Nutrient Management in Field Crops MSU Fertilizer Recommendations Crop*A*Syst 2015 Nutrient Management Training

Transcription

1 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

2 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

3 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

4 Bray P1 in ppm 100 Average soil test P levels on Michigan farm fields Medium MSU P soil Soil test Test lab Levels from in Michigan Ideal range for crop growth 48 ppm Complex chemical reactions in the soil unique to phosphorus Previous practices leading to buildup

5 Nitrogen deficiency Uniformly light green or yellowing of leaves

6 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).

7 Nitrogen deficiency Uniformly light green and yellowing of leaves (firing)

8 Manganese (micronutrient) deficiency Yellowing between leaf veins

9 Nutrient Management - Determining right rate is critical Soil testing basis for fertilizer recommendations Deficiency symptoms appear too late and not entirely reliable

10 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 ) Fertilizer recommendation for a specified yield goal (average of 5 years)

11 Soil sampling most important aspect of soil testing Sampling depth inches (No-till additional sample at 0-3 inch)

12 A sketch map indicating each soil unit/management zone

13 Grid soil sampling expensive but variable rate application

14 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

15 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

16 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 ppm corn and soybean ppm wheat and alfalfa Above adequate 65% of Michigan soils tested for P Low Low ppm High

17 Maintenance rate Phosphorus and potassium crop removal rates Crop Yield lb P2O5/A removed lb K2O/A removed Corn 180 Bu Soybean 45 Bu Wheat 75 Bu Alfalfa 4 Tons

18 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 ppm corn and soybean ppm wheat and alfalfa Above adequate 65% of Michigan soils tested for P Low Low ppm High

19 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

20 Right placement critical Starter - 2x2 band placement at planting is the best (less contact with soil)

21 When P exceed 60 ppm the starter P is turned off Only starter N is needed * *

22 Agronomic, economic and environmental considerations

23 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.

24 * Mg < 50 ppm in fine textured soils or <35 ppm on sandy soils When Mg is < 3% exchangeable bases When exchangeable K exceeds Mg

25 * * * When ph exceeds 7 - testing for Mn and Zn Is suggested Optimum ph range is

26 Effect of soil ph on nutrient availability on a mineral soil

27 Liming Excellent investment Pub: E 471 Lime for Michigan Soils

28 Liming Excellent investment

29 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)

30 Maximum Returns to N (MRTN) Approach - Corn lb N per bushel of corn eg. 150 bu = 180 lbs N/A lb N per bushel of corn eg. 150 bu = 120 lbs N/A New corn hybrids are more efficient in utilizing N

31 MRTN - rate is based on Yield goal Previous crop Price of N and price of corn*

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33 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

34 Nitrogen rate is determined by yield goal, previous crop and price of fertilizer/corn price (Page 11) Yield Goal > > * Slow acceptance by MI farmers

35 General corn N Guidelines for Michigan Apply about 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

36 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

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38 MSU Fertrec Program maec.msu.edu/fertrec

39 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 P2O K2O Mg 0 0 Zn Mn 0 0 B 0 0 A & L Lab - N, P and K levels are usually higher compared to MSU

40 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 P2O K2O 0 45 Mg 0 0 Zn Mn B 0 0

41 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) N P2O K2O Mg 0 0 Zn Mn 0 0 B N, P K usually higher compared to MSU

42 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

43 Nutrient Sufficiency Ranges Established for specific plant tissue and specific growth stage

44 Established NUTRIENT for specific plant SUFFICIENCY tissue at the right growth RANGES stage A & L Labs

45 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

46 End of Season Cornstalk Test

47 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 *

48 Fertilizer Grade Minimum guarantee on a weight basis N, P, K Both granular and liquid fertilizer A 100 lb bag of fertilizer contains 10 lbs nitrogen, 10 lbs phosphate and 10 lbs potash A 100 lb bag of fertilizer contains 46 lbs nitrogen, 0 lbs phosphate and 0 lbs potash A 100 lb bag of 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

49 Common N P K fertilizers Common Fertilizer Grade Nutrient Cost $/ton fertilizer* Urea N 564 Anhydrous Ammonia N 785 UAN (L) 28% N 385 Triple Super Phosphate P Muriate of Potash K Diammonium Phosphate (DAP N and P 634 Monoammonium Phosphate (MAP) N and P 704 Ammonium Polyphosphate (L) N and P 849 Bulk N, P and K 615 Bulk N, P and K 627 Bulk Zn + S N, P, K, Zn, S 726

50 Liquid fertilizers UAN (Urea-ammonia nitrate) 28%N (Ammonium polyphosphate) Analysis Weight (lb) per US Gallon UAN Example fertilizer used as starter or sidedress 100 lbs of contain 28 lbs N lbs (1 gal) contain (28/100) * = 2.98 lb N 10 gal of will contain 2.98* 10 = 30 lb N

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