MANAGING FERTILITY FOR PROTEIN IN SMALL GRAINS

Transcription

1 Juliet M. Marshall Meeting Crop Needs MANAGING FERTILITY FOR PROTEIN IN SMALL GRAINS 1

2 Outline What are proteins? Importance of N to the crop Estimating Nitrogen Availability Predicting Crop Needs Irrigated Wheat and Barley Dryland Wheat and Barley 2

3 What are Proteins? Organic compounds composed of amino acids The order of the type of amino acids determines the structure and folding Have multiple layers of structure (1, 2, 3, 4) 3

4 Cysteine Methionine 4

5 Cysteine SH HS H2 S S 5

6 Proteins form enzymes, are structural components (cell, muscle, other tissue), cell signaling, immune response, etc Are important components of seeds and compose the gluten fraction in wheat 6

7 Importance of Nitrogen to the Crop Meeting the nutrient requirements for yield Meeting fertility required for quality Not enough N = reduced yields and quality = LOSS $$$ Too much N = late maturity, lodging, disease susceptibility, yield reductions, potential loss with leaching or high rainfall events = LOSS $$$ 7

8 Importance of Nitrogen to the Crop Meeting the nutrient requirements for yield Meeting fertility required for quality Balanced diet means healthy plants; healthy plants means stress tolerance Consider phosphorus fertilizer with nitrogen at planting for optimum root growth Also consider Sulfur it s a critical component of protein! 8

9 Estimating Nitrogen Availability 1) Level of residual inorganic soil N 2) Mineralizable N 3) Previous crop residues 4) Realistic yield estimates 9

10 Estimating Nitrogen Availability 1) Level of residual inorganic soil N 2) Mineralizable N 3) Previous crop residues 4) Realistic yield estimates 10

11 Estimating Nitrogen Availability Level of residual inorganic soil N SOIL TEST! Sample 1 2 weeks prior to planting Sample TWO depths for N 0 12 and Sample at least 20 areas representative of field Send to reputable lab 11

12 Estimating Nitrogen Availability Level of residual inorganic soil N Nitrate N NO3 Ammonium N NH4 + Add all N amounts in 1 st two feet of soil NO3 in ppm = 41 NH4 + in ppm =

13 Estimating Nitrogen Availability Level of residual inorganic soil N Multiply ppm by 3.6 to get lbs N per acre 51 x 3.6 = 148 lbs N per acre If test report is in lbs add NO3 and NH4 + amounts from 1 st two feet 51 13

14 Estimating Nitrogen Availability 1) Level of residual inorganic soil N 2) Mineralizable N 3) Previous crop residues 4) Realistic yield estimates 14

15 Estimating Nitrogen Availability Mineralizable N Release of nitrogen from organic matter Usually of minimal importance in low organic matter soils Is difficult to estimate 45 lb N per acre often used can be lbs Add 45 lbs N per acre of fertilizer reserve 15

16 Estimated Nitrogen Contribution to Wheat Crop from Soil Organic Matter Decomposition Based on Percent Organic Matter in the Surface Soil Organic Matter Content N Contribution % lb/a < >

17 Estimating Nitrogen Availability Potatoes, sugarbeets, onions, peas, beans use soil test N Grain straw has very low amounts of N additional N needed to facilitate tissue decomposition Fall plowed alfalfa very slow decomposition rates Add 15 lbs N per acre for each ton of straw residue up to 50 lbs Subtract lbs per acre from soil test N 17

18 Estimating Nitrogen Availability Realistic yield estimates 1) What can you reasonably expect based on your soil, environmental conditions, and management practices? 2) Variety yield potential, water management, pest control, lodging control 3) Use expected yield to estimate crop demand 7 year average, minus the highest and lowest 18

19 Estimating Nitrogen Availability Manures PNW239 How to Calculate Manure Application Rates in the Pacific Northwest Send a sample for laboratory testing! Accurately calibrate spreader Don t forget other sources! Water No3 levels? 19

20 Calculating N Contribution From Irrigation Water Water Application Rate (acre feet) N in water (ppm) lbs N / acre

21 Estimating Nitrogen Availability Making the calculations for total N 1) Level of residual inorganic soil N 2) Mineralizable N (OM credit) 3) Previous crop residues ) Realistic yield estimates total = bu/a x 2 lbs N/bu = 280 lbs N/A required = 87 lbs N/A needed 21

22 Outline Importance of N to the crop Estimating Nitrogen Availability Predicting Crop Needs Dryland Wheat and Barley Irrigated Wheat and Barley 22

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24 Application Timing Excessive nitrogen applications applied preplant should be avoided since nitrogen fertilizer efficiency is about 20% less when applied preplant compared to within season applications. 24

25 Estimating Wheat N Needs Requirements are different for soft wheats versus hard wheats, irrigated versus dryland, hard whites versus hard reds 25

26 Estimating Irrigated SWW Wheat N Needs About pounds of nitrogen should be available for each bushel of attainable yield Split applications recommended on sandy soils, or where economically feasible. 60% preplant 40% tillering Later applications or amounts higher than required for yield will increase grain protein 26

27 Estimating Irrigated Hard Wheat N Needs Meeting N requirements for yield and protein are two different objectives Most of the N used by wheat is taken up before flowering and later moved to the developing kernel during grain fill 27

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29 Estimating Irrigated Hard Wheat N Needs Meeting N requirements for yield and protein are two different objectives Most of the N used by wheat is taken up before flowering and later moved to the developing kernel during grain fill Stressing wheat during late grain fill and sacrificing yield should not be necessary to produce hard wheat with acceptable protein 29

30 Irrigation Management is KEY! 30

31 Estimating Irrigated Hard Wheat N Needs About pounds of nitrogen should be available for each bushel of attainable yield Split applications recommended. 60% preplant 20% tillering 20% heading to 2 wks after flowering Later applications or amounts higher than required for yield will increase grain protein Most efficient use will be when N applications occur near time needed by crop 31

32 Estimating Irrigated Hard Wheat N Needs Applying all the fertilizer N required in irrigated situations, for both maximum yield and acceptable protein, during vegetative growth can cause excessive vegetative growth and reduce yield. The protein increase from late N depends on the N rate and the plant N content. Protein may not increase much if flag leaf N concentrations at heading exceed 4.2 to 4.3 %. Consider flag leaf testing. 32

33 Estimating Irrigated Hard Wheat N Needs Applying all the fertilizer N required in irrigated situations, for both maximum yield and acceptable protein, during vegetative growth can cause excessive vegetative growth and reduce yield. The protein increase from late N depends on the N rate and the plant N content. The protein increase from late N is little affected by N sources, wheat variety or planting dates. Late N induced protein increases in most irrigated field trials have led to improved baking quality. 33

34 Flour Protein as Influenced by Topdress Timing and Rate Flour Protein (%) Tiller Boot Flower Plant Growth Stage at N Topdress Application and Rate/Acre The amount or degree of response also depends upon the variety!! 34

35 Flour Protein for Variety and N Rate Flour Protein (%) Alturas Jubilee WPB936 Iona Jefferson N Rate (lbs/ac) at N Topdress Application 35

36 Other Fertilizer Requirements lbs KCL prevents physiological leaf spot, especially with durum wheat following a root crop (20 lbs KCL) 1 5 lb SO4 (not elemental S) per 10 lb N 36

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