a self-study course from MSU Extension Continuing Education Series Management 10 Module No. 10 CCA 2.5 NM Commercial CEU and Amendments by Ann McCauley, Soil Scientist; Clain Jones, Extension Specialist; and Jeff Jacobsen, College of Dean

Introduction This module is the tenth in a series of Extension materials designed to provide Extension agents, Certified Crop Advisers (CCAs), consultants, and producers with pertinent information on nutrient management issues. To make the learning ‘active’, and to provide credits to CCAs, a quiz accompanies this module. In addition, realizing that there are many other good information sources, including previously developed extension materials, books, web sites, and professionals in the field, we have provided a list of additional resources and contacts for those wanting more in-depth information about fertilizers and amendments. This module covers the Rocky Mountain CCA Nutrient Management Competency Area VI: Nutrient sources and applications. Objectives After completing this module, the reader should: 1. Understand grade and calculate elemental nutrient content of a fertilizer 2. Recognize fertilizer manufacturing processes and forms 3. Know the effects of various fertilizers on soil pH and salt concentrations 4. Understand fertilizer reactions in the soil 5. Determine the appropriate soil amendment for a given soil condition 6. Recognize the potential for heavy metal accumulation following fertilizer or amendment application and calculate maximum allowable metal levels for products 4449-10 May 2009 Background Commercial fertilizer and amendment 15-30-15 use increased substantially worldwide GUARANTEED ANALYSIS during the latter half of the 20th century st and continues to increase into the 21 Total (N)...... 15.0% century. As a result, numerous products 5.8% Ammoniacal Nitrogen have emerged, offering a variety of 9.2% Nitrogen nutrient contents, physical forms, and Available Phosphoric Acid (P2O5).....30.0%

other properties to meet individual Soluble Potash (K2O)...... 15.0% needs. A number of these materials and Boron (B)...... 0.02% their applications have been described in Copper (Cu)...... 0.07% Nutrient Management Modules 2-7. 0.07 Soluble Copper (Cu) In choosing a fertilizer or amendment Iron (Fe)...... 0.15% product, a buyer should appraise the 0.15% Chelated Iron following: Manganese (Mn)...... 0.5% 1) content ( and other 0.05% Chelated Manganese components); Molybdenum (Mo)...... 0.0005% Zinc (Zn)...... 0.06% 2) cost per unit of available nutrient or 0.06 Water Soluble Zinc amendment; 3) ease of handling and application costs; Derived from Urea, Ammonium Phosphate, Urea Phosphate, Muriate of Potash, Boric 4) reaction effects in the soil; and Acid, Copper Sulfate, Iron EDTA, Manganese 5) personal preference. EDTA, Sodium Molybdate, and Zinc Sulfate. The purpose of this Figure 1. Sample fertilizer label. module is to explain # terminology, physical manufacturers are required to state the Q&A 1 and chemical properties, grade on each product label. Fertilizer and soil reactions grade is generally labeled as a three- associated with common number code (Figure 1) of the three Why are P and K commercial fertilizers primary macronutrients: nitrogen (N), labeled in their oxide and amendments. (P), and (K). The mention (or The first value corresponds to total forms? non-mention) of nitrogen content, the second to available

any products in this phosphorus (P2O5), and the third to water P2O5 and K2O are remnants publication does not soluble potash (K2O) content. Each value from the days when geochemists indicate endorsement or represents a percentage of nutrient content reported the contents of lack of endorsement of by weight. For example, in Figure 1, 15% minerals in terms of the oxides any particular product. of the fertilizer is N, 30% is P O , and 15% formed upon heating. When laws 2 5 is K2O. Thus, a 50 pound bag of 15-30-15 governing the sale of fertilizers Fertilizer contains 7.5 pounds of N, 15 pounds of required the labeling of fertilizer P2O5, and 7.5 pounds of K2O. grade, these oxide forms made Materials Total N content is represented as it onto the label. While most elemental N and may be further broken Co n t e n t fertilizer producers still report down into four N forms: nitrate nitrogen, The amount of P and K in their oxide forms, ammoniacal nitrogen, water soluble nutrient present in a there is some progress being organic nitrogen (and/or urea), and water fertilizer material is made toward stating the simple insoluble nitrogen. Knowing which N form the fertilizer grade, or elemental forms (adapted from is present in a fertilizer is important in guaranteed analysis. Brady and Weil, 1999). determining the availability of N in the soil By law, fertilizer (see Nutrient Management Module 3).

2 Module 10: Commercial Fertilizers and Soil Amendments P and K are labeled as their oxide forms, P O and K O, respectively, rather 2 5 2 Table 1. Conversion between %P O , %K O than their elemental forms (Q & A 2 5 ­2 #1). Therefore, conversion factors are and %P, %K required to calculate elemental P and K concentrations in a given fertilizer (Table Multiply by Multiply by Column A Column B 1, Calculation Box #1) and are derived A to get B B to get A from the proportion of P in P2O5 and K in K2O. % P O % P 0.44 2.3 In addition to primary macronutrients, 2 5 fertilizers may contain other nutrients, % K2O % K 0.83 1.2 such as sulfur (S), iron (Fe), boron (B), zinc (Zn), and molybdenum (Mo). These nutrients may be added range is the result of fertilizers containing as additional nutrients or may be other constituents (impurities), moisture, constituents (impurities) remaining in or filler materials (inert compounds) the fertilizer material following mining that cause nutrient content by weight to and manufacturing processes (discussed change. So, although many fertilizers are later). If present as additional nutrients often referred to by their typical grade (as in Figure 1), nutrients will be listed (i.e., all MAP fertilizers are often called 11- on the fertilizer label on an elemental 52-0), a particular fertilizer product may basis, similar to N. Forms and solubilities in fact have a different grade depending on may also be listed. If a significant source the fertilizer source and manufacturing of a particular nutrient, other than N, process. P, or K, is present in the fertilizer, it is Based on their primary nutrient content (N, P O , K O), fertilizers are typically labeled as a fourth value in the 2 5 2 fertilizer grade. This is most often seen referred to as being single-nutrient with fertilizers containing S (e.g., 21-0-0- or multiple-nutrient. Single-nutrient 24(S)). fertilizers, such as urea (46-0-0), contain Table 2, next page, lists typical only one primary macronutrient and are compositions for common fertilizers. Note also called ‘simple’ or ‘straight’ fertilizers. that some of the fertilizer sources have a In contrast, multiple nutrient fertilizers range of nutrient contents; for instance, contain more than one nutrient, such monoammonium phosphate (MAP) can as (DAP, 18-46- 0), and may be referred to as ‘mixed’ or contain between 48% and 62% P2O5. This

Calculation Box #1

Calculation: Amount of available P in a fertilizer = % P2O5 x 0.44

Amount of soluble K in a fertilizer = % K2O x 0.83

Example: How much N, P, and K are in a 25 pound (lb) bag of 16-6-12?

Recall that the numbers given in the fertilizer grade are a percentage of that nutrient in the fertilizer by weight and can be expressed as a fraction (i.e., 6% = 0.06).

Since a conversion factor is not required for N, N content = 0.16 x 25 lb = 4 lb of N

The conversion factor for P2O5 is 0.44, so P content = 0.06 x 0.44 x 25 lb = 0.66 lb of P

The conversion factor for K2O is 0.83, so K content = 0.12 x 0.83 x 25 lb = 2.5 lb of K

Module 10: Commercial Fertilizers and Soil Amendments 3 ‘complex’ fertilizers. A fertilizer or blend analysis fertilizers. This is due to less containing all three primary nutrients ‘other’ material in high analysis fertilizers, (e.g., 15-30-15) is a ‘complete’ fertilizer. resulting in reduced transportation, Fertilizers with relatively large storage, and application costs. amounts of nutrient(s) per unit weight Additional Fertilizer Information are ‘high analysis’ fertilizers. For instance, Fertilizer labels, material safety data urea (46-0-0) supplies more N per pound sheets (MSDS), and product specification of fertilizer than (34-0- sheets also supply additional information 0). Thus, urea has a higher analysis for N regarding physical and chemical than ammonium nitrate. Generally, high characteristics of the product. MSDS and analysis fertilizers are more expensive product specification sheets are available per ton than low analysis fertilizers, but from the fertilizer manufacturer and/or may provide nutrients at a lower cost distributor. per unit of available nutrient than low

Table 2. Typical nutrient compositions of common fertilizers (Modified from Havlin et al., 1999).

Frequently Molecular Fertilizer Source Used % N % P O % K O % S Physical State Form 2 5 2 Abbreviations Anhydrous AA NH 82.0 — — — Gas 3 Ammonium AN NH (NO ) 34 — — — Solid (pellets) nitrate 4 3 Urea-ammonium UAN 28-32 — — — Liquid nitrate Monoammonium MAP NH H PO 11-13 48-62 1-3 Solid phosphate 4 2 4 Diammonium Solid DAP (NH ) HPO 18-21 46-54 — 2 phosphate 4 2 4 (granules) Ammonium NH H PO • phosphate- — 4 2 4 13-16 20-39 — 15 Solid (NH ) SO sulfate 4 2 4 Ammonium Solid — (NH ) SO 21 — — 24 sulfate 4 2 4 (granules) Potassium — KCl — — 60 — Solid chloride Potassium — K SO — — 52 18 Solid sulfate 2 4

Urea CO(NH2)2 46 — — — Solid (pellets) Triple super- TSP or CSP Ca(H PO ) — 44-53 — 1-1.5 Solid phosphate 2 4 2

4 Module 10: Commercial Fertilizers and Soil Amendments Solid fertilizer physical characteristics anhydrous ammonia include color, particle size, and bulk (AA) fertilizer, or for the density. Particle size is determined as manufacture of other N # the size and amount of product retained fertilizer products. AA Q&A 2 on a given ‘mesh size’ screen. Mesh size is the highest N analysis refers to the number of screen wires per fertilizer available and Why have N fertilizer inch; increasing mesh size corresponds provides N at the lowest prices fluctuated so to smaller screen openings. Depending cost per pound of actual on fertilizer type and manufacturer, there N. Urea is formed by much in recent years? may be a range of particle sizes for a given combining carbon Although atmospheric N fertilizer. Bulk density refers to the mass dioxide (CO2) with NH3 of dry fertilizer per unit of bulk volume, and is the highest solid supplies are abundant, the usually in pounds per cubic foot. Bulk fertilizer source of N. energy required to industrially density may be labeled as loose or packed As its name implies, fix N is more limited. Natural particles (or both). Particle size and ammonium nitrate is gas is the main source of bulk density information are important equal parts ammonium energy used to synthetically + - fix N, with more than 70% of properties for determining fertilizer (NH4 ) and nitrate (NO3 ) reaction time in the soil and for blending and provides both forms ammonia production costs being and application purposes (discussed later). of plant-available N. consumed by natural gas prices Typical chemical fertilizer properties (Phillips and Mathers, 2001). In Phosphorus listed include molecular weight, pH, and recent years, natural gas costs Unlike N fertilizers, moisture content. Molecular weight is have increased considerably, in most material for P the atomic weight of all elements in the turn causing N fertilizer costs fertilizers comes from fertilizer molecule or ‘carrier.’ A fertilizer to rise as well. As N fertilizer mined rock phosphate carrier is the molecular form containing use and consumption of non- (RP). RP is mined the plant nutrient. For example, potassium renewable natural gas supplies from raw ore deposits chloride (KCl) is a carrier of K and its increase, either U.S. fertilizer in various areas of molecular weight is the atomic weight of K manufacturers are going to the world, including (39) plus the atomic weight of Cl (35.5), or curtail production or prices Florida, Idaho, Montana, 74.5 (atomic weights are from the periodic of N fertilizers will increase to North Carolina, and table of elements). Molecular weights recover manufacturing costs. Wyoming (Figure 2). can be used to calculate percent weight RP can be used directly content of all components in a fertilizer. as a fertilizer (21-47% P O ; considered Fertilizer pH is measured as the pH of 2 5 organic), or used to produce other P the material in a water solution and is an fertilizers through either heat- or acid- indication of a fertilizer’s initial reaction treatments. The in the soil upon being applied. Moisture treatment of RP content is typically less than 1% for most considerably solid fertilizers. increases P solubility and Or i g i n a n d Ma n u f a c t u r e o f Fe r t i l i z e r s effectiveness. Nitrogen Ammonium From the viewpoint of commercial phosphates agriculture, industrial N fixation is the (MAP and DAP) most important source of N as a plant are produced nutrient (Q&A #2). Through the Haber- by combining

Bosch process, hydrogen (H2) and N2 gases phosphoric acid react under intense pressure and heat to (a product of acid- form ammonia gas (NH3(g)) (Havlin et al., treating RP) and Figure 2. Phosphorus mine 1999). The produced NH can be used as + 3 ammonium (NH4 ) operation.

Module 10: Commercial Fertilizers and Soil Amendments 5 to provide a fertilizer source of both N and Micronutrients P. The main difference between MAP and Most micronutrients supplied in DAP is N content: MAP (monoammonium fertilizers are mined from raw ore or phosphate) has one ammonium molecule are by-products of industrial processes. for every one phosphate molecule and Forms of micronutrients include DAP (diammonium phosphate) has two oxides, carbonates, and metallic salts. ammonium molecules for every one Table 4 in Nutrient Management phosphate molecule. Implications of this Module 7, Micronutrients lists some difference will be discussed later. Triple common micronutrient fertilizers and superphospate (TSP) is an orthophosphate their chemical properties. Some metal synthesized by treating RP with sulfuric micronutrients are ‘chelated,’ meaning

acid (H2SO4) to provide a high P analysis a synthetic organic compound is hooked fertilizer. TSP is not as commercially to the metal to increase solubility (see available as it has been traditionally. NM 7 and NM 8). Chelating agents for various micronutrient metals include Potassium EDTA, HEEDTA, NTA, DTPA, and EDDHA. K fertilizers, referred to as potash, Chelated forms of micronutrients are are mined from K salt deposits found generally more expensive than non- beneath the earth’s surface, in the beds of chelated forms, but can be considerably dried lakes and seas, and from salt water more effective per unit of nutrient. reserves. The world’s largest potash deposit is located in Saskatchewan, Canada, and Fe r t i l i z e r Fo r m s mining also occurs in California, Israel, Fertilizer materials are available in New Mexico, and Utah. After removal, the either solid (dry) or liquid forms and are salts are purified and treated, yielding often blended to meet individual nutrient fertilizer compounds such as potassium needs. A common question concerning chloride (0-0-60) and potassium sulfate fertilizer forms is whether solid fertilizers (0-0-53-17). and liquid fertilizers differ agronomically. Secondary Nutrients Most solid and liquid fertilizers contain the Sulfur (S)-containing fertilizers same basic nutrients and a wide range of include ammonium sulfate (21-0-0- studies have concluded that when applied 24), elemental S0 (0-0-0-100), and under long-term conditions of equivalent dispersible, granular S0 (S0 + bentonite) nutrient rates and similar placement, (0-0-0-90). Other S sources are listed liquid and solid fertilizers are essentially in Nutrient Management Module 6, equal agronomically. However, because Secondary Macronutrients. Ammonium fertilizer effectiveness is dependent upon sulfate supplies both N and S and reacts nutrient solubility and availability relative fairly rapidly in the soil. In comparison, to their placement and timing, there are elemental S and bentonite-S supply S times when the effectiveness of the two more slowly to plants and effectiveness will forms can differ significantly (Wolf et al., depend on particle size, rate, method, and 1985). time of application. Solid Fertilizers Commercial Ca and Mg fertilizers Depending on nutrient content and are not commonly used in this region manufacturing processes, solid fertilizers due to high Ca and Mg concentrations may differ in size, shape, color, and bulk naturally occurring in many . Some density. Solid fertilizer forms are classified amendments contain sources of Ca and Mg by size and shape and include granules, and will be discussed. prills, pellets, and powder. Granular fertilizer particles range in size from approximately 1 to 4 mm in diameter and

6 Module 10: Commercial Fertilizers and Soil Amendments are roughly round in shape (Figure 3). of nutrients. Granular fertilizers are the most common Advantages of form of solid fertilizer used. Prills are blending fertilizers made by solidifying free-falling droplets are reduced in air to form nearly spherical particles. application costs Pellets are nutrients compressed into (less passes and uniform sizes and nutrient content, and machinery use) powder fertilizers contain fine particles and a more even (less than 2 mm diameter). In general, distribution of finer sized particles will react more quickly nutrients. Two types than larger particles due to increased of blended fertilizers surface area and contact with the soil. are homogeneous However, larger particles may be easier to and heterogeneous store, handle, transport, and apply. (bulk blends). In recent years, many manufacturers Homogenous have begun coating granular fertilizers, fertilizers are Figure 3. Granular MAP fertilizer. primarily N and P, with thin layers of ‘chemically’ substances such as clay, oils, or waxes blended to to decrease dust production and prevent produce uniform caking during packaging, transport, _ IMC-Agrico J.R. Simplot storage, blending, and spreading. The use 100 of coated fertilizer has been questioned for Broadcast Broadcast _ its potential effect on nutrient availability, 80 Uncoated uptake, and yield. A recent study (Jones Coated _ and Jacobsen, 2005) found that dust 60 control coatings on MAP fertilizers from two manufacturers did not significantly 40 _ decrease Olsen P soil concentrations, P uptake by corn (Figure 4), or biomass 20 _ in either a low or high soil pH. In a few treatments, the coated fertilizers actually 0 _ resulted in higher P availability, uptake, and growth than the uncoated fertilizers. Incorporated Incorporated 80 _ Conclusions from this study suggest that P can readily diffuse through the fertilizer uptake (mg/plant) 60 _

coatings and, therefore, coatings are not P negatively altering fertilizer nutrient 40 _ availability and yield. ** Some solid fertilizers may be coated _ with a polymer to provide a controlled- 20 release of nutrients and greater nutrient _ efficiency. These specialty fertilizers may 0 Low High not be cost effective for many agricultural Low High systems, but are suitable for horticultural applications or high value cropping pH systems. Figure 4. Effects of coatings on P uptake in corn Blended Fertilizers from two MAP fertilizer manufacturers. Initial Olsen Both single and multiple nutrient P =10 ppm and 12 ppm for low and high pH soils, fertilizers can be blended to obtain respectively (Jones and Jacobsen, 2005). a desirable fertilizer grade or ratio ** - significant at P< 0.05

Module 10: Commercial Fertilizers and Soil Amendments 7 fertilizer particles of the same nutrient held in suspension with a suspending content, color, and size. Heterogeneous agent, usually a swelling-type clay. To fertilizers, on the other hand, contain avoid settling, suspension fertilizers should one or more fertilizer materials that are be applied soon after blending (within a ‘physically’ mixed. This generally results day or two) and some agitation may be in components or raw materials being required to homogenize the suspension of various colors and sometimes sizes. before application. Some and Heterogeneous fertilizers are often ‘custom insecticides may also be mixed with liquid blended’ for individual buyers based on soil fertilizers. test reports. Advantages of liquid fertilizers are that A potential problem concerning they can be diluted or concentrated for heterogeneous fertilizers is the segregation precise, even application and are easily of varying fertilizer components due handled by pumps and machinery. Liquid to different particle sizes and densities. fertilizers are commonly applied through Potash granules, for instance, have a water (), knifed-in, greater bulk density than urea granules broadcast, or banded (NM 11). Unlike solid and, with jarring or movement during fertilizers, liquid fertilizers are applied on a transport, the potash granules will settle volume rather than a weight basis and the below the urea granules. Segregation liquid density (pounds nutrient per unit of fertilizer components can cause volume) is needed to calculate application an uneven distribution of nutrients rates. This information should be on the to a field, resulting in possible yield product label. losses and nutrient deficiencies or even Liquid fertilizers generally have a lower toxicities. Segregation can be reduced nutrient analysis than solid fertilizers due by using materials of similar particle to the solubility limitations of nutrients in sizes and thoroughly mixing the blended a solution. Solutions can contain relatively fertilizer in the field prior to application. high analyses of N and P, yet have low Micronutrients and some solid pre-plant potash content because no more than 13% herbicides and insecticides can be added to potash will go into solution. Therefore, blends through impregnation on the solid most liquid fertilizers containing high granule. However, a granular form with a analysis of potash are suspension fertilizers size range similar to other components is because the potash remains dispersed in often preferred. the liquid rather than going into solution Not all fertilizer materials can be (CHPA, 2002). blended. For instance, S-bentonite should Critical factors to consider when not be blended with nitrate-N containing using liquid fertilizers are climate and fertilizers and the blending of solid urea storage. Most liquid fertilizers will ‘salt- and solid ammonium nitrate results in a out’ (precipitate out of solution into solid slushy-like mixture (Havlin et al., 1999). form) when temperatures become too cold. Before blending, the compatibility of all Salting-out temperatures will vary between ingredients should be assessed. fertilizer types and depend on content and nutrient analysis. The salting-out Liquid Forms temperature for a given fertilizer should be Liquid fertilizers are fluids in which stated on the product label or be available nutrients are dissolved in a water from the manufacturer. High analysis medium and include both solutions and liquid fertilizers generally have higher suspensions. Solutions contain completely salting-out temperatures; for instance, dissolved nutrients without solids, whereas a typical UAN solution of 32-0-0 has a suspensions contain some dissolved salting out temperature of 32oF, while the nutrients and some undissolved solid salting out temperature for a UAN solution nutrients. The undissolved nutrients are of 28-0-0 is 15oF (Overdahl et al., 1991).

8 Module 10: Commercial Fertilizers and Soil Amendments Furthermore, freezing temperatures can may have long-term effects on soil pH cause problems with storage containers following years of application and may be (expansion and cracking). Liquid fertilizers beneficial in alkaline soils. For Montana should be stored in appropriate storage and Wyoming soils, the magnitude of materials to prevent corrosion and acid-forming material reactions on pH are destruction of the storage compartments. believed to be countered by the relatively Aluminum alloys, stainless steel, and other high buffering capacity of most soils in non-corrosive materials are recommended the region and possibly cropping practices for the storage of liquid fertilizers (CHPA, (Jones et al., 2002; NM 8). However, 2002). isolated cases of lowered pH may occur; therefore, the effect of N fertilizers on pH Fertilizer Reactions in the Soil should be considered on acidic soils.

Alternatively, NH3-based fertilizers Ef f e c t s o n So i l pH (urea, AA, and UAN) can cause soil pH Soil pH can be affected by certain to temporarily increase (become more fertilizer applications. Generally, soil pH alkaline) as a result of H+ being taken is optimum between pH 6.5 and 7.5 (NM + out of solution to form NH4 (Figure 5B). 8). Some fertilizers may change long- This reaction occurs relatively quickly (on term soil pH after years of application, the order of hours to days). Volatilization whereas others have a more short-term of NH3 is a potential concern associated and ‘microsite’ effect. In this context, with a rise in pH following the application microsite refers to the area directly of NH3 fertilizers, particularly surface surrounding the fertilizer material and applied urea. Increases in pH promote extends approximately 1 inch from the site the formation of NH3 in the soil, thus of placement. leading to greater NH3 volatilization at N fertilizers can have varying effects high pH levels (Figure 6). Numerous on soil pH. Nitrification (the conversion studies have shown the loss of N from + - + of NH4 to NO3 ) and hydrolysis of NH4 - volatilization to be greatest under high based fertilizers can decrease (acidify) soil rates of urea applied at the soil surface, pH due to the release of H+ ions to the and to be substantially reduced with the soil solution (Figure 5A). This reaction incorporation of urea into the soil either

A + B NH4 Fertilizer Application NH3 Fertilizer Application

Nitrification + - + NH4 NO3 NH3 NH4 H+ Soil + Soil H+ Solution H + + + Solution H H+ H H H+

+ Figure 5 (A and B). Effects of NH4 (A) and NH3 (B) fertilizer applications on pH. Through nitrification, H+ ions are released to the soil, thereby decreasing pH (A). In contrast, + + the conversion of NH3 to NH4 ‘takes up’ H from the soil solution, thereby temporarily increasing soil pH.

Module 10: Commercial Fertilizers and Soil Amendments 9 20 up to 60% have been recorded in some calcareous soils from surface applied urea that was not immediately watered. In a 16 number of Montana field trials, broadcast application rates of up to 150 lb N/ac as 12 either urea or ammonium nitrate over fall, winter, and spring did not show any significant differences in yield or protein in 8

l o s , % f N a p i e d spring and winter wheat trials (Jackson and 3 Jacobsen, unpublished data). This suggests that N volatilization losses from urea 4

o t a l N H application are not significant in high pH T calcareous soils in Montana. 0 P fertilizers typically don’t have long- 4 4.5 5 5.5 6 6.5 7 8 term effects on soil pH, but short-term Soil pH microsite effects are evident between varying P fertilizers, including TSP (0-46- Figure 6. Effect of pH on NH3 volatilization (Fan and Mackenzie, 1993). 0), MAP (11-52-0), and DAP (18-46-0). TSP and MAP are acidic fertilizers that have pH values of approximately 1.0 and 3.5, mechanically or by rain or irrigation water respectively, whereas DAP is alkaline with a (Fenn and Miyomoto, 1981; Overrein and pH near 8.0. Microsite pH may temporarily Moe, 1967). In addition, studies suggest shift in response to a given P application, effects are greatest on soils with low thus possibly affecting the availability of buffering capacities and not as prevalent P and other nutrients near the fertilizer on well-buffered soils, although NH3 losses granule. A study conducted in the southern U.S. looked at interaction effects between P fertilizer pH changes and NH volatilization Table 3. Ammonia volatilization 3 when urea was applied with DAP, MAP, following constant rate of urea and TSP (Fan and Mackenzie, 1993). application with varying rates of TSP, Results found that when urea was surface applied at 440 lb/ac with MAP or TSP, NH3 MAP, and DAP. volatilization decreased as compared to (Modified from Fan and Mackenzie, 1993). urea alone, and increased when applied with DAP (Table 3). This suggests microsite pH changes attributed to P fertilizer sources can affect N loss via volatilization, Treatment* NH3 loss, % of urea N Site 1** Site 2*** and hence yield. Keep in mind, however, that soil pH change is also influenced by Urea Alone 4.7 9.8 other factors, including soil texture, pH, and buffering capacity, which may decrease Urea + TSP 1.8 4.9 microsite effects. For example, pH changes Urea + MAP 4.2 4.1 in well buffered soils are likely minimal Urea + DAP 12.8 14.2 compared to poorly buffered soils and microsite pH will not have as considerable *Constant rates of 0.5 g/kg of urea and 0.22 g/kg of P of an effect on nutrient reactions. material for each treatment. K fertilizers may have a slightly alkaline **Site 1 was a clay soil with a pre-treatment pH of 5.2. (higher pH) effect on soil because of the ***Site 2 was a silty clay loam with a pre-treatment pH addition of K+ cations to the soil solution. of 6.0. Most Montana and Wyoming soils are abundant in cations and the effect of K

10 Module 10: Commercial Fertilizers and Soil Amendments fertilizers on pH is negligible. Sa l t Ef f e c t The acidity of a fertilizer material is ‘Salt burn’ occurs when excessive measured as calcium carbonate equivalent concentrations of soluble salts come (CCE) and is a value often listed on the in contact with germinating seeds or fertilizer label. CCE is the number of roots and can result from a high rate pounds of calcium carbonate required of salt-forming fertilizers, improper to neutralize 100 pounds of a given fertilizer placement, irrigation with saline fertilizer. As equivalent acidity increases, water, or farming on saline (high salt fertilizer’s acidifying effect on the soil concentration) soils. Salts have a high increases, primarily due to acid produced attraction for water and can draw water as ammonium undergoes nitrification. out of seedling or root tissue, causing Table 4 shows some fertilizers and their plant injury and -like symptoms equivalent acidity in pounds calcium to occur, particularly on sandy soils. carbonate per 100 pounds of fertilizer. Of The potential for ‘’ (salt the fertilizers listed, anhydrous ammonia burn caused by fertilizer application) is and ammonium sulfate have the highest determined by the material’s salt index. potential to acidify soil per pound of Salt index is a measure of a fertilizer’s fertilizer. In summary, fertilizers can cause effect on the salt level in the soil solution soil pH to change, but these effects are and is calculated by placing the fertilizer only expected to be substantial on poorly material in soil and measuring the buffered sandy soils, which are rare in osmotic pressure (suction) of the soil Montana and Wyoming. solution. As the salt index increases, the

Table 4. Equivalent acidity or basicity, salt index, and solubility for selected fertilizers.1

Equivalent Solubility Fertilizer Material 2 Salt Index3 Acidity (lb material/ 100 gal water) (lb CaCO3) Anhydrous ammonia 148 47 — Ammonium nitrate 62 105 1,617 Ammonium sulfate 110 69 623 Urea 71 75 902 MAP 58 34 312 DAP 70 30 574 TSP Neutral 10 — Neutral 116 283 Potassium sulfate Neutral 46 92 1Source: CPHA, 2002. 2Equivalent per 100 lb of each material. 3Measure of the salt contribution by a fertilizer material to that produced by and equivalent weight of sodium nitrate (relative value of 100).

Module 10: Commercial Fertilizers and Soil Amendments 11 osmotic pressure increases. Fertilizers solubility for some fertilizers are given in with high salt indices are more likely Table 4 and are represented as pounds of to cause injury to seedlings and roots fertilizer material that will dissolve in 100 than fertilizers with low salt indices. In gallons of water. general, N and K fertilizers have much Nearly all N, K, and S fertilizers higher salt indices than P fertilizers (Table are completely water soluble, meaning 4). Evaluating fertilizer salt indices is all of the available nutrient is soluble. particularly important when applying The solubility of P fertilizers, on the starter (seed and fertilizer applied other hand, varies between carriers together) or drill-row applications. To and is dependent upon manufacturing avoid germination damage, recommended processes and composition. RP has

maximum rates for N + K2O starter and very low water solubility (less than 1% drill-row applications are given by crop P is water soluble), while treated RP in Fertilizer Guidelines for Montana fertilizers have relatively high solubility. Crops (Jacobsen et al., 2005). With proper For these fertilizers, total P availability is placement and timing of fertilizers calculated as the sum of water-soluble P (NM 11) and the advent of air drills, the and citrate-soluble P (Figure 7). Citrate potential for salt burn and crop damage soluble P is P which requires a weak can be minimized. acid (e.g., citrate) to become soluble. To achieve high crop yields, it is suggested So l u b i l i t y that superphosphates (TSP) contain Fertilizer solubility is a measure of high amounts of water-soluble P (greater how much fertilizer material will dissolve than 90%) and ammonium phosphate in water and is a property that strongly materials provide between 50 and 70% influences the availability of nutrients water-soluble P content (Bartos et al., to a crop and type of application method 1992). Because P availability is important to utilize. Highly soluble fertilizers will for early plant growth, it is recommended dissolve easily in water and the soil for banded starter fertilizers to contain solution, making nutrients available for high soluble forms of P (greater than 60% plant uptake. Highly soluble fertilizers generally). Most commercial P fertilizers are required for effective fertigation supply sufficient total P solubility to meet (application of fertilizer with irrigation these recommendations. Highly-soluble water) systems. Low solubility fertilizers, P fertilizers may be used in fertigation on the other hand, will not readily dissolve systems, although if the irrigation water in water, and nutrients may precipitate, contains high amounts of calcium (Ca) or becoming less available for plants. The magnesium (Mg), Ca/Mg-P compounds can form and precipitate. In addition to ineffective P fertilizing, this can 0-45-0 (TSP) cause scaling and plugging problems in equipment. The solubility of micronutrient Total available P2O5...... 45.0% fertilizers in water will vary and is related Water-soluble, percent of total to the process used in manufacturing and the primary product used as a available P2O5...... 89.0% micronutrient source. Because many Citrate-soluble, percent of total micronutrient fertilizers are manufactured from industrial by-products and are not avilable P2O5...... 11.0% water soluble, most require acid-treatment to increase solubility. Chelation also Figure 7. Example of the water-soluble P content improves metal solubility. Research has and citrate-soluble P content for TSP. shown that, under similar application rates,

12 Module 10: Commercial Fertilizers and Soil Amendments a highly soluble micronutrient fertilizer taken to prevent is able to supply more nutrients to a plant hazardous injury. than a similar fertilizer with lower water Urea solubility (Westfall et al., 2001). Thus, to In order for effectively supply micronutrients to crops, urea to be an it is recommended to obtain fertilizers effective source of with at least 50% micronutrient water plant-available N, solubility (Amrani et al., 1999). urease, an enzyme excreted by Sp e c i f i c Fe r t i l i z e r Re a c t i o n s microorganisms Anhydrous ammonia that convert urea Anhydrous ammonia (AA) is a liquid to NH +, must be 4 Figure 8. Injection of NH into the under pressure and a gas under normal active in the soil. 3 atmospheric conditions. AA is stored Urease activity soil. NH3 gas will quickly combine and transported as a liquid in a special is influenced with water to form plant-available pressurized tank and is injected into + by urease NH4 . the soil. When injected into the soil, the concentration, liquid AA expands into a gas and is readily temperature, moisture, and pH. Due to absorbed by soil moisture (Figure 8). This greater biological activity, there is usually expansion creates a band or ‘retention more urease present on plant surfaces and zone’ of NH3 gas around the injection crop residues than on bare soil. Therefore, point. The width of this retention zone no-till or conservation till systems may is dependent upon soil texture, water experience higher urease activity than content, and temperature. AA will expand traditionally tilled systems. Urease activity farther in sandy soils compared to finer- is greatest between 50oF and 100oF and textured soils due to larger pore openings slows when temperatures fall outside of between sand particles allowing NH3 this range. This is why urea-N availability gas through. Finer-textured soils also is delayed in cool soil temperatures have a higher exchange capacity, which with limited urease activity. Moist soil + better retains the NH4 formed from conditions and neutral to alkaline pH

NH3. The NH3 retention zone in moist values (pH 6.5-9) also increase urease soils is narrower than in dry soils, due to activity (Rachhpal-Singh and Nye, 1984). moisture absorbing NH3 and less air-filled High urease activity may further pores in moist soil (more water-filled influence NH3 volatilization following urea pores) that allow NH3 to expand. NH3 is application because of an increase in pH highly corrosive and may temporarily and a more rapid conversion of urea to sterilize microorganism populations in the + NH4 (Hargrove, 1988). For example, urea retention zone. This effect is short-lived, broadcast-applied to warm, moist soils however, and microbial activity will soon with high urease activity will result in a resume. + higher concentration of NH4 than soils To decrease NH3 volatilization, it is with less urease activity. If the moist soil recommended to incorporate AA into dries quickly and no additional water is moderately moist soils under calm + supplied to move the produced NH4 into conditions and cool soil temperatures. To the soil and attach to clay and organic avoid immediate loss of NH gas, ensure + 3 matter particles, there is more NH4 -N the injection slit completely closes behind subject to volatilization than in the low the knife. Additional guidelines for optimal urease activity soil. conditions to minimize NH3 volatilization are given in Table 3 of NM 3. AA requires Fixation In soils containing high amounts of special handling and precautions should be Ca or Mg (as many Montana and Wyoming

Module 10: Commercial Fertilizers and Soil Amendments 13 soils do), P can be ‘fixed’ and taken out minerals form in high pH, calcareous of solution to form insoluble Ca/Mg-P soils (Bell and Black, 1970). However, in compounds. This can affect the amount a field study conducted on P-responsive of P available for plant uptake. Studies calcareous soils in North Dakota, no have shown P availability and plant uptake yield differences were found in durum

increase when applied with a source of between MAP and DAP at 20 lb P2O5/ac + NH4 -N. This effect is attributed to the (Dahnke and Swenson, 1981). In summary, + acidifying effect of NH4 , causing P to be ammonium phosphate fertilizers applied more available in solution, and higher N directly and in contact with the seed levels in the plant, resulting in larger root may cause some germination problems masses that are able to take up more P (under certain environmental conditions), from the soil (Blair et al., 1971; Hanson thereby favoring the use of MAP over DAP + and Westfall, 1986). Larger granular due to MAP’s lower NH4 concentration. P fertilizers may also be beneficial in Additionally, MAP may remain somewhat reducing initial P fixation because larger more soluble than DAP in calcareous soils, granules contact less soil per unit of P at least immediately adjacent to fertilizer than small granules; therefore, dissolved granules. However, MAP and DAP applied P is less likely to precipitate with other to calcareous soils in the Northern Great elements such as Ca. Plains have been found to produce similar crop yields, indicating no differences MAP and DAP in agronomic effects for MAP and DAP As previously discussed, MAP and DAP (Dahnke and Swenson 1981). Modern air differ in pH and NH + content, which can 4 drills that create a sufficient separation cause different microsite reactions to between seed and fertilizer at the same occur when comparing the two P sources. time dilute any salt or NH + toxicity, so that NH will be produced in the microsites 4 3 germination or seedling damage are non- around ammonium phosphate granules, existent under most conditions. especially if the P fertilizer increases pH.

Because NH3 decreases seed germination through salt burn and toxicity, higher pH P fertilizers would be expected to increase Amendments seed germination injury. Presumably due and Their Reactions to this effect, spring wheat seedling injury Amendments are materials used to alter in Montana has been found to increase the chemical or physical properties of soil. in the order ammonium polyphosphate Examples of amendments include lime, < MAP < DAP < urea ammonium elemental sulfur, and gypsum. Organic

phosphate (UAP), which agrees with NH3 materials, such as , biosolids, and production being greatest with increasing are also used as soil amendments. pH (Jackson et al., 1983; Pairintra, 1973). Manure will be discussed in detail in NM Others have reported that DAP causes 13. greater stand damage than MAP in irrigated barley, but germination effects So i l pH can be minimized by applying no more Soil pH and amendments used to than 20 lb N/ac in 12 in. rows (Christensen manage either acid or alkaline soils were et al., 1977). In this study, there were no discussed in NM 8. Common amendments differences in yield in one year, and a 2.3 used to lower pH (acidify) are elemental o bu/ac lowered yield in DAP-applied soil in sulfur (S­), ferrous sulfate (FeSO4),

the second year. The lower pH immediately and aluminum sulfate (Al2(SO4)3). Soil adjacent to a MAP granule compared to a acidifying amendments are generally DAP granule has been found to decrease not cost effective in the long term for the rate that relatively insoluble Ca-P Northern Great Plains soils because of

14 Module 10: Commercial Fertilizers and Soil Amendments their high buffering capacity which very hard upon drying and the surface consistently maintains pH near 7.5-8. may be discolored by white salt deposits or Lime amendments are used to raise pH by dark organic matter that is carried up and include ground limestone (CaCO3), by water and deposited on the soil surface dolomitic limestone (CaMg(CO3)2), and after evaporation (historically referred to burned limestone (CaO). Properly applied, as ‘black alkali’ soils). liming can be an effective treatment Sodic soils can be amended either for acidic soils of this region. If needed, physically or chemically. Physical amendments to adjust pH should be treatment includes deep-plowing or applied prior to fertilization or during the ripping to increase permeability. Chemical fall before the next growing season. amendments usually contain calcium (Ca2+) which replaces Na+ on the exchange Sa l t a n d So d i u m Af f e c t e d So i l s site (clay or organic matter surface), Three types of salt-affected soils are 1) causing Na+ to be released to the soil saline; 2) sodic; and 3) saline-sodic. Saline solution and leached out of the root zone. soils contain excessive amounts of soluble Gypsum (CaSO4) is the most common salts that can impair plant productivity and economical amendment used on and cause soil quality to diminish. Saline sodic soils in Montana and Wyoming. soils occur as a result of water evaporating Gypsum is a relatively insoluble salt, with and salts in the water accumulating on less than 1% of the gypsum dissolving in or near the soil surface. Groundwater water. For this reason, gypsum is a long- with high salt levels can also cause saline acting but slow amendment for sodic soil soil conditions. White salt deposits on improvement. Applied gypsum should be the soil surface are a common property finely ground and well mixed with the of saline soils. Saline effects are most upper soil horizons so that its solubility prevalent in arid or semiarid regions, and rate of reaction are maximized including some areas of Montana and (Schafer, 1982). Other amendments Wyoming, where rainfall is not sufficient for sodic soils include calcium chloride for adequate of salts from the (CaCl2) and sulfur/sulfuric acid materials. soil surface beyond the root zone. As no CaCl2 is more chemical amendments or fertilizers can soluble than improve saline soils, the only effective gypsum, but ‘amendment’ for decreasing salinity is to also more leach excess salts with water, provided expensive. there is sufficient quantity of low-salt The addition water available and good soil drainage. of sulfuric Sodicity applies to soils with relatively acid (product low salt concentrations, but high amounts of oxidized of exchangeable sodium (Na+). Sodic sulfur) soils generally have a pH greater than frees up 8.5 and are characterized by their poor Ca2+ already physical structure and slow permeability, present in causing plant productivity to be limited calcareous Figure 9. Sodic soil showing shrink- + (Brady and Weil, 1999). Na causes soil soils, thereby swell effects due to the dispersion of particles and humus to disperse (spread displacing clay particles by Na+. When wet, the out), decreasing soil structure and Na+ (Schafer, aggregation and resulting in very slow 1982). soil swells because more water can be water movement in the soil. In turn, Sulfuric acid held by the dispersed particles. Upon this can cause expanding clays with high reacts more drying, the soil shrinks and a cracked, Na+ levels to exhibit shrink-swell effects quickly than polygonal-like pattern typically appears. (Figure 9). Additionally, sodic soils become gypsum, yet (Photograph compliments of J. Bauder, MSU). Module 10: Commercial Fertilizers and Soil Amendments 15 because it requires to work effectively, and manure application special handling (it may only be feasible when sufficient supply # is extremely caustic), is locally available. Q&A 3 sulfuric acid is not as commonly used in Heavy Metals in If a Montana study has agricultural settings. Fertilizers and Amendments found no accumulation Saline-sodic soils contain high Some fertilizers and amendments of metals in soil concentrations of may contain concentrations of trace both salts and Na+ and elements and heavy metals due to the following P fertilization, management processes mineralogy and manufacturing processes why is there a Montana are a combination of of the material or the addition of ‘waste- those described above. derived’ material (Mortvedt, 1987). Waste- rule regulating metal If attempts are made derived material refers to recyclable levels in fertilizers and to leach out soluble materials used for alternative purposes salts in saline-sodic (e.g., industrial by-products, biosolids). amendments? soils, as was discussed The presence of metals in fertilizers is of for saline soils, then concern as it can potentially lead to the Despite the findings of one exchangeable Na+ accumulation of toxic metals in fertilized study, heavy metals do exist concentrations and pH soils, adversely affecting livestock and in some fertilizers and pose a will likely increase and human health. Metals of concern in potential threat to livestock and sodic soil properties fertilizers and amendments include arsenic human health. Studies done will occur. Therefore, (As), cadmium (Cd), lead (Pb), and to a in other areas, including the for saline-sodic soils, lesser extent nickel (Ni) and zinc (Zn). The western U.S., have found metal attention should first first three are considered non-nutritive accumulations in P fertilized soils. be given to reducing metals as they provide no nutritional Additionally, as other western the concentrations of value for a plant. The latter two metals, states have enacted regulations exchangeable Na+ and however, are essential plant and animal for adulterated fertilizers, there then to the problem of micronutrients and high levels may not is a concern that fertilizers excess salts (Brady and necessarily be toxic. Fertilizer products containing excessive heavy metals Weil, 1999). containing P inherently contain metals, will be ‘dumped’ into Montana particularly Cd, which is a constituent of and other states that don’t have Or g a n i c Am e n d m e n t s RP. Manufacturing processes only remove regulating rules. Organic a small percentage of heavy metals from amendments, including RP, while the majority remains in the final compost, mulch, and product. RP-derived material from the biosolids, improve soil conditions by western U.S. generally contains higher Cd affecting the physical nature of the soil and other metal levels than eastern U.S. and providing a source of microorganisms, sources (Mortvedt, 1987). Micronutrient nutrients, and . sources may also contain naturally When applied to sodic soils, research occurring amounts of heavy metals has shown organic amendments to from the raw ore source and extraction successfully increase permeability processes. Simple N and K fertilizer through the aggregation of soil particles materials have relatively low heavy metal (Schafer, 1982). Fibrous crop residues will concentrations (Mortvedt, 1981). decompose slowly and be more effective Numerous field studies have been at increasing permeability than fast- conducted in Canada and the U.S. relating decomposing residues. Manure increases to heavy metal accumulation in soils and permeability by physically separating soil crops following long-term P fertilization, particles and increasing aeration. However, yet results are conflicting and appear to very large amounts of manure are required be dependent upon source of fertilizer

16 Module 10: Commercial Fertilizers and Soil Amendments material, application rates, location, and _ soil properties (e.g., texture, pH, organic 6.0 matter). An extensive study conducted _ Site I1 Fertilized 5.0 by Holmgren et al. (1993) across the Non-Fertilized U.S. found soils of the western U.S., 4.0 _ Note: All values are including Montana and Wyoming, to averages of 10 samples 3.0 _ have moderately high Cd levels (average * * * of 0.30 ppm) compared to other regions 2.0 _ of the country. Hypothesized causes for C o n c e t r a i ( m g / k ) * these data include soil parent material 1.0 _ * high in Cd or a greater use of western 0.0 RP-derived P fertilizer in the western Cd Cr Cu Ni Pb Zn U.S. Additionally, the study found general _ correlations to occur between metal 6.0 * accumulations and weathering processes _ Site I2 5.0 (highly weathered soils were lowest in metal concentrations) and soil texture 4.0 _ (most metals generally increased with _ * increasing clay concentrations). 3.0 * Another study looking at both soil and 2.0 _ plant tissue concentrations of heavy metals C o n c e t r a i ( m g / k ) following P fertilization resulted in mixed 1.0 _ * * * findings (Mortvedt, 1987). Some fertilized 0.0 soils had greater Cd levels than non- Cd Cr Cu Ni Pb Zn fertilized soils, while other sites showed _ no significant change in Cd levels between 6.0 fertilized and non-fertilized soils. Plant _ Site NI 5.0 tissue Cd concentrations did not differ between any of the fertilized and non- 4.0 _ fertilized sites. _ A study was conducted in Montana 3.0 * to assess metal concentrations following 2.0 _ * twenty years of DAP and/or TSP * * C o n c e t r a i ( m g / k ) fertilization. The study found that, in 1.0 _ * * general, fertilized soils did not have 0.0 significantly higher metal concentrations Cd Cr Cu Ni Pb Zn than non-fertilized soils in either irrigated (I1 and I2) or non-irrigated (NI) Figure 10. Effects of fertilization on DTPA-TEA soils (Figure 10). In most cases, non- extractable metal accumulation in the 0-15 cm depth fertilized soils had significantly higher of three Montana soils (Jones et al., 2002). concentrations of both available and total * indicate significance at P <0.05 metals (Jones et al., 2002). These findings indicate that long-term fertilization is In response to the presence of heavy not increasing metal concentrations in metals in fertilizers, some western Montana soils. The mixed results of these states, including Montana, have adopted studies and others suggest that while legislation and rules pertaining to the metal accumulation in soils and crops ‘adulteration’ of fertilizers or amendments following P fertilizer application is a by heavy metals (Q&A #3). The distribution potential problem, there are numerous of an adulterated fertilizer or amendment factors that can affect the magnitude of is prohibited within the statutes of the their accumulation. Montana Commercial Fertilizer Act;

Module 10: Commercial Fertilizers and Soil Amendments 17 however, adulteration is not defined. Administrative Rule of Montana (ARM) 4.12.620 (see http://www. Table 5. Maximum levels for agr.state.mt/US/programs/rules/) was formed in July 2003 to define the limits of fertilizer and amendment select metals in fertilizers and soil adulteration and outline the regulation processes amendments established by ARM for distribution within the state. ARM 4.12.620 states that fertilizers and amendments distributed 4.12.620. ppm per 1% ppm per 1% in the state are required to be registered by the Metals fertilizer distributor with the Montana Department of P2O5 of micronutrients of Agriculture and tested for adulteration by heavy Arsenic (As) 13 112 metals. Materials are considered adulterated when they contain metals in amounts that exceed Cadmium (Cd) 10 83 established levels (Table 5, Calculation Box # 2). Lead (Pb) 61 463 Those deemed adulterated will not be allowed to be How to use this table: Multiply the percent guaranteed distributed. P2O5 or sum of the guaranteed percentages of all To find information regarding heavy metal micronutrients in each product by the value in the concentrations of fertilizers and amendments, appropriate column in the table to obtain the maximum contact your fertilizer distributor. If metal allowable concentration (ppm) of these metals. A minimum value of 6.0 should be used for percent accumulation is suspected in your soil, periodically P O , and 1.0 for percent micronutrients. If a product testing soil for heavy metal accumulations may be 2 5 contains both P2O5 and micronutrients, calculate the beneficial. metal concentration for each and use the higher of the two resulting values as the maximum allowable metal Summary concentrations. Commercial fertilizers and soil amendments are important tools for nutrient and Wyoming, high pH and saline soils are more difficult in today’s agricultural industry. Fertilizers offer to amend due to the relatively high buffering essential nutrients in various contents, forms, and capacity of soils and low precipitation in this region. blends to meet an individual producer’s nutrient By understanding what each fertilizer or amendment requirements. Soil amendments are used to alter soil product offers with respect to nutrient availability, chemical or physical conditions for the improvement ease of handling and application, and reaction effects, of soil fertility and crop productivity. While some producers are better able to meet the needs of their chemical and organic amendments may improve growing crops. sodic and acidic soil conditions in Montana and

Calculation Box #2

Calculation: Maximum allowable metal concentration = % P2O5 or % micronutrients x allowable amount of metal Example: Under ARM 4.12.620, what is the maximum allowable Cd concentration for a bag of 15-30-15 that contains some micronutrients (Figure 1)?

From Table 5, allowable amount of Cd (ppm) for every 1% P2O5 = 10; and for every 1% micronutrients = 83.

% P2O5 x allowable amount of Cd = 30 x 10 = 300 ppm Cd % micronutrients = sum percentages of all micronutrients present in fertilizer = 0.02 (B) + 0.07 (Cu) + 0.15 (Fe) + 0.05 (Mn) + 0.0005 (Mo) + 0.06 (Zn) = 0.350% total micronutrients. Since % micronutrients is under the minimum value of 1% (giving a maximum Cd concentration=83

ppm), the value calculated from % P2O5 will be utilized to establish the maximum allowable Cd concentration = 300 ppm Cd.

18 Module 10: Commercial Fertilizers and Soil Amendments Hargrove, W.L. 1988. Evaluation of Pairintra, C. 1973. Influence of NH3 from References ammonia volatilization in the field. J. phosphate fertilizers on germination, Amrani, M., D.G. Westfall, and G.A. Prod. Agric. 1(2):104-111. seedling growth, and small plant yield Peterson. 1999. Influence of water of wheat (Driticum aestivum L.). solubility of granular zinc fertilizers Havlin, J.L., J.D. Beaton, S.L. Tisdale, Ph.D. Dissertation. Montana State on plant uptake and growth. J. of Plant W.L. Nelson. 1999. Soil Fertility and University. Bozeman, MT. Diss. Abstr. Nutr. 22:1815-1827. Fertilizers, 6th Edition. Upper Saddle 73:27,490. River, N.J. Prentice-Hall, Inc. 499p. Bartos, J.M., G.L. Mullins, J.C. Williams, Phillips, R. and K. Mathers. 2001. F.J. Sikora, and J.P. Copeland. Holmgren, G.G.S., M.W. Meyer, R.L. Fertilizer and natural gas. The 1992. Water-insoluble impurity Chaney, and R.B. Daniels. 1993. Fertilizer Institute. Accessed April effects on phosphorus availability Cadmium, lead, zinc, copper, and 7, 2003 at http://www.tfi.org/Media/ in monoammonium phosphate nickel in agricultural soils of the NaturalGasjan.doc. fertilizers. Soil Sci. Soc. Am. J. 56(3): United States of America. J. Environ. 972-976. Qual. 22:335-348. Rachhpal-Singh and P.H. Nye. 1984. The effect of soil pH and high urea Bell, L.C. and C.A. Black. 1970. Jackson, T.L., A.D. Halvorson, and B.B. concentration on urease activity in Crystalline phosphates produced Tucker. 1983. Soil fertility in dryland soil. J. Soil Sci. 35:519-527. by interaction of orthophosphate agriculture. In Dryland Agriculture, fertilizers with slightly acid and Agronomy Monograph, no. 23. ASA- Schafer, W. 1982. Saline and Sodic Soils alkaline soils. Soil Sci. Soc. Am. Proc. CSSA-SSSA. Madison, WI. in Montana. Bozeman, MT. Montana 34:735-740. State University Extension Service. Jacobsen, J., G. Jackson, and C.A. Bulletin 1272. Blair, G.J., C.P. Mamaril, and M.H. Miller. Jones. 2005. Fertilizer Guidelines 1971. Influence of nitrogen source on for Montana Crops. Bozeman, MT. Westfall, D.G., W.J. Gangloff, G.A. phosphorus uptake by corn from soils Montana State University Extension Peterson, and J.J. Mortvedt. 2001. differing in pH. Agron. J. 63:235-238. Service. EB 161. Organic and inorganic Zn fertilizers: Relative availability. Western Nutrient Brady, N.C. and R.R. Weil. 1999. The Jones, C.A. and J. Jacobsen. 2005. Management Conference Proceedings- Nature and Properties of Soils, 12th Effects of dust control coatings on Vol. 4. March 8-9, 2001. Salt Lake City, Edition. Upper Saddle River, NJ. phosphorus fertilizer dissolution and UT. p. 123-129. Prentice-Hall, Inc. 881 p. uptake. Commun. Soil Sci. Plant Anal. 34(13&14):1791-1801. Wolf, B., J. Fleming, and J. Batchelor. Christensen, N.W., J.D. Franklin, and 1985. Fluid Fertilizer Manual, Vol. C.M. Smith. 1977. Comparisons of Jones, C.A., J. Jacobsen, and S. Lorbeer. 1. National Fertilizer Solutions different ammonium phosphates— 2002. Metal concentrations in three Association. Peoria, IL. Influence on seedling injury, growth, Montana soils following 20 years of and yield of irrigated barley. Proc. 28th fertilization and cropping. Commun. Ann. Northwest Fert. Conf. Twin Falls, Soil Sci. Plant Anal. 33(9&10):1401- ID. p. 121-131. 1414. APPENDIX CPHA. 2002. Western Fertilizer Mortvedt, J.J. 1987. Cadmium levels in Bo o k s Handbook, 9th Edition. Danville, IL. soils and plants from some long-term Western Fertilizer Handbook, 9th Interstate Publisher, Inc. 356 p. soil fertility experiments in the United Edition. California Plant Health States of America. J. Environ. Qual. Association. 2002. Danville, IL. Dahnke, W.C. and L. Swenson. 1981. 16(2):137-142. Comparison of diammonium and Interstate Publishers. 351 p. (www. monoammonium phosphate. Soil Mortvedt, J.J., D.A. Mays, and G. Osborn. amazon.com) $50. Science Dept. Annual Rept. Fargo, ND. 1981. Uptake by wheat of cadmium Soil Fertility and Fertilizers, 6th North Dakota State University. and other heavy metal contaminants Edition. J.L. Havlin et al. 1999. Upper in phosphate fertilizers. J. Environ. Saddle River, NJ. Prentice Hall. 499 p. Fan, M.X. and A.F. Mackenzie. 1993. Qual. 10(2):193-197. Urea and phosphate interactions Approximately $100. in fertilizer microsites: Ammonia Overdahl, C.J. G.W. Rehm, and H. L. Manual. J. Benton Jones, volatilization and pH changes. Soil Meredith. 1991. Fertilizer Urea. Jr. 1998. Boca Raton, FL. CRC Press. Sci. Soc. Am. J. 57:839-845. Minneapolis-St. Paul, MN. University 149 p. Approximately $50. of Minnesota Extension Service. FO- Fenn, L.B. and S. Miyamoto. 1981. 00636. Accessed April 7, 2003 at http:// Ammonia loss and associated reactions www.extension.umn.edu/distribution/ of urea in calcareous soils. Soil Sci. cropsystems/DC0636.html. Soc. Am. J. 45:537-540. Overrein, L.N. and P.G. Moe. 1967. Hanson, R.L. and D.G. Westfall. Factors affecting urea hydrolysis and 1986. Orthophosphate solubility ammonia volatilization in soil. Soil transformations and availability from Sci. Soc. Am. J. 31:57-61. dual-applied nitrogen and phosphorus: Calcareous soil. Soil Sci. Soc. Am. J. 50:1368-1370.

Module 10: Commercial Fertilizers and Soil Amendments 19 x t e n s i o n a t e r i a l s Westcott, Mal. Professor. Western E M Agricultural Research Center, Protecting Our Water Resources: Acknowledgements Corvalis. (406) 961-3025. Environmental Stewardship [email protected] We would like to extend Strategies for Fertilizer Facilities. EB our utmost appreciation to the 131. Free. Wichman, Dave. Superintendent/ Research Agronomist. Central following volunteer reviewers Saline and Sodic Soils in Montana. Agricultural Research Center, wo provided their time and Bulletin 1272. Free. Moccasin. (406) 423-5421 dwichman@ insight in making this a better Soil Testing Procedures, Interpretation, montana.edu document. and Fertilizer Sources. MontGuide 198704AG. Free. We b Re s o u r c e s Dave Bertelsen, Wibaux County Fertilizer Guidelines for Montana Crops. http://www.back-to-basics.net/index.htm Extension, Wibaux, Montana EB 161. Free. Online source for a variety of soil Grant Jackson, Western Nutrient Management Modules (1-15) fertility information and resources. Triangle Agricultural All are online in PDF format in the Source: IMC-Agrico and Potash and category of ag and natural resources, Phosphate Institute (PPI). Research Center, Conrad, at http://www.msuextension.org/ Montana publications.asp http://www.farmresearch.com/ Dave Taylor, Montana Dept. Potash and Phosphate Institute Extension Materials can be obtained of Agriculture, Helena, from: (PPI) and Foundation for Agronomic Research (FAR) Web site. Montana MSU Extension Publications P.O. Box 172040 http://www.tfi.org/ Terry Tindall, J.R. Simplot Bozeman, MT 59717-2040 The Fertilizer Institute Web site Company, Boise, Idaho (406) 994-3273 offering up-to-date information on Please enclose $1 for shipping of free the fertilizer industry in the U.S. and http://www.msuextension.org/ publications. abroad. publications.asp http://www.fluidfertilizer.com/ Montana State University Extension See also Web Resources below for online Publications ordering information for ordering information. Fluid Fertilizer Foundation (FFF) Web printed materials. site. Includes information and articles regarding the fluid fertilizer industry. http://landresources.montana.edu/ Pe r s o n n e l FertilizerFacts/ Engel, Rick. Associate Professor. Montana http://www.epa.gov/oppt/pubs/fertilizer. State University, Bozeman. (406) 994- pdf Fertilizer Facts summarizing fertilizer 5295. [email protected] findings and recommendations Background Report on Fertilizer Use, based on field research conducted in Jackson, Grant. Professor. Western Contaminants, and Regulations’ from Montana by Montana State University Triangle Agricultural Research the U.S. Environmental Protection personnel. Center, Conrad. (406) 278-7707. Agency (EPA), 1999. [email protected] http://agr.mt.gov/pestfert/fertilizer.asp Jones, Clain. Extension Soil Fertility The Montana Department of Specialist. Montana State University, Agriculture Web site covering various Bozeman. (406) 994-6076. clainj@ agricultural issues in Montana, montana.edu including news, programs, and registration and licensing information.

Copyright © 2003 MSU Extension. Reprinted 2009. We encourage the use of this document for non-profit educational purposes. This document may be reprinted if no endorsement of a commercial product, service or company is stated or implied, and if appropriate credit is given to the author and MSU Extension. To use these documents in elec- tronic formats, permission must be sought from the Extension Communications Coordinator, 115 Culbertson Hall, Montana State University-Bozeman, Bozeman, MT 59717; (406) 994-5132; E-mail - [email protected].

The programs of MSU Extension are available to all people regardless of race, creed, color, sex, disability or national origin. Issued in furtherance of cooperative extension work in agriculture and home economics, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Douglas L. Steele, Vice Provost and Director, Extension, Montana State University, Bozeman, MT 59717.