Vegetable Production Using

o be competitive in today’s mar- ing on the thickness of . The linear high- What Are the ketplace, vegetable growers must density is used to reduce weight and Components of a strive continually for high qual- cost and is stronger than the same thickness of ity, superior yields, and extended low-density polyethylene. The mulch is Plasticulture production cycles that include spring either slick (smooth) or embossed with a dia- Tand fall crops. Plasticulture is a management tool mond-shaped pattern. Thispattern helps reduce Vegetable System? that enables vegetable producers to realize greater expansion and contraction, which results in the returns per unit of land. Such a system may offer loosening of the mulch from the raised bed. The many benefits: raised bed is generally 4 to 6 inches (10 to 15 cm) William James Lamont, Jr.1 •Earlier crop production (7 to 21 days earlier) high and 30 inches (76 cm) wide and has a slope •Higher yields per acre (two to three times higher) of 1.25 inches (3.2 cm) from the center to the edge. •Cleaner and higher quality produce Soil under a raised bed will warm up quicker in the •More efficient use of resources spring and also will shed excess water off the bed •Reduced leaching of fertilizers, especially on into the row middles, thus keeping the crop plants lighter, sandy soils drier and preventing deterioration in quality of the Additional index words. plastic , •More efficient use of fertilizer inputs through product. drip , fertigation, season- fertigation technology Plastic mulches directly impact the micro- extending technology •Reduced soil and wind erosion climate around the plant by modifying the radia- •Potential decrease in the incidence of disease tion budget (absorbitivity vs. reflectivity) of the •Better management of certain insect pests surface and decreasing the soil water loss (Liakatas •Fewer problems et al., 1986; Tanner, 1974). The color of a mulch Summary. Plasticulture, simply defined, is •Reduced soil compaction and elimination of root largely determines its energy-radiating behavior a system of growing crops wherein a pruning and its influence on the microclimate around a significant benefit is derived from using •Opportunity to double- or triple-crop with maxi- vegetable plant. Color affects the surface tempera- products derived from plastic polymers. mum efficiency ture of the mulch and the underlying soil tempera- The discovery and development of the To realize these benefits, one needs to inte- ture. Ham and Kluitenberg (1994) found that the polyethylene polymer in the late 1930s, grate the components of a plasticulture system. degree of contact between the mulch and soil, and its subsequent introduction in the The components include plastic mulches, drip often quantified as a thermal contact resistance, early 1950s in the form of plastic films, irrigation, chemigation/fertigation, soil fumiga- can affect greatly the performance of a mulch. If an mulches, and drip-irrigation tubing and tion or solarization (may or may not be needed air space is created between the and tape, revolutionized the commercial depending on location), windbreaks, stand estab- the soil by a rough soil surface, soil warming can production of selected vegetable crops lishment technology, season-extending technol- be less effective than would be expected from a and gave rise to plasticulture. The later ogy, pest management, cropping strategies, and particular mulch. discovery of other polymers, such as marketing. The plasticulture system can be used The soil temperature under a plastic mulch , polyproplene, and effectively by growers with small or large acreage. depends on the thermal properties (reflectivity, , and their use in pipes, The basic principles and intensive management absorbitivity, or transmittancy) of a particular ma- fertigation equipment, filters, fittings and required to operate a plasticulture system suc- terial in relation to incoming solar radiation (Schales connectors, and row covers further cessfully are similar, regardless of the size of an and Sheldrake, 1963). Black plastic mulch, the extended the use of plastic components in operation. A component list for a 20-acre (8.1-ha) predominate color used in vegetable production, this production system. The plasticulture plastic mulch/ system is presented is an opaque blackbody absorber and radiator. system consists of plastic and nonplastic in Table 1. The crops that have shown significant Black mulch absorbs most UV, visible, and infra- components: plastic mulches, drip increases in earliness, yield, and/or fruit quality red wavelengths of incoming solar radiation and irrigation, fertigation/chemigation, with the use of plasticulture include muskmelon, reradiates absorbed energy in the form of thermal fumigation and solarization, windbreaks, tomato, pepper, cucumber, squash, eggplant, wa- radiation or long-wavelength infrared radiation. stand establishment technology, season- termelon, and okra. Other crops, such as sweet Much of the solar energy absorbed by black plastic extending technology, pest management, corn, snap bean, and pumpkin/decorative gourds, mulch is lost to the atmosphere through radiation cropping strategies, and marketing. cole crops, and herbs, have shown similar re- and forced convection. The efficiency with which sponses and may lend themselves to double- or black mulch increases soil temperature can be Department of Horticulture, Forestry and Recreation triple- cropping strategies. improved by optimizing conditions for transfer- Resources, Kansas State University, Manhattan, KS ring heat from the mulch to the soil. Because 66506-5506. Plastic mulches thermal conductivity of the soil is high relative to 1Associate professor. that of air, much of the energy absorbed by black Plastic mulches have been used commer- plastic can be transferred to the soil by conduction Contribution no. 96-317-J from the Kansas cially on vegetables since the early 1960s. Much of if contact is good between the plastic mulch and Agricultural Experiment Station, Manhattan. Mention of a trademark or proprietary product does not the early university research before 1960 was the soil surface. Soil temperatures under black ° constitute a guarantee or warranty of the product by conducted on the impact of color (black and clear) plastic mulch during the daytime are generally 5 F the Kansas Agricultural Experiment Station and does on soil and air temperature, moisture retention, (2.8 °C) higher at a 2-inch (5-cm) depth and 3 °F not imply its approval to the exclusion of other and vegetable yields (Emmert, 1957). Most plastic (1.7 °C) higher at a 4-inch (10-cm) depth com- products that may be suitable. mulches used in the United States are made of pared to those that of bare soil. The cost of publishing this paper was defrayed in part either linear low- or high-density polyethylene and In contrast, clear plastic mulch absorbs little by the payment of page charges. Under postal are 5 to 1.25 mil thick (0.012 to 0.031 mm), 48 to solar radiation but transmits 85% to 95%, with regulations, this paper therefore must be hereby 60 inches (122 to 152.4 cm) wide, and on rolls relative transmission depending on the thickness marked advertisement solely to indicate this fact. 2000 to 4800 feet (607 to 1463 m) long, depend- and degree of opacity of the polyethylene. The

150 HortTechnology ● July/Sept. 1996 6(3) Table 1. Components list for 20-acre (8.1-ha) plasticulture system.z

Component description Quantity Type unit Unit price ($) Total price ($) Engine and pump (14-hp engine and Berkley pump) 1 ls 4000.00 4000.00 24” media filter and fertilizer injector pr 3200.00 3200.00 Layflat, 4" 1800 ft. 1.01 1818.00 Layflat, 3" 1500 ft. 0.81 1215.00 Drip tape (7500'/Roll) 20 ea. 135.00 2700.00 Plastic mulch (1.0 mil black embossed 4000'/Roll) 40 rl 80.00 3200.00 Zone control/PRV valve, 3" 4 ea. 180.00 720.00 Insert tee, 4" 1 ea. 31.62 31.62 PVC tee (S × T), 4" × 3" 4 ea. 14.34 57.36 Insert ELL, 4" 2 ea. 21.25 42.50 Insert × slip adapter - 4" 6 ea. 11.26 67.56 PVC bush., 4" × 2" 2 ea. 5.35 10.70 PVC tee (S × T) - 3" 4 ea. 10.87 43.48 PVC nipple, 3" × 4" 8 ea. 5.52 44.16 Insert × slip adapter, 3" 8 ea. 8.92 71.36 Insert male adapter, 3" 8 ea. 5.30 42.40 PVC ELL (S × T), 3" 8 ea. 6.80 54.40 PVC bush., 3" × 2" 8 ea. 2.28 18.24 PVC nipple, 2" × 4" 10 ea. 1.49 14.90 Air release valve, 2" 10 ea. 27.00 270.00 PVC ELL, 2" 2 ea. 1.38 2.76 Hose clamp, 4" 14 ea. 1.72 24.08 Hose clamp, 3" 16 ea. 1.47 23.52 Tape × layflat connectors 480 ea. 0.95 456.00 Layflat hole punch 2 ea. 75.00 150.00 Subtotal 18,278.04 Tax 1% 182.78 Total 18,460.82 zOnly plastic mulch and drip irrigation components included. The plan assumes field to be level with surface water supply (pond) adjacent to field. System is basic with media filters, venuri injector, and 14-hp engine and pump. Additional equipment that should be cosidered includes secondary filters, additional pressure regulators, pressure gauges, and water meters. Water samples and field topography should be analyzed beefore actual drip design. No sales tax, freight, or field labor were included in the estimate. Source: Henry Johnson, Johnson Irrigation Co., Advance, N.C.

under surface of clear plastic mulch usually is a fumigant or because of the potential affect not only crop growth but also insect re- covered with condensed water droplets. This water weed growth. sponse to the plants grown on the mulch. Ex- is transparent to incoming shortwave radiation but Another family of mulches includes the wave- amples are yellow, red, and bluemulches, which is opaque to outgoing longwave infrared radiation, length-selective or photoselective mulches, which increased green peach aphid populations (Orzolek so much of the heat lost to the atmosphere from a selectively transmit radiation in some regions of and Murphy, 1993), especially the yellow color, bare soil by infrared radiation is retained by clear the electromagnetic spectrum but not in the pho- which has long been used in to plastic mulch. Thus, daytime soil temperatures tosynthetic wavelength (Loy et al., 1989). These monitor insects. Mulches with a printed silver under clear plastic mulch are generally 8 to 14 °F mulches absorb photosynthetically active radia- surface color have been shown to repel certain (4.4 to 7.8 °C) higher at a 2-inch (5-cm) depth and tion (PAR) and transmit solar infrared radiation, aphid species and reduce or delay the incidence of 6 to 9 °F (3.3 to 5.0 °C) higher at a 4-inch (10-cm) providing a compromise between black and clear aphid-borne viruses in summer squash (Lamont depth compared to those of bare soil. Clear plastic mulches. The infrared-transmitting (IRT) mulches et al., 1990). Similar to a white color mulch, the mulches generally are used in the cooler regions of afford the weed control properties of black mulch degree of opacity of a gray mulch may require a the United States, such as the New England states. but are intermediate between black and clear mulch herbicide or fumigant to be used to prevent weed Using clear plastic mulch will require the use of a in terms of increasing soil temperature. The color growth. Some of these colored mulches (blue and herbicide, soil fumigant, or solarization to control of these mulches can be blue-green (IRT-76, AEP red) have a dramatic impact on the soil tempera- . Industries Inc., Moonachie, N.J., or Climagro, tures, raising soil temperatures to 167 and 168 °F White, coextruded white-on-black or silver Leco Industries, Inc., Quebec, Canada) or brown (60.6 and 61.3 °C), respectively, at the 2-inch reflecting mulches can result in a slight decrease (Polyon-Barkai, Poly West, Encinitas, Calif.). These (5.1-cm) depth when the ambient air temperature in soil temperature [–2 °F (1.1 °C) at a 1-inch (2.5 mulches warm up the soil like clear mulch but was 104 °F (25 °C) (Lamont, unpublished data). cm) depth or –0.7 °F (0.4 °C) at a 4-inch (10-cm) without the accompanying weed problem. Photodegradable plastic mulch is one alter- depth compared to bare soil], because they reflect Additional colors that are being investigated native to conventional plastic mulches with their back into the plant canopy most of the incoming currently are red, blue, yellow, gray, and orange, retrieval and disposal problems (Ennis, 1987). solar radiation (Ham et al., 1993). These mulches which have distinct optical characteristics and Although photodegradable plastic looks very much can be used to establish a crop when soil tempera- thus reflect different radiation patterns into the like other plastic mulches when it is installed, it tures are high and any reduction in soil tempera- canopy of a crop, thereby affecting plant growth can be broken down by ultraviolet sunlight. The tures is beneficial. Depending on the degree of and development (Decoteau et al., 1989; Orzolek actual rate of breakdown depends on several fac- opacity of a white mulch, it may require the use of and Murphy, 1993). This light reflectivity can tors, including temperature, the proportion of the

HortTechnology ● July/Sept. 1996 6(3) 151 Vegetable Production Using Plasticulture

plastic shaded by the crop, and the amount of or triple-crop by fertilizing succeeding crops require only a screen or disc filter to remove sunlight received during the growing season. When through the drip irrigation tape or tubing using a particles. It is very important to determine if pre- using photodegradable plastic mulch, keep in fertilizer proportioner. This allows greater produc- cipitates or other contaminants in the water could mind that decomposition of the buried edges (com- tion for the investment in plastic mulch and drip cause a plugging problem. A water analysis is monly referred to as the tuck) is initiated by lifting irrigation equipment. The major components of a essential before installing a drip system. Munici- them out of the soil and exposing them to sunlight. drip irrigation are 1) drip tubes or drip tapes; 2) pal sources generally provide documentation of Research is being conducted currently on a filters—media, screen or disc; 3) pressure regula- water quality tests, making it easier to spot poten- photodegradable mulch overlay system, in which tors—spring or valve; 4) valves—hand-operated, tial problems. the top layer of black photodegradable mulch hydraulic, or electric; 5) controllers—simple time Surface water such as streams, ponds, pits, degrades and increases the exposure of a white clocks to complex computer controlled units that or rivers contain bacteria, algae, or other aquatic nondegradable layer (Graham et al., 1995). This run many zones; 6) injectors—for introducing life. Consequently, the use of agricultural sand particular change would lower the soil temperature chemicals and fertilizers into the irrigation system. media filters with surface water is an absolute later in the growing season. The potential use for Because vegetables are planted in rows, a necessity. These filters are generally more expen- this would be in a double-cropping system, where drip tube or tape is used to wet a continuous strip sive than screen or disc filters. Assistance from an the same mulch is used for spring and fall crops ( along the row. The drip tape is generally 8 mil (.20 irrigation dealer or professional familiar with drip such as bell peppers planted in the spring followed mm) thick and usually is used for 1 year and then irrigation system design and installation is recom- by squash in late summer). The concept could be discarded, whereas drip tube is heavier, 25 mil mended strongly and can be very helpful in avoid- pursued further with several color changes during (0.64 mm) thick and retrieved and used again. The ing problems later. Other major considerations are the season. The color changes would be accom- outlet holes can be spaced from 8 to 24 inches (20 crop water management and maintenance of the plished by having more than one coextruded layer to 61 cm) apart; 12 inches (30.4 cm) is a common drip irrigation system. of differently pigmented photodegradable plastic spacing for vegetable crops. Companies like Rob- on top of the nondegradable mulch. erts Irrigation Products, San Marcos, Calif.; T- Fertigation Systems International, San Diego, Calif.; Chapin Drip irrigation Watermatics, Watertown, N.Y.; and Hardie Irriga- Once a drip irrigation system has been in- tion, Laguna Calif.; manufacture drip tapes, and stalled, it makes economic and environmental Drip irrigation is another cornerstone in a Netafim, Altamonte Springs, Fla., is a major manu- sense to fertilize the crop via the drip system as plasticulture production system. It should be used facturer of drip tubing. needed. If done properly, this results in more with plastic mulch to obtain the greatest benefit. The source of the water supply for drip efficient use of fertilizers and probably lessens Water savings with drip irrigation can amount to as irrigation is extremely important and can include fertilizer contamination of groundwater through much as 80% compared to other irrigation meth- wells, ponds, lakes, municipal lines, or pits. Well- leaching below the plant root zone (Hochmuth, ods (Bogle and Hartz, 1986). You also can double- water sources generally are fairly clean and may 1992).

Table 2. Plant spacing for plasticulture.

In-row spacing Between-row spacing [inches (cm)] on plastic beds

Crop Single row Double row [inches (cm)] Common on plastic Cucumber (slicers) 12–18 (30.5–45.7) 9–18 (22.8–60.9) 12–14 (30.5–35.6) Cucumber (pickles) 12–18 (30.5–45.7) 9–18 (22.8–60.9) 12–14 (30.5–35.6) Eggplant 18–24(45.7–60.9) 18–30 (45.7–76.2) 14–16 (35.6–40.6) Honeydew 18–24 (45.7–60.9) ------Lettuce (leaf) --- 6–9 (15.2–22.8) 9–12 (3 rows) (22.8–30.5) Muskmelon 18–24 (45.7–60.9) ------Okra 12–18 (30.5–45.7) 18 (45.7) 14–16 (35.6–40.6) Pepper 12–16 (30.5–40.6) 12–16 (30.5–40.6) 12–14 (30.5–35.6) Pumpkin 24–48 (60.9–122) ------Squash Summer 12–18 (30.5–45.7) 16–24 (40.6–60.9) 14–16 (35.6–40.6) Winter 18–48 (45.7–122) ------Tomato 18–24 (45.7–60.9) ------Watermelon 24–48 (30.5–122) ------Less common on plasticz Broccoli --- 8–12 (20.3–30.5) 9–12 (22.8–30.5) Cabbage --- 9–12 (22.8–30.5) 12–16 (30.5–40.6) Cauliflower 18 (45.7) 18–24 (45.7–60.9) 14–18 (35.6–45.7) Chinese cabbage 12 (30.5) 9–12 (22.8–30.5) 12–14 (30.5–35.6) Collard 9–12 (22.8-30.5) 12–18 (30.5–45.7) 12–18 (30.5–45.7) Sweet corn 6 (15.2) 6–12 (15.2–30.5) 12–18 (30.5–45.7) Greens --- 6–12 (15.2–30.5) 9–12 (2–3 rows) (22.8–30.5) Onion --- 4–6 (10–15.2) 4–10 (3–6 rows) (10–25) z Used in double- or triple-cropping.

152 HortTechnology ● July/Sept. 1996 6(3) In its broadest sense, fertigation is feeding a mulch and drip irrigation. Once wind protection is support and required venting during the day (Hall crop by injecting soluble fertilizers into water in the no longer required, the grain strips are mowed and and Besemer, 1972). irrigation system.A variety of injectors [vacuum used as drive rows for spraying for insect and To eliminate the need for manual venting, a (venturi type) pumps—small electric powered or disease control and for harvesting. variety of materials has been developed: slitted those powered by the irrigation water] are available polyethylene covers that require wire hoops; Agryl to perform this operation. If fertigation is to be Stand establishment technology P17 (Sodoca Mfg., France), a floating, nonwoven successful, irrigation scheduling must be coordi- sheet; Gromax (Gromax Plasticulture Ltd., nated closely with nutrient needs of the crop (Clark Crop establishment in a plasticulture system Pensacola, Fla.), a white, point-bonded, polypro- et al., 1991). To be a good fertigator, a grower first involves either transplanting or direct seeding. pylene material; Reemay (Ken-Bar, Reading, needs to be a good irrigator. Well grown, containerized vegetable transplants Mass.), a spunbonded fabric; Typar T- are integral parts of this production system. Infor- 518 (Ken-Bar, Reading, Mass.), 1.25 oz/sq.yd. Strip fumigation and soil solarization mation on the production of high-quality veg- ; and Vispore(Tredegar Industries, etable transplants is readily available from any Richmond, Va.), a polyethylene sheet with tiny In many production areas, especially the state extension service. For extra earliness of pep- pores (Wells and Loy, 1985). Another use of southeastern United States and California, sanitiz- per and tomato crops, containers with large cell rowcovers is as physical barriers that exclude ing the soil is a requirement. Plastic mulches are sizes of 3 to 4 inches (9.6 to 10 cm) are recom- insect pests and protect the crop in the early stages used with chemical fumigants or as covers during mended. For other vegetable crops, a cell size of growth, (Natwick and Durazo, 1985). soil solarization. In row or strip application of a between 1 to 2 inches (2.5 to 5 cm) is a good High tunnels or minimally heated protective fumigant, the amount of material actually applied general recommendation. Transplants can be set structures are another option in a plasticulture on an acre will depend on row width and will be a by hand or machine, with single or multirow units, system. They can be used to extend the spring and percentage of the broadcast rate. The temperature e.g., Kennco’s water-wheel plantsetter (Kennco fall growing season. High tunnels are covered with of the soil should be at least 50 °F (10 °C), and soil Mfg. Inc., Ruskin, Fla.); mechanical mulch planter a single layer of polyethylene film (Wells, 1991). should be well worked and free from undecomposed (Mechanical Transplanter Co., Holland, Mich.); or plant debris and have adequate moisture for seed water-wheel (Rain-Flo Irrigation, East Earl, Pa.), Pest management germination. If the weather and soil are warm, the with excellent results. The following vegetables fumigant should escape through the plastic mulch have been transplanted successfully: tomato, pep- Another component of the plasticulture sys- in 12 to 14 days. Fumigation is used primarily for per, eggplant, watermelon, muskmelon, honey- tem is a good integrated program for insect, dis- nematode control, but, by using a multipurpose dew, summer squash, cucumber, onion, and okra. ease, and weed control. To obtain good insect and fumigant (e.g., Terr-O-Gass 67 or 98-2, Great In specialty or niche marketing situations, other disease control, it is important to use a sprayer that Lakes Chemical Corp., West Lafayette, Ind.), it can crops such as sweet corn, herbs, leaf lettuce, and generates sufficient pressure to provide good spray provide good control of soil-borne diseases as cole crops can be transplanted. Mechanical seed- penetration and coverage. This means using spray- well (Scoville and Leaman, 1965). Soil solariza- ers are available in single or multirow models that ers with pumps capable of generating 200 to 400 tion is another way to control soil pests. Solariza- will plant directly through the plastic mulch, such psi (14 to 28 kg cm-2) with appropriately sized tion describes a hydrothermal method of soil as the polyplanter (Ferris Farms, New Wilmington, nozzles. It is important to use chemical sprays deinfestation that occurs in moist soil covered by Pa.) and the Stanhay/Stephens 4100 (Triangle M when needed in as efficient a manner as possible mulch film (mainly clear) and exposed to sunlight Equipment Ltd., Morocco, Ind.). This equipment is to control the targeted pest or problem without during the hot summer months (Stapleton, 1991). good for direct-seeded crops of sweet corn and damaging the environment. As in nonplasticulture cucumbers as well as other crops. Some spacing growing systems, the use of an integrated pest Windbreaks recommendations are shown in Table 2. management approach that combines use of dis- ease-resistant varieties, chemical and biological The use of windbreaks, permanent (trees) Season-extending technology control practices, crop rotation, etc., is recom- and annual (small grain), is an important part of the mended. Only approved should be used entire plasticulture system, but often it is over- Rowcovers can increase earliness by creat- between rows of mulched plastic beds, because looked. Windbreaks consisting of strips of winter ing a minigreenhouse effect. The first rowcovers this is not considered a fallow area. The use of low- wheat, rye, or barley should be established to used were solid polyethylene sheeting that needed pressure sprayers coupled with shielded applica- protect young vegetable seedlings from prevailing winds. A combination of permanent and annual Table 3. Suggested spring–fall crop sequences. windbreaks can modify wind profiles and influ- ence temperatures and other microclimate fea- Spring Fall tures (Hodges et al., 1994). Also, windbreaks can Pepper Summer squash, cucumber, cole crops serve as habitat for beneficial and pest insects (Dix Tomato Cucumber, summer squash, cole crops and Leatherman, 1988). Summer squash Pumpkin, tomato, cole crops For maximum effectiveness, the grain strips Eggplant Summer squash should be planted in the fall. Each grain strip Cucumber Tomato, pumpkin, summer squash should be the width of a small-grain drill [10 to 12 Muskmelon Tomato feet (3 to 3.6 m)], with strips far enough apart to Watermelon Tomato accommodate five or six mulched beds on 5- to 6- Honeydew Tomato foot (1.5 to 1.8-m) centers. Topdressing the strips Cole crops Summer squash, pumpkin, muskmelon, tomato in the spring helps to ensure a dense stand. Lettuce Summer squash, pumpkin, muskmelon, tomato Another option is to plant a solid grain cover Snap bean Summer squash, pumpkin, muskmelon, tomato crop in the fall. It is important to till the crop area Sweet corn Summer squash, tomato, okra, cucumber early enough in spring so that cover crop debris Tomato, summer squash, cucumber, muskmelon, pumpkin, okra will not interfere with application of the plastic

HortTechnology ● July/Sept. 1996 6(3) 153 Vegetable Production Using Plasticulture

Table 4. Yields of selected vegetables using plasticulture. Graham, H.A., D.R. Decoteau, and D.E. Linvill. 1995. Development of a polyethylene mulch system that changes Crop Yields/A (ha) color in the field. HortScience 30:265–269. Eastern muskmelon 8000–9000 fruit at 4–6 lb/fruit (20,320–22,230 fruit at 1.8–2.7 kg) Hall, B.J. and S.T. Besemer. 1972. Agricultural Western muskmelon 12,000–15,000 fruit at 3–4 lb/fruit (29,640–37,050 fruit at 1.4–1.8 kg) in California. HortScience 7:373–378. Cucumber 1200 bu (55 lb/bu) (2964 bu (24.9 kg/bu) Ham, J.M., G.J. Kluitenberg, and W.J. Lamont. 1993. Pepper 1600 bu (25 lb/bu) (3952 bu (11.3 kg/bu) Optical properties of plastic mulches affect the field Squash 800 bu (45 lb/bu) (1976 bu (20.4 kg/bu) temperature regime. J. Amer. Soc. Hort. Sci. 118(2):188– Tomato 3200 boxes (20 lb/box) (7904 boxes (9.1 kg/box) 193. Watermelon 3000 fruit (7410 fruit) Ham, J.M and G.J. Kluitenberg. 1994. Modeling the effect of mulch optical properties and mulch-soil contact resistance on soil heating under plastic mulch culture. Agr. For. Meteorol. 71:403–424. tion of herbicides is recommended. This ap- earliness and increases in total yield could present proach will prevent applying the herbicide mate- a marketing problem if not properly anticipated. Hochmuth, G.J. 1992. Fertilizer management for drip irrigated vegetable in Florida. HortTechnology 2:27–32. rial on the plastic bed, resulting in potential crop Also, when a crop is grown using plasticulture, it injury from increased concentration of herbi- can be used as a marketing tool. For example, Hodges, L., M.E. Dix, J. Brandle, R. Wright, and M. cides in the planting hole. muskmelons grown in Texas are marketed in ad- Harrell. 1994. Effects of shelterbelts on insect pests in Reflective plastic mulches, like silver-faced vertisements and on individual melon boxes: muskmelon. Proc. Nebraska Fruit and Veg. Growers Conf. p. 19–28. plastic mulch, have been shown to interfere with “These melons grown using plastic mulch and the movement of aphids, which often vector drip irrigation.” Producers feel this advertisement Lamont, W.J., K.A. Sorensen, and C.W. Averre. 1990. virus diseases to various vegetable crops [e.g., promotes product quality and environmental aware- Painting aluminum strips on black plastic mulch reduces watermelon mosaic virus II, which causes green ness to buyers and the buying public. mosaic symptoms on summer squash. HortScience 25:1305. streaks in summer squash (Lamont et al., 1990) and mottling and green streaks in yellow squash, Summary Lamont, W.J. and E.B. Poling. 1986. A fresh way of melons, and pumpkins]. looking for profits: double-cropping , musk- Plasticulture is a production system that melons. Fruit South 7(4):8–11. Cropping strategies—Double- or involves high input costs and levels of manage- Liakatas, A., J.A. Clark, J.L. and Monteith. 1986. Mea- triple-cropping ment and is subject to mismanagement and risk, surements of the heat balance under plastic mulches. just as any production system. With proper plan- Part I. Radiation balance and soil heat flux. Agr. For. Double- or triple-cropping in regions where ning, attention to details, and dedication to all Meteorol. 36:227–239. this is possible is another important component aspects of the plasticulture system, the opportu- Loy , B., J. Lindstrom, S. Gordon, D. Rudd, and O. Wells. of the plasticulture system. With such a strategy, nity exists to reduce the acreage of an existing 1989. Theory and development of wavelength selective one can grow the equivalent of 2 or 3 acres (0.8 operation and possibly increase profits using effi- mulches. Proc. 21st Natl. Agr. Plastics Congr. p. 193– to 1.2 ha) of produce on 1 acre (0.40 ha) of land cient production techniques. Some yields of vari- 197. using the plasticulture system inputs (plastic ous vegetable crops using plasticulture are pre- Marr, C.W. and W.J. Lamont. 1992. Profits, profits, mulch, drip tape) already in place. sented in Table 4. profits - three good reasons to try triple cropping. Amer. One interesting cropping scheme that has Veg. Grower 40:18, 20. been investigated in Kansas is broccoli or cab- Natwick, E.T. and A. Durazo, III. 1985. Polyester covers bage followed by yellow summer squash, which Literature Cited protect vegetables from whiteflies and virus disease. is then followed by broccoli, cabbage, or Chi- Calif. Agr. 39(7+8):21–22. nese cabbage (Marr and Lamont, 1992). Bogle, O. And T.K. Hartz. 1986. Comparison of drip and Orzolek, M.D. and J.H. Murphy. 1993. The effect of Another cropping scheme is annual hill furrow irrigation for muskmelon production. HortScience colored polyethylene mulch on the yield of squash and strawberries followed by muskmelons (Lamont 21:242–244. pepper. Proc. 24th Natl. Agr. Plastics Congr. p. 157– and Poling, 1986). Also, in the event that the first 161. crop is a failure, double- or triple-cropping is a Clark, G.A., C.D. Stanley, D.N. Maynard, G.J. Hochmuth, E.A. Hanlon, and D.Z. Haman. 1991. Water and fertilizer Schales, F.D. and R. Sheldrake. 1963. Mulch effects on potential means of recouping investments in such management and microirrigated fresh market tomatoes. soil conditions and tomato plant response. Proc. 4th inputs as plastic mulch, drip tape or tubing, and Trans. Amer. Soc. Agr. Eng. 34:429–435. Natl. Agr. Plastics Conf. p. 78–90. fertilizer. Fertigating through the drip system makes it relatively easy to supply sufficient nutrients to a Decoteau, D.R., M.J. Kasperbauer, and P.G. Hunt. 1989. Scoville, R.H. and D. Leaman. 1965. Polyethylene uses Mulch surface color affects yield of fresh-market toma- in soil fumigation. Proc. 6th Natl. Agr. Plastics Conf. p. second or third crop. Some suggested spring–fall toes. J. Amer. Soc. Hort. Sci. 114:216–219. 98–99. sequences are shown in Table 3. Dix, M.E. and D. Leatherman. 1988. Insect management Stapleton, J.J. 1991. Use of soil solarization for the in windbreaks, p. 501–512. In: J.R. Brandle, D.L. Hintz, control of soil pests. Proc. 23rd Natl. Agr. Plastics Marketing and J.W. Sturrock (eds.). Windbreak technology: Pro- Congr. p. 266–271. ceedings of an international symposium on windbreak The opportunity to produce much higher technology. Elsevier, New York. Tanner, C.B. 1974. Microclimate modification: Basic overall yields beginning earlier in the season concepts. HortScience 9:555–560. using plasticulture requires producers to have Emmert, E.M. 1957. Black polyethylene for mulching vegetables. Proc. Amer. Soc. Hort. Sci. 69:464–469. Wells, O.S. and J.B. Loy. 1985. Intensive vegetable their marketing strategies and outlets as refined production with rowcovers. HortScience 20:822–826. as possible before planting any crop. It is impor- Ennis, R.S. 1987. PlastigoneTM a new, time-controlled tant for producers to realize that, if they planteed photodegradable, plastic mulch film. Proc. 20th Natl. Wells, O.S. 1991. High tunnels shelter early crops. Amer. 50 acres (20.2 ha) of tomatoes on bare ground Agr. Plastics Congr. p. 83–90. Veg. Grower 39(2):44, 46–47. before switching to plasticulture, the potential

154 HortTechnology ● July/Sept. 1996 6(3)