This publication provides recommendations for nitrogen, phosphorus, potassium, secondary, and micronutrient requirements of South Dakota soils. Information on fertilizer application and guidance for fertilizing reduced and no-till wheat is also included

Carson, Paul

Fixen, Paul

Gerwing, Jim

Golderman, Ron

English

Public Research Access Institutional Repository and Information Exchange

South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange SDSU Extension Fact Sheets SDSU Extension 1983 Fertilizing Wheat Jim Gerwing Paul Fixen Paul Carson Ron Golderman Follow this and additional works at: https://openprairie.sdstate.edu/extension_fact Recommended Citation Gerwing, Jim; Fixen, Paul; Carson, Paul; and Golderman, Ron, "Fertilizing Wheat" (1983). SDSU Extension Fact Sheets. 1466. https://openprairie.sdstate.edu/extension_fact/1466 This Fact Sheet is brought to you for free and open access by the SDSU Extension at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in SDSU Extension Fact Sheets by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact michael.biondo@sdstate.edu. Historic, archived doculllent Do not assume content reflects current scientific knowledge, policies, or practices. SDSU ® Extension For current policies and practices, contact SDSU Extension Website: extension.sdstate.edu Phone: Email: 605-688-4 792 sdsu.extension@sdstate.edu SDSU Extension is an equal opportunity provider and employer in accordance with the nondiscrimination policies of South Dakota State University, the South Dakota Board of Regents and the United States Department of Agriculture. FS 677 ( Fertilizing Wheat Jim Gerwing, Extension agronomist, soils Paul Fixen, Assistant professor, plant science Paul Carson, Professor, plant science Ron Gelderman, Manager, Soil & Plant Analysis LHboratory High wheat yields require large quantities of available plant food. For example. each bushel of spring, winter, or durum wheat takes up approximately 2.4 lb nitrogen [N) .. 8 lb phosphorus (P,O,). and 1.9 lb potassium (K,O), in addition to the secondary and trace elements needed. There are at least 13 mineral elements necessary for plant growth: nitrogen, phosphorus and potassium (the primary plant foods); calcium. magnesium. and sulfur (the secondary nutrients); and boron. chlorine. copper, iron. manganese. molybdenum. and zinc (the micronutrients). Few (if any) soils can consistently provide the levels of all essential nutrients necessary to assure maximum potenti;:il yields. Therefore. some fertilizer is often needed. The best fertilizer rate will depend on existing soil fertility levels. yield desired. and past management. Nitrogen The amount of actual nitrogen recommended for a desired yield can be determined by subtracting the nitrate-nitrogen soil test values from the total nitrogen requirement shown in Table 1. If a deep (0-2 ft) nitrate-nitrogen soil test is not taken, nitrogen needs can be estimated using the soil organic matter level and the formula found in the footnote al the bottom of Table 1. The organic matter lest does not measure the wide fluctuations of available nitrogen in soils. and its use may result in recommendations for more or less fertilizer nitrogen than the crop actually needs. · Nitrogen fertilizer is not normally used as extensively on winter wheat as it is on spring wheat. Winter wheat is traditionally seeded in fallowed soils that will provide a 2-year soil nitrogen supply. Nevertheless, nitrogen fertilizer often will be profitable on fallowed fields seeded to either. Where winter or spring wheal is seeded on soil cropped the previous year, higher rates of nitrogen are usually needed. Nitrogen in excess of the amount needed for optimum plant growth and grain formation will usually result in higher protein levels. Time of application can also affect final results. In general. nitrogen applied early improves yield, nitrogen applied late [early heading) increases protein levels. However. climate variation and cash market premiums have to be considered. It is difficult to justify use of nitrogen solely to raise protein content. Table 1. Nitrogen recommendations. Yield goal. bu/A 25 35 45 55 65 75 Soil plus fertilizer nitrogen required 1, lb/ A (0-2 ft) 60 84 108 132 156 180 'Fertilizer nitrogen to apply is equal to the value in the table minus soil nitrate-nitrogen to a 2-ft depth. To estimate the fertilizer nitrogen needed without a 2-ft nitrate-nitrogen test. use the following formula based on the organic matter test: Required nitrogen minus 30. 45, or 60 lb for a low (less than 2.5%). medium (2.5-4.0%). or high (more than 4.0%) organic matter lest. respectively. If the previous crop was black fallow. subtract an additional 45 lb from each category. Phosphorus Phosphorus requirements are similar for winter ;rnd spring wheat grown ·on either fallow or non-fallow land. Readily avHilHble soil reserves of phosphorus do not build.up in fallow, HS does nitrate-nitrogen. Soil phosphorus levels will not fluctuH le from high lo low in 1 or 2 years. HS will nitrnle-nitrogen. Nnither will thciy changn from low to high, unless unusuHlly high mies of fortilizcir :irn applied. Phosphorus is converted to less availabl() forms whcm mixcid extensively with soil. This is part of the reason phosphorus fertilizer is more effective when applied with the seed in a band with a drill attachment than when broadcast ,md worked into the soil. Phosphorus fertilizer recommendations Hre given in Table 2. Small amounts of phosphorus placed with the seed hHv() occasionally increased wheat yields Ht high and very high soil test levels. Ten pounds of phosphorus (P,O°,) applied as a starter on these soils m;:iy be necessary for maximum yields. Table 2. Phosphorus recommendations. Soil test phosphorus. lb/A V. low Low Med. High V. high 0-5 6-15 16-25 26-40 41 + Yield goal. bu/A 3 10 20 33 41 lb P,O,/A recommended ' 25 26 25 20 10 0 35 35 32 26 10 0 45 44 40 31 13 0 55 52 47 36 15 10 65 61 55 42 18 10 75 70 62 47 21 10 'Recommendations listed are for the center of each soil test range. Potassium Potassium uptake requirements closely match -those of nitrogen but greatly exceed those of the other essential elements. Fortunately. most South Dakota soils contain high levels of available potassium. There are. however. a number of fields (particularly in the eastern third of the stale) that are low in this nutrient and receive soil test recommendations for potassium fertilizer use. Potassium fertilizer recommendations are given in Table 3. Table 3. Potassium recommendations. Soil test potassium, lb/A Low Med. High V. high 0-100 101-200 201-350 351 + Yield goal, bu/A 50 150 275 351 lb K2O/ A recommended' 25 33 32 0 0 35 47 43 0 0 45 61 53 0 0 55 76 63 0 0 65 90 73 0 0 75 104 83 19 0 'Recommendations listed are for the center of each soil test range. Secondary and micronutrients Secondary and micronutrients are as essential as the three primary plant foods for high yield levels. Most South Dakota soils have adequate available reserves of these nutrients. SDSU research has not shown significant profitable yield increases from fertilizer containing these nutrients. This may change with continued cropping and release of hew varieties. Fertilizer application Phosphorus and potassium should be applied before seeding and incorporated by tillage. injection. or with the seed at planting. Broadcast phosphorus rates can be reduced by a third when applied with a grain drill fertilizer attachment in a band in contact with or close to the seed. Nitrogen can be applied anytime prior to stooling with equal results. Thinner plant stands or reduced seedling vigor can occur if too much nitrogen and/or potash are placed in contact with the seed. This type of injury happens more easily in dry or sandy soils. The total amount of actual nitrogen plus potash placed with the seed in a drill attachment (6-inch row spacing) should be kept below 25 lb/ A in such soils. If either urea or DAP (18-46-0) nitrogen sources are used. limit drill applications to 12 lb/ A. Reduce these values correspondingly for wider row widths. These drill application amounts can be doubled for heavier textured, moist soils. Topdressed nitrogen after seeding should be applied before the stooling stage for best results. Lack of rainfall aft~r topdressing can make it less effective than preplant incorporation. Topdress applications of liquid nitrogen are as effective as dry nitrogen when applied prior to stooling. Liquid nitrogen rates in excess of 25 lb actual nitrogen per acre can cause considerable leaf burn. Rates greater than 50 lb/A may cause enough leaf burn to reduce yield. Liquid nitrogen should not be applied once the flag leaf emerges. Fertilizing reduced and no-till wheat Limited adjustments in fertilizer rates and placement may be necessary with reduced tillage. Available nitrogen levels in soil are usually lower. resulting in higher nitrogen fertilizer needs. The deep (0-2 ft) nitrate-nitrogen soil test will normally measure changes in available soil nitrogen levels regardless of tillage. If the deep soil test is not taken and nitrogen recommendations are made using the less accurate organic matter test (Table 1. footnote 1). nitrogen recommendations should be increased 30 lb/A from the calculated values. Surface residues and fewer opportunities for incorporation increase the potential for volatilization losses from surface applied urea. Nitrogen may also be tied up by surface residues. Incorporation or injection of nitrogen fertilizer. therefore. will often result in more efficient nitrogen use. Topdressed phosphorus fertilizers will remain near the surface with reduced and no-tillage systems. If test levels are low or conditions are dry. deeper incorporation. injection. or starter applications may be necessary. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the USDA. Richard A. Battaglia, Director of SDCES, Brookings. Reference to any products in this publication is not an endorsement. Persons using such products assume responsibility for their use. Educational programs and materials of-fered without regard to age, race, color, religion, sex, handicap, or national origin. An Equal Opportunity Employer. File: 3.3-2M-12-83-2.5Mrpt-3-85mb-ES 135-93. ( ( ( 

Fertilizing Wheat

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Fertilizing Wheat

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