usually maturing. is season the crop as losses occur. if any, Little, Occurrence occur to in apt Most drought- shallow, or light Disease soils. stressed may in scattered only be present the field. of areas are usually leaves Oldest most and first attacked losses of Yield extensively. been have more 30% or recorded. Disintegration of the lower the lower of Disintegration small, stalk numerous with - bodies scat black (sclerotia) throughout. tered Symptoms may that spots Elongated with severalextend inches orange to yellow broad, A sooty-like growth margins. present generally is (sclerotia) the lesion. of the underside on Symptoms elliptical more) or (2 inches Large reddish- and centers gray with spots sooty to similar Very borders. tan sclerotia. without stripe but blister-like or pustules Small brown leaf lower and the upper on growths leaf. the lowest surfaces on starting 1/4 lesions, rectangular purple, Dark cast a grayish having longer, and inch production. spore during 1 Charcoal Rot Charcoal bulletin See extension L-741 DiseasesFoliar Caused Fungi by Disease Cause and Sooty Stripe Disease Cause and Corn Leaf Northern Blight Rust Leaf Spot Gray 92 | Diseases Diseases | 93 Management Rotation. Crop hybrids current Most the to resistant are necrotic severe more symptoms. Management Many rotation. Crop are hybrids resistant available. Many rotation. Crop are hybrids resistant available. rotation. Crop - Occurrence Very common during warm, warm, during common Very weather. humid insects, carried is mostly by Virus aphid. lean corn and greenbug in Johnson overwinters MDMV grass. Occurrence where in areas prevalent Most alter periods high humidity of dry periods. relatively with nate prolonged during severe Most periods high humidity. of bacterial disease. common Most humid cool, during Prevalent weather. Symptoms Narrow, water-soaked, translucent translucent water-soaked, Narrow, 6 1 to wide by 1-8 inch about streaks several After in length. days, inches red. turn lesions might (alternating patterns Mosaic leaves. whorl on areas) green dark and A, Stain 60° F for Cool (below nights red cause B) may Strain 70° F for below a blight. resembling areas necrotic and Seed be be may delayed. may Flowering underdeveloped. Symptoms 1/8 to spots elliptical to circular Small, the Depending on in diameter. 1/4 inch red be orange, tan, may lesions hybrid, blackish-purple. or - alterna bands reddish-purple Circular, areas colored straw or tan with tion or zonate, a concentric which give diameter Lesion appearance. bull's-eye several extend inches. may stripes tan or reddish narrow, Long, Lesions hybrids. upon depending Shiny, veins. between confined usually generally exudates from crusty spots leaves. of underside on found 2 Disease Cause and Bacterial Streak DiseasesVirus Dwarf Mosaic Maize (MDMV-A) Virus Mosaic Sugarcane (MDMV-B) Virus Disease Cause and Leaf Spot Zonate DiseasesFoliar Caused Bacteria by Bacteria Stripe 94 | Diseases Diseases | 95 Management hybrids current Most the more to resistant necrotic severe symptoms. Rotation. Crop are hybrids Resistant pathotype to available 1. the where areas Avoid disease a recurring is problem. Fungicide application at at application Fungicide be can made, pollination only usually are but in hybrid economical fields. seed production a rain after right Harvesting off washed temporarily has prevent may the honeydew harvesting of the clogging equipment. not are Chemical controls resistant Utilize effective. hybrids. Management Occurrence and in eastern common Most the of areas production southern Infections Plains. Central Great - satu under take place generally the within soil conditions rated of emergence. fewweeks first when flooding severe Most seedbedsoccurs on young or seedlings, especially in poorly soils. clay or drained Observed when the crop matures Observed matures when the crop - com Most dough. soft during weather. wet cool, during mon Occurs only sporadically in the sporadically Occurs only The fungus Plains. Central Great unfertilized infects through only in occurs late only usually It ovaries. - the season tem when colder of late affect pollination peratures developing late or sorghum planted tillers. seedling stage; infected at are Plants until apparent not are symptoms severe More stage. heading boot or southwest and in south-central Plains. the Central Great of areas Occurrence Exudation of sweet, sticky sticky sweet, of Exudation the infected from "honeydew" Honeydew occurs. flowers solid or leaves onto drips that powdery lass a white, produces Ovary conditions. moist during a white to be converted may between the visible fungal mass glumes. the allhead is of A portion or galls. smut by replaced Symptoms Symptoms in leaves stripes on white and green Vivid - shred Leaves summer. early or spring late left. are veins leaf only until wind ded by sterile. partially completely or Heads stiff, become rubbery leaves colored Light glumes appear, heads If twisted. and top" "crazy to give proliferated often are symptom. Red to black lesions develop on panicle panicle on develop lesions Red black to seed dull becomes As shrinks it branches. in color. 3 Sorghum Ergot Sorghum Smut Heat Disease Cause and Disease Cause and Downy Sorghum Mildew Downy Crazy Top Mildew Small Seed MDMV Primarily Other Sorghum Diseases 96 | Diseases Harvesting| 97

1There are many foliar diseases caused by fungi that can occur on sorghum including sooty stripe, rust and northern corn Harvesting leaf blight. Sooty stripe and rust can cause economic losses Grain sorghum demands the best combine to occur in some years and on some hybrids. Registration of operators. Most crops have a specific problem strobiluron fungicides is in progress. If and when they be- (such as header loss in soybeans), but grain come available, the economics of their use should be carefully sorghum can have difficulties at nearly every considered since they would likely be profitable only on the point in the combining process. These problems most susceptible hybrids and under the most severe disease are compounded by the fact grain sorghum pressure. Management of these diseases should primarily rely often ripens unevenly. In good-standing grain on selecting resistant hybrids and cultural practices such as sorghum, losses can usually be kept to 5% of the crop rotation and the removal of residue where soil erosion is yield, but only careful adjustment and operation not a problem. of the combine makes that possible. Additional time and effort will be required, but expenses are 2Bacterial leaf diseases have not been shown to cause yield already in the crop, and every extra bushel saved losses under Central Great Plains conditions, but they are is clear profit. generally present in some fields every year, particularly under wet, humid conditions. There are five types of harvest loss: Preharvest loss is typically weather-related and 3In the Central Great Plains, only seedling blights, stalk rots can be minimized by timely harvesting. Crops and sooty stripe are likely to cause economic yield losses on a left in the field too long can be damaged by birds regular basis. Crazy top downy mildew and sorghum downy or field shatter. Severe weather before or during mildew occasionally cause significant yield loss in individual harvest can cause lodging, which makes the crop fields or small areas of a field in years with excessive moisture difficult to harvest. early in the season, but they are not a widespread problem. Sorghum ergot infection is rare in the Central Great Plains, Combine size, crop acreage and available workdays but when it does occur it can cause significant harvesting dictate timeliness. Combines should be large problems because the sticky honeydew can bind up combines, enough to harvest the crop in acceptable time. If forage cutters and augers. this is not economically feasible, custom harvesting is an option. Another option is harvesting earlier, but this must be balanced against greater drying costs. Generally, grain sorghum can be combined whenever the moisture content is less than 30%. Header loss includes shattered kernels, dropped 98 | Harvesting Harvesting| 99 heads and uncut heads. If a conventional reel is concave clearance than harvesting sorghum at used, the speed of the reel bats should be slightly lower moisture contents. faster than ground speed. Operating the reel too fast will increase shatter losses, while operat- Shoe loss is grain carried or blown across the ing too slow will cause dropped heads. Several shoe. Kansas State University research indicates attachments are available to improve gathering it may be the most serious and most overlooked efficiency. Flexible guard extensions on grain source of harvesting loss in grain sorghum. In platforms substantially reduce gathering losses in most modern combines, the shoe (and not the standing-crop conditions. Row attachments on cylinder) is the first component of the combine to grain platforms or using a row-crop head reduces overload in grain sorghum. If the combine opera- losses in both standing and lodged conditions. tor pushes the machine as fast as the cylinder can go, the shoe is usually losing large quantities Cylinder loss, or unthreshed grain can be a major of grain. In one series of tests, a 33% increase problem with grain sorghum. It is often neces- in ground speed caused shoe loss to increase by sary to compromise between adequate threshing more than 4% of the total yield. Shoe losses also and excessive kernel cracking. Cracking can be are increased when operating on hillsides. The caused by either too little clearance or too fast amount of air blown on the shoe is important, as cylinder speed, but speed is usually the cause. is the opening of the louvers. Closing the chaffer Severe threshing action can pulverize the stalks louvers will increase the air velocity through the and overload the cleaning shoe and walker. It is opening; air opening (or fan speed) should be often necessary to leave up to 2% of the grain in reduced as the louver opening is closed. the head to achieve the best overall harvesting results. Walker loss can be caused by excessive speed also, but in most combines the walkers overload after the In high-moisture grain sorghum, cylinder speed shoe; therefore, walker overloading is of secondary and concave-clearance adjustments are critical. importance when combining grain sorghum. As the head passes through the cylinder area, rolling it (rather than a shearing) provides maxi- How to Measure Combine Loss: Ground counts mum threshing with minimum kernel and stalk are tedious work, especially in grain sorghum. damage. The cylinder-concave clearance should Nevertheless, they offer a reasonably accurate be set so the stalks are not crushed, and cylinder idea of how much grain is being lost. As a rule speed should be increased until thorough thresh- of thumb, 17 to 20 kernels per square foot are ing occurs. This often requires wider cylinder- equivalent to one bushel per acre. 100 | Harvesting Harvesting| 101

To accelerate ground counts, a 1 square foot by subtracting the header loss from the total frame may be constructed from heavy wire. It machine loss. It is sometimes difficult to deter- is best to take at least three ground counts at mine if the loss is being carried over the walkers each location. When making ground counts for or blown across the shoe. Provided the combine kernels, look for lost heads. One 10-inch head in does not use a straw chopper, the loss can often a 10 ft. X 10 ft. area is approximately one bushel be pinpointed by observing the shoe while the per acre. combine is operating.

Total loss can be checked behind the combine. Combine loss monitors can indicate changing Make ground counts on 1 square foot areas in harvest conditions. They should be set to indicate three locations uniformly spaced across the a representative loss. If time is not spent setting header width, with one count being made in the monitor, the reading is of little value. the discharge area of the combine. Average the counts and divide by 20 to get bushels per acre. If the result is 5% or less of the total yield, losses are Determining harvest losses within reasonable limits.

If the total loss was more than 5%, the next step is to determine the pre-harvest loss. Check this in front of the combine in the standing sorghum. Take three counts on one square foot areas, then average them and divide by 20. Subtract the preharvest loss from the total loss to determine the net machine loss. If the net machine loss is more than 5%, determine where the loss is occurring.

Header loss can be determined by backing the combine a few feet and taking ground counts between the header and the uncut sorghum. The difference between the header count and preharvest count is the net header loss.

Cylinder and separation loss can be determined 102 | Sorghum Economics Sorghum Economics | 103

insurance proceeds. Production cost per acre Sorghum Economics includes cash costs, depreciation and opportunity costs on owned assets, but excludes hired labor Two questions each producer must answer when and unpaid operator and family labor. Thus, the selecting crops and the acreage of each crop to bottom line number represents a residual return produce are: (1) Will the crop be profitable? and accruing to labor and management. An indi- (2) Will the crop add more to farm profitability vidual that owns their ground would have higher than other crops? Information needed to answer per acre revenue and cost than that shown. these questions include crop yield, crop price, government payments, crop insurance proceeds More information pertaining to whole-farm and and production costs. enterprise profitability can be obtaining by click-

ing on “KFMA” on the following web site: www. Production costs are typically broken down into agmanager.info/kfma. variable and fixed costs. Variable costs vary with the level of production and include seed, fertilizer, herbicide, insecticide, fuel and utilities, repairs, insurance and miscellaneous items such as storage and marketing. Fixed costs do not vary with the level of production and include depreciation, interest on noncurrent assets, taxes and land charges.

Historical revenue and production costs are shown for non-irrigated grain sorghum in eastern, central, and western production regions (Table 13). The northwest production region information represents no-till production. Data for the other regions represent mixed tillage operations. The historical revenue and production costs illustrated represent the operator’s share of revenue and costs. Gross income per acre includes revenue from grain sorghum production and other revenue such as patron- age dividends, government payments and crop 104 | Sorghum Economics References | 105 References

Table 13. Net Return to Labor and Management for Non- Irrigated Grain Sorghum for the Eastern and Central Plains 1. FAO. 2007. Global Production of Grain Sorghum Growing Regions. sorghum. Online. North- South- North South east east Central Central http://www.fao.org/docrep/T0818E/ Yield per acre 95 75 90 82 T0818E03.htm#Chapter%202%20-%20Pro- Revenue from Corn 254.39 157.06 204.22 169.29 duction%20and%utilization Production Other Revenue 48.33 33.98 26.21 42.17 2. U.S. Grains Council. 2008. Sorghum. GROSS INCOME PER $302.72 $191.04 $230.43 $211.46 ACRE Online. Seed 11.01 12.04 11.89 15.32 http://www.grains.org/sorghum Fertilizer and Limes 43.68 40.53 39.88 35.86 Herbicide and Insecticide 23.15 19.43 27.29 21.72 3. National Grain Sorghum Producers Associa- Fuel and Utilities 19.81 16.94 15.81 16.99 tion. Online. Repairs and Machine Hire 32.9 19.39 20.65 20.49 http://www.sorghumgrowers.com/sor- Crop Insurance 6.92 5.60 7.84 5.04 ghum%20101.html General Farm Insurance 5.22 2.77 3.03 2.61 Miscellaneous 3.64 6.37 2.99 4.01 4. Kansas Grain Sorghum Producers Asso- Depreciation 19.84 19.24 16.53 18.27 ciation. 2008. Kansas Ethanol Production. Interest 19.24 14.22 14.02 14.16 Online. Taxes 5.85 2.88 3.52 3.66 http://www.ksgrains.com/ethanol/kseth.html Land Charges 70.03 18.65 30.29 20.29 PRODUCTION COST PER $261.08 $174.98 $193.74 $178.42 ACRE 5. U.S. EPA. 2009. Crop Production. Online. NET RETURN TO LABOR $41.64 $16.07 $36.70 $33.04 http://www.epa.gov/oecaagct/ag101/ AND MANAGEMENT printcrop.html Note: Table above shows revenue and cost items based on Kansas Farm Management Association enterprise data for 6. Figure 2. Pocket Guide to Crop Develop- the 2004-2008 period and include only the operator's share of ment: Illustrated Growth Time lines for revenue and costs. Corn, Sorghum, Soybean, and Wheat. 2003. University of Illinois Extension Publication #C1389. 106 | Calculations & Conversions Calculations & Conversions | 107

Calculations & Conversions Reduce irregularly shaped areas to a combination of rectangles, circles and triangles. Calculate the area of each and add them together to get the total area.

h Area of a rectangle or square = dt wi length x width length 1 1 ht h h dt dt heig wi wi Area of a circle = 3.1416 x base length diameter radius squared; or 0.7854 x 2 length1 s diameter squared rad iu Circumference of a circle = Example: If b = 25’, h = 25’, L1 = 30’, W1 = 42’, L2 = 33’, W2 = 3.1416 x diameter; or 6.2832 x 31’, then the equation is: Area = ((b x h) ÷2) + (L x W ) +(L x W ) radius 1 1 2 2 = ((25 x 25) ÷2) + (30 x 42) + (31 x 33) = 2595 sq. ft. ht Area of triangle = base x height heig ÷ 2 base Another way is to draw a line down the middle of the property for length. Measure from side to side at several points along this line. Use the average of these values as the width. Calculate the

ht Volume of rectangle box or area as a rectangle. heig cube = length x width x height

width d length c h f g radius e a b Volume of a cylinder = 3.1416 length x radius squared x length

Example: If ab = 45’, c = 19’, d = 22’, e = 15’, f = 17’, g = 21’, h = 22’, then the equation is:

ht Area = (ab) x (c + d + e + f + g + h) ÷ 6 Volume of cone = 1.0472 x heig = (45) x (19 + 22 + 15 + 17 + 21 + 22) ÷ 6 radius radius squared x height = 870 sq. ft. 108 | Calculations & Conversions Calculations & Conversions | 109

Conversion Factors Cup x8 Fluid ounces Acres (A) x0.405 Hectares Cup x236.5 Milliliters Acres x43,560 Square feet Cup x0.5 Pint Acres x4047 Square Meters Cup x0.25 Quart Acres x160 Square rods Cup x16 Tablespoons Acres x4840 Square yards Cup x48 Teaspoons Bushels (bu) x2150.42 Cubic inches ºCelsius (ºC) (+17.98)x1.8 Fahrenheit Bushels x1.24 Cubic feet ºFahrenheit (ºF) (-32)x0.5555 Celsius Bushels x35.24 Liters Fathom x6 Feet Bushels x4 Pecks Feet (ft) x30.48 Centimeters Bushels x64 Pints Feet x12 Inches Bushels x32 Quarts Feet x0.3048 Meters Bushel Sorghum 56 pounds Feet x0.33333 Yards Feet/minute x0.01667 Feet/second CaCO3 x0.40 Calcium Feet/minute x0.01136 Miles/hour CaCO3 x0.84 MgCO3 Fluid ounce x1.805 Cubic inches Calcium (ca) x2.50 CaCO3 Centimeters (cm) x0.3937 Inches Fluid ounce x2 Tablespoons Centimeters x0.01 Meters Fluid ounce x6 Teaspoons Cord (4’x4’x8’) x8 Cord feet Fluid ounce x29.57 Milliliters Cord foot (4’x4’1’) x16 Cubic feet Furlong x40 Rods Cubic centimeter (cm3) x0.061 Cubic inch Gallons (gal) x269 Cubic in. (dry) Cubic feet (ft3) x1728 Cubic inches Gallons x231 Cubic in. (liq.) Cubic feet x0.03704 Cubic yards Gallons x3785 Cubic cms Cubic feet x7.4805 Gallons Gallons x0.1337 Cubic feet Cubic feet x59.84 Pints (liq.) Gallons x231 Cubic inches Cubic feet x29.92 Quarts (liq.) Gallons x3.785 Liters Cubic feet x25.71 Quarts (dry) Gallons x128 Ounces (liq.) Cubic feet x0.084 Bushels Gallons x8 Pints (liq.) Cubic feet x28.32 Liters Gallons x4 Quarts (liq.) Cubic inches (in3) x16.39 Cubic cms Gallons of Water x8.3453 Pounds of Wa Cubic meters (m3) x1,000,000 Cubic cms Grains x0.0648 Grams Cubic meters x35.31 Cubic feet Grams (g) x15.43 Grains Cubic meters x61,023 Cubic inches Grams x0.001 Kilograms Cubic meters x1.308 Cubic yards Grams x1000 Milligrams Cubic meters x264.2 Gallons Grams x0.0353 Ounces Cubic meters x2113 Pints (liq.) Grams/liter x1000 Parts/million Cubic meters x1057 Quarts (liq.) Hectares (ha) x2.471 Acres Cubic yards (yd3) x27 Cubic feet Hundred wt (cwt) x100 Pounds Cubic yards x46,656 Cubic inches Inches (in) x2.54 Centimeters Cubic yards x0.7646 Cubic meters Inches x0.08333 Feet Cubic yards x21.71 Bushels Inches x0.02778 Yards Cubic yards x202 Gallons K2O x0.83 Potassium (K) Cubic yards x1616 Pints (liq.) Kilogram (kg) x1000 Grams (g) Cubic yards x807.9 Quarts (liq.) Kilogram x2.205 Pounds 110 | Calculations & Conversions Calculations & Conversions | 111

Kilograms/hectare x0.8929 Pounds/acre Parts per million x0.001 Grams/liter Kilometers (K) x3281 Feet Parts per million x0.0001 Percent Kilometers x1000 Meters Parts per million x1 Milligram/kg Kilometers x0.6214 Miles Parts per million x1 Milligram/liter Kilometers x1094 Yards Pecks x0.25 Bushels Knot x6086 Feet Pecks x537.605 Cubic inches Liters (l) x1000 Milliliters Pecks x16 Pints (dry) Liters x1000 Cubic cms Pecks x8 Quarts (dry)

Liters x0.0353 Cubic Feet Phosphorus (P) x2.29 P2O5 Liters x61.02 Cubic inches Pints (p) x28.875 Cubic inches Liters x0.001 Cubic meters Pints x2 Cups Liters x0.2642 Gallons Pints x0.125 Gallon Liters x2.113 Pints (liq.) Pints x473 Milliliters Liters x1.057 Quarts (liq.) Pints x32 Tablespoons Liters x0.908 U.S. dry quart Pints (dry) x0.015625 Bushels Magnesium (mg) x3.48 MgCO3 Pints (dry) x33.6003 Cubic inches Meters (m) x100 Centimeters Pints (dry) x0.0625 Pecks Meters x3.281 Feet Pints (dry) x0.5 Quarts (dry) Meters x39.37 Inches Pints (liq.) x28.875 Cubic inches Meters x0.001 Kilometers Pints (liq.) x0.125 Gallons Meters x1000 Millimeters Pints (liq.) x0.4732 Liters Meters x1.094 Yards Pints (liq.) x16 Ounces (liq.) MgCO3 x0.29 Magnesium (Mg) Pints (liq.) x0.5 Quarts (liq.) 3 3 MgCO x1.18 CaCO Potash (K2O) x0.83 Potassium (K) Miles x5280 Feet Potassium (K) x1.20 Potash (K2O) Miles x1.69093 Kilometers Pounds (lb) x7000 Grains Miles x320 Rods Pounds x453.5924 Grams Miles x1760 Yards Pounds x16 Ounces Miles/hour x88 Feet/minute Pounds x0.0005 Tons Miles/hour x1.467 Feet/second Pounds x0.45369 Kilograms (kg) Miles/minute x88 Feet/second Pounds of water x0.01602 Cubic feet Miles/minute x60 Miles/hour Pounds of water x27.68 Cubic inches Milliliter (ml) x0.034 Fluid ounces Pounds of water x0.1198 Gallons Ounces (dry) x437.5 Grains Pounds/acre x1.12 Kilograms/ha Ounces (dry) x28.3495 Grams Quarts (qt) x946 Milliliters Ounces (dry) x0.0625 Pounds Quarts (dry) x0.03125 Bushels Ounces (liq.) x1.805 Cubic inches Quarts (dry) x67.20 Cubic inches Ounces (liq.) x0.0078125 Gallons Quarts (dry) x0.125 Pecks Ounces (liq.) x29.573 Cubic cms Quarts (dry) x2 Pints (dry) Ounces (liq.) x0.0625 Pints (liq.) Quarts (liq.) x57.75 Cubic inches Ounces (liq.) x0.03125 Quarts (liq.) Quarts (liq.) x0.25 Gallons Ounces (oz.) x16 Grams Quarts (liq.) x0.9463 Liters

P2O5 x0.44 Phosphorus (P) Quarts (liq.) x32 Ounces (liq.) Parts per million (ppm) x0.0584 Grains/gallon Quarts (liq.) x2 Pints (liq.) 112 | Calculations & Conversions Appendices | 113

Rods x16.5 Feet Square feet (ft2) x0.000247 Acres Appendices Square feet x144 Square inches Square feet x0.11111 Square yards Square inches (in2) x0.00694 Square feet a. The Sorghum Plant Square meters (m2) x0.0001 Hectares (ha) Square miles (mi2) x640 Acres Sorghum grain is found on the panicle, com- Square miles x28,878,400 Square feet Square miles x3,097,600 Square yards monly referred to as the head. The panicle Square yards (yd2) x0.0002066 Acres consists of a central axis with whorls of main Square yards x9 Square feet branches, each of which contains secondary and Square yards x1296 Square inches Tablespoons (Tbsp) x15 Milliliters at times, tertiary branching. The length of the Tablespoons x3 Teaspoons branches allows for a wide range of shapes and Tablespoons x0.5 Fluid ounces sizes in sorghum and for sorghums with very Teaspoons (tsp) x0.17 Fluid ounces Teaspoons x0.333 Tablespoons open panicles or sorghums with very compact Teaspoons x5 Milliliters panicles. The branches carry the racemes of the Ton x907.1849 Kilograms spikelets where the grain is found (see Figure 9). Ton x32,000 Ounces Ton (long) x2240 Pounds The panicle emerges at boot from the flag leaf Ton (short) x2000 Pounds sheath. U.S. bushel x0.3524 Hectoliters U.S. dry quart x1.101 Liters U.S. gallon x3.785 Liters Yards (yd) x3 Feet Yards x36 Inches Yards x0.9144 Meters Yards x0.000568 Miles 114 | Appendices Appendices | 115

black layer is formed between the germ and the endosperm, some 25 to 40 days after flowering. Seeds are normally harvested 10 to 20 days after black layer when moisture content is generally 15 percent or less. Black layer can be seen at the base of the grain where it attaches to the rachis branch and indicates that the grain is physiologically mature. Seeds are made up of three major components, the endosperm, embryo, and pericarp (Figure 14). All sorghums contain a testa, which separates the pericarp from the endosperm. If the testa is pigmented, sorghum will contain tannins, if not, the grain is free of tannins. None of the commercial U.S. grain sorghums have a pigmented testa and all are said to be free of tannins.

Fig. 9. The panicle of Sorghum bicolor subsp. bicolor which consists of the inflorescence and spikelets. 1. Part of panicle: a = internode of rachis; b = node with branches; c = branch with several racemes. 2. Raceme: a = node; b = internode; c = sessile spikelet; d = pedicel; e = pedicelled spikelet; f = terminal pedicelled spikelets; g = awn. 3. Upper glume: a = keel; b = incurved margin. 4. Lower glume: a = keel; b = keel wing; c = minute tooth terminating keel. 5 Lower lemma: a = nerves. 6. Upper lemma: a = nerves; b = awn. 7. Palea. 8. Lodicules. 9. Flower: a = ovary; b = stigma; c = anthers. 10. Grain: a = hilum. 11. Grain: a = embryon-mark; b = lateral lines. (Drawing by G. Atkinson. Reprinted, with permission, from J. D. Snowden, 1936, The Cultivated Races of sorghum, Adlard and Son, London. Copyright Bentham - Moxon Trust - Fig. 10. Sorghum grain, showing the pericarp (cutin, epicarp, Royal Botanical Gardens, Kew, England. mesocarp, cross cells, tube cells, testa, pedicel, and stylar area (SA)), endosperm (aleurone layer, corneous and floury), and Seeds begin developing shortly after flower- the germ (scutellum (S) and embryonic axis (EA). Adapted ing and reach physiological maturity when the from L. W. Rooney and Miller, 1982). 116 | Appendices Appendices | 117 b. Photos

Photos 4-6 above. Sorghum photos above are from a last post- emergence application of herbicides and showing evidence of Photos 1-3 above. Sorghum at top had no herbicides applied crop injury. Sorghum on the left treated with one pint of 2,4-D and yielded 20 bushels per acre. Sorghum in the center had Ester. Note the growth regulator response, leaning sorghum etc. post-emergence broadleaf weed control only and yielded 82 Sorghum in the center was with 0.5 fl oz of Aim EC + nonionic bushels per acre. The sorghum on the right received pre- surfactant. Note the leaf burn to sorghum leaves. Sorghum on emergance broadleaf and grass weed control and yielded 130 the right was treated with 0.005 oz of Ally + 8 fl oz of 2,4-D bushels per acre. amine, Slight chlorosis to some leaves and slight 2,4-D injury are visible. 118 | Appendices Appendices | 119

Photo 7. Iron Deficiency Photo 9. Corn Leaf Aphid

Courtesy of International Plant Nutrition Institute Photo 8. Greenbug Photo 10. Yellow Sugarcane Aphid* 120 | Appendices Appendices | 121

Photo 11. Corn Earworm** Photo 13. Sorghum Webworm*

Photo 12. Fall Armyworm* Photo 14. Sorghum Midge*

**Used with permission of USDA-ARS *Used with permission of Dr. Pendelton, West Texas A&M University 122 | Notes Notes | 123

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______132 | Notes Sorghum Facts

______Sorghum is the fifth most important cereal crop in the world. It is used in a wide range of applications, such as ethanol production, animal feed, pet food, food products, ______building material, brooms and other industrial uses. Sorghum originated in Northeast Africa and spread to Asia, Europe and the Western Hemisphere. In the United States, ______sorghum is the second most important feed grain for biofuel production and is known for its excellent drought tolerance and superior adaptability to different environments. The first written record of sorghum in the U.S. traces to a letter that ______Benjamin Franklin wrote in 1757.

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The United Sorghum Checkoff Program is an ______equal opportunity institution.

______All educational programs and materials are available without discrimination on the basis of race, color, national origin, sex, religion, age, ______disability, sexual orientation, marital, family, or parental status, receipt of public assistance, political beliefs or protected genetic ______information.

______All pesticide information contained within conforms to federal and state regulations at the time of writing. Consult the label associated ______with the pesticide for current use precautions and restrictions. Publisher does not warrant commercial products and is not responsible for ______any errors in this guide. United Sorghum Checkoff Program

DISCLAIMER Some of the information presented in this handbook is specific to the High Plains. Producers in all states should check with their own Cooperative Extension Service or county agents for state-specific information. Reference to products in this publication is not intended to be an endorsement of a particular product to the exclusion of others which may have similar uses. Any person using products listed in this handbook assumes full responsibility for their use in accordance with current label or information directions of the manufacturer.