Nutrient Management in Field Crops MSU Fertilizer Recommendations Crop*A*Syst 2015 Nutrient Management Training George Silva - silvag@msu.edu Eaton, Ingham, Barry and Livingston Counties
17 Essential Plant Nutrients Macronutrients Nitrogen (N), Phosphorus(P), and Potassium(K) Required in large amounts and likely to be deficient (BIG 3) Carbon (C), Oxygen (O), and Hydrogen(H) are derived from atmospheric carbon dioxide and soil water Secondary Nutrients Calcium (Ca), Magnesium(Mg) and Sulfur(S) Required in large amounts but less likely to be deficient Micronutrients Manganese (Mn), Zinc (Zn), Boron (B), Copper (Cu), Iron (Fe), Molybdenum (Mo), chlorine (Cl), Nickel (Ni) Required in trace amounts
Nutrient Stewardship Practices for Michigan Phosphorus contamination of surface water Nitrate contamination groundwater and surface water MSU Fertilizer Recommendations - based on many years of field testing and taking into consideration the economic, agronomic and environmental implications for Michigan
Bray P1 in ppm 100 Average soil test P levels on Michigan farm fields Medium MSU P soil Soil test Test lab Levels from 1962- in Michigan 2007 75 50 Ideal range for crop growth 48 ppm 2012 25 0 1962 1967 1972 1977 1982 1987 1992 1997 2002 2007 Complex chemical reactions in the soil unique to phosphorus Previous practices leading to buildup
Nitrogen deficiency Uniformly light green or yellowing of leaves
Nutrient mobility inside the plant Very mobile Nitrogen, Phosphorus, Potassium, Magnesium (Deficiency symptoms appear first in older leaves and quickly spread throughout the plant) Relatively immobile - Manganese, Sulfur, Copper, Iron, Zinc, Calcium, Boron, Molybdenum (Deficiency symptoms first appear in new growth but do not readily translocate to old growth).
Nitrogen deficiency Uniformly light green and yellowing of leaves (firing)
Manganese (micronutrient) deficiency Yellowing between leaf veins
Nutrient Management - Determining right rate is critical Soil testing basis for fertilizer recommendations Deficiency symptoms appear too late and not entirely reliable
Why soil test? Ability of soil to supply nutrients Indicate potential deficiencies, excessive or imbalances Nutrient carrying capacity of the soil (CEC) Soil ph (ideal 6.5 6.8) Fertilizer recommendation for a specified yield goal (average of 5 years)
Soil sampling most important aspect of soil testing Sampling depth - 8-9 inches (No-till additional sample at 0-3 inch)
A sketch map indicating each soil unit/management zone
Grid soil sampling expensive but variable rate application
Basis for MSU fertilizer recommendations (NPK) P and K Buildup, Maintenance and Drawdown Approach (page 12) N Maximum Return to N (MRTN) Approach (page 11) Pub. E 2904 Nutrient Recommendations for Field Crops in Michigan
Crop response curve to soil test level Diminishing Returns Establish Critical soil test level depending on nutrient and crop (15-30 ppm for corn and soybeans) Relative soil test value Critical soil test value = The point where yield reaches 95-97% of maximum = economic optimum return on investment
Buildup, Maintenance and Drawdown Attain the critical level by adding P (15 to 30 ppm) corn and soybean Maintain by adding just the crop removal every year (page 8) Drawdown by reducing P rates p 15-30 ppm corn and soybean 25-40 ppm wheat and alfalfa Above adequate 65% of Michigan soils tested for P Low Low 15 30 ppm High
Maintenance rate Phosphorus and potassium crop removal rates Crop Yield lb P2O5/A removed lb K2O/A removed Corn 180 Bu 67 48 Soybean 45 Bu 36 63 Wheat 75 Bu 47 28 Alfalfa 4 Tons 52 200
Buildup, Maintenance and Drawdown Attain the critical level by adding P (15 to 30 ppm) corn and soybean Maintain by adding just the crop removal every year (page 8) Drawdown by reducing P rates p 15-30 ppm corn and soybean 25-40 ppm wheat and alfalfa Above adequate 65% of Michigan soils tested for P Low Low 15 30 ppm High
MSU Soil Test Lab Report Big three N, P, K Below optimum (Buildup ) Optimum (Maintenance) Above Optimum (Drawdown) (Buildup) (Maintenance) (Drawdown) Background Analysis Features: Soil ph Nutrient levels CEC Lime recommendation No test for N N, P, K, Mg and micronutrient recommendations for the expected yield N and P as starter * Recommendations Footnotes
Right placement critical Starter - 2x2 band placement at planting is the best (less contact with soil)
When P 2 0 5 exceed 60 ppm the starter P is turned off Only starter N is needed * *
Agronomic, economic and environmental considerations
Soil Phosphorus Buffering Capacity Soil test P changes very slowly with P additions or removals Average of 18 lb. P 2 O 5 crop removal needed to reduce P test by 1 ppm (A 180 bu corn crop removing 60 lb. P 2 O 5 will reduce soil P by 4 ppm) Wisconsin example: Soil test before the start of a 6-year rotation = 75 ppm = excessively high Soil test after the 6-year rotation with not P fertilizer = 57 ppm (18 ppm change) still excessively high Crop removal by corn, oats and alfalfa in 6-yrs = 330 lb/a. Crop removal per unit change in soil test =330/18 = 18 Buffering capacity is 18.
* Mg < 50 ppm in fine textured soils or <35 ppm on sandy soils When Mg is < 3% exchangeable bases When exchangeable K exceeds Mg
* * * When ph exceeds 7 - testing for Mn and Zn Is suggested Optimum ph range is 6.5-6.8
Effect of soil ph on nutrient availability on a mineral soil
Liming Excellent investment Pub: E 471 Lime for Michigan Soils
Liming Excellent investment
MSU Fertilizer Recommendations for Field Crops P and K Buildup, Maintenance and Drawdown Approach (page 12) N for corn Maximum Return to N (MRTN) Approach (page 11)
Maximum Returns to N (MRTN) Approach - Corn 1970-1.2 lb N per bushel of corn eg. 150 bu = 180 lbs N/A 2012-0.8 lb N per bushel of corn eg. 150 bu = 120 lbs N/A New corn hybrids are more efficient in utilizing N
MRTN - rate is based on Yield goal Previous crop Price of N and price of corn*
Gross Revenue to N Determining the economic optimum rate where net revenue is highest Gross Revenue to N fertilizer cost = Net revenue to N N expensive n N - cheaper Change in optimum fertilizer rate as cost of N changes
Nitrogen rate is determined by yield goal, previous crop and price of fertilizer/corn price (Page 11) Yield Goal >181 151-180 >181 151-180 * Slow acceptance by MI farmers
General corn N Guidelines for Michigan Apply about 30 40 lb N at planting Apply the rest as a June sidedress application Diagnostic tests PSNT - if manure has been applied or alfalfa history Chlorophyll meter with N reference plots End of season stalk test for post season evaluation
Interpretation of soil test reports from other labs Soil test reports from A & L Lab Use the fertrec program to generate MSU recommendations maec.msu.edu/fertrec Units should be same Bray P1 ppm = 0.65* Mehlich 3 IPC ppm
MSU Fertrec Program maec.msu.edu/fertrec
A & L Labs and MSU fertilizer rates compared Example: PF1 Corn Yield goal 150 bu/a* Previous crop - Soybean Nutrient MSU (lb/a) A & L (lb/a) Limestone (Ton/A) 0 0 N 95 145 P2O5 55 70 K2O 40 90 Mg 0 0 Zn 0.4 2.0 Mn 0 0 B 0 0 A & L Lab - N, P and K levels are usually higher compared to MSU
MSU and A & L Labs fertilizer rates compared Example PF2 Corn Yield goal 180 bu/a * Previous crop - Soybean Nutrient MSU (lb/a) A & L (lb/a) Limestone (Ton/A) 0 0 N 120 180 P2O5 0 35 K2O 0 45 Mg 0 0 Zn 2.9 3.5 Mn 3.3 3.0 B 0 0
MSU and A & L Labs fertilizer rates compared Example PF3 Corn Yield goal 175 bu/a Previous crop - Alfalfa Nutrient MSU (lb/a) A & L (lb/a) Limestone (Ton/A) 1.6 1.0 N 105 140 P2O5 95 110 K2O 65 185 Mg 0 0 Zn 0 1.5 Mn 0 0 B 0 0.5 N, P K usually higher compared to MSU
How about plant tissue tests? Generally not practiced in field crops Soil test for sulfur not effective Rapid plant sampling techniques may be available in the future Chlorophyll meter End of season cornstalk test
Nutrient Sufficiency Ranges Established for specific plant tissue and specific growth stage
Established NUTRIENT for specific plant SUFFICIENCY tissue at the right growth RANGES stage A & L Labs
Chlorophyll Meter as a tool for N Management No sampling (Non destructive test) Need to establish well fertilized N reference plots (side by side comparison) In season application with irrigation water or high booms until tassel fine tune the last 40 lbs
End of Season Cornstalk Test
End of Season Cornstalk Test N03-N accumulate or deplete in the stalk based on N availability during the season Done 2-3 weeks after black layer is formed in 90% of kernels Provides an overall assessment of N management used for corn Guide for next year Sensitive to dry and wet seasons *
Fertilizer Grade Minimum guarantee on a weight basis N, P, K Both granular and liquid fertilizer A 100 lb bag of 10-10-10 fertilizer contains 10 lbs nitrogen, 10 lbs phosphate and 10 lbs potash A 100 lb bag of 46-0-0 fertilizer contains 46 lbs nitrogen, 0 lbs phosphate and 0 lbs potash A 100 lb bag of 0-0-60 fertilizer contains 0 lbs nitrogen, 0 lbs phosphate and 60 lbs potash If the recommendation is only for 120 lb/a K2O, then use a 200 lb of 0-0-60.
Common N P K fertilizers Common Fertilizer Grade Nutrient Cost $/ton fertilizer* Urea 46-0-0 N 564 Anhydrous Ammonia 82-0-0 N 785 UAN (L) 28% N 385 Triple Super Phosphate 0-46-0 P205 614 Muriate of Potash 0-0-60 K20 630 Diammonium Phosphate (DAP 18-46-0 N and P 634 Monoammonium Phosphate (MAP) 11-48-0 N and P 704 Ammonium Polyphosphate (L) 10-34-0 N and P 849 Bulk 19-19-19 N, P and K 615 Bulk 6-24-24 N, P and K 627 Bulk 16-35-5 + Zn + S N, P, K, Zn, S 726
Liquid fertilizers UAN (Urea-ammonia nitrate) 28%N 10-34-0 (Ammonium polyphosphate) Analysis Weight (lb) per US Gallon 28-0-0 UAN 10.65 10-34-0 11.60 Example 1. 28-0-0 fertilizer used as starter or sidedress 100 lbs of 28-0-0 contain 28 lbs N 10.65 lbs (1 gal) contain (28/100) * 10.65 = 2.98 lb N 10 gal of 28-0-0 will contain 2.98* 10 = 30 lb N