Split N Application for Corn and Wheat: Where, When, How and What to Expect DAVE MENGEL SOIL FERTILITY A ND CROP PRODUCTION DEPARTMENT OF AGRONOMY KANSAS STATE UNIVERSITY
Some Important Facts About Kansas Crops and Climate Weather and climate is variable across the state. Rainfall decreases 2 inches annually, every 50 miles you go W Rainfall is highest in late spring and summer, lowest in winter. It is hot, and potential ET is greater than precip We grow hard red and white winter wheat Too hot for spring wheat Corn, grain sorghum and soybeans Most crops are grown rainfed or dryland Only 2-3 million acres (of 22 million) irrigated That number is decreasing
Precipitation (in) 6 5 4 3 2 1 19 inch total Colby, KS Precipitation (in) 6 5 4 3 2 1 27 inch total Hutchinson, KS 0 J F M A M J J A S O N D 0 J F M A M J J A S O N D Precipitation (in) 6 5 4 3 2 1 32 inch total Manhattan, KS Precipitation (in) 6 5 4 3 2 1 35 inch total Powhattan, KS 0 J F M A M J J A S O N D 0 J F M A M J J A S O N D
ET:Precip 2.9 2.45 2.00 1.5 Colby Powhattan Manhattan Hutch
General KSU N Recommendation for Wheat Nrec = [Yld x 2.4*] %SOM PCA PNST H 2 O Manure Tillage - Grazing Previous Yield Goal Crop 30 50 70 %SOM = % Soil OM x 10 = 20 PCA = Previous Crop Adjustment Corn 22 70 118 Corn = 0, sorghum = -30 Wheat 22 70 118 Wheat = 0, sunflower = -30 Sorghum 52 100 148 soybean = 0, fair alfalfa =+20 Sunflower 52 100 148 Fallow = +20** Soybean 22 70 118 PNST = 24 in. N Soil Test = 30 Alfalfa 2 50 98 H 2 O = ppm N x 0.226/inch Manure = 0 No-till = - 20 Grazing = - 40/100 lbs gain *2.4 is the estimated amount of N required to supply the whole plant, roots, straw and grain, adjusted for NUE (50%).
Wheat Yield with No N Fertilizer
Split N Applications on Wheat
Growth and Development of Winter Wheat Image from VTU Potential Head Size Actual Seed/Head Seed Size Number Of Heads
Common N Application Systems Used In the Western half of the state, common to apply all N preplant as ammonia, starting in August (plant in September) In the Eastern half of the state, most of the wheat is seeded following soybeans, with very little N applied, <10 pounds N, Some is topdressed in winter when herbicide is applied. Some is topdressed after it first greens up When wheat follows sorghum or sunflowers, N is added in the fall Some growers are delaying the topdressing until Feekes 5 to 7. In this case they apply ¼ to ½ the total intended N at planting Some are using crop sensors to guide N rates Very few are beginning to add additional N late, Feekes 9, to enhance protein levels.
Advantages of Different Systems Late summer or fall application. Done on fallow or wheat stubble Utilizes lowest cost fertilizer. Convenient Late winter single application system. Do under good soil and weather conditions Save application costs and trips Post green-up single application system Feekes 4/5 Can consider winter survival and later moisture levels Split application system: Fall/Spring Feekes 6/7 Can consider N loss potential or Mineralization potential In Kansas mineralization potential is a key. Soil moisture dramatically influences N and S mineralization. Fits well with sensor guidance
Sensor Guided N Rec s
Some Available Sensors
Sensors Mounted on Self Propelled Sprayer Streamer Bars Sensors Feekes 4
Reflectance (%) 0.5 Plant Reflectance Visible Near Infrared 0.25 Indicator of Available Chlorophyl Measure of living plant cell s ability to reflect infrared light 0.00 Photosynthetic Potential 450500 550 600 650 700 750 800 850 900 9501000 1050 Wavelength (nm)
Winter Wheat, Feekes 4 Manhattan, KS Red NDVI = 0.20 Pittsburg, KS Red NDVI = 0.87
Winter Wheat, Feekes 9 Manhattan, KS Red NDVI = 0.65 Yield = 60 bu/acre Pittsburg, KS Red NDVI = 0.87 Yield = 60 bu/acre
Winter Wheat Yield Potential Yield (bu/ac) 120 100 80 60 40 Feekes 4 Very low biomass: Stable, low to moderate Yield Hard to Capitalize on favorable years Excess biomass: Lodging, Disease, Water Stress Sign of high N in soil 20 0 y = -764.7x 3 + 917.94x 2-213.36x + 33.644 R² = 0.58624 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Red NDVI
KSU Single Application Algorithm Single Application Sensor Based N Rate Calculator for Winter Wheat Feekes 4-5 Inputs Yield Potential for this field or area, bushels/acre 60 Average RED NDVI Value from the Reference Strip Area 0.550 Average RED NDVI Value from the Bulk Field or Target Area 0.440 Normal Nitrogen Use Efficiency for this area (see examples) 60% Outputs Current Yield Potential of Reference Strip bushels/acre 82 Response Index (Reference NDVI/Field or Target NDVI) 1.38 Yield Potential Without Additional N Fertilization, bushels/acre 29 Yield Potential with Additional N Fertilization, bushels/acre 60 lbs N per bushel Adjusted for Field NUE 1.82 Sensor Based N Recommendation, adjusted for NUE, pounds N/acre 56
Total N Applied (lbs N/ac) and Yield (bu/ac) Comparison of Sensor to Soil Test N Rates 100 Yield Goal N Rec. vs Feekes 4 Sensor N Management 90 80 70 60 50 40 30 20 10 0 Locations and Years Yield Goal N Rec. Sensor Yield
A Multiple Topdress Option Apply more N at planting, 30-40 pounds, or topdress with a low rate of N in late winter. Make an initial topdress if needed at Feekes 4 Since a second topdressing is planned, rec s are more conservative Make a 2nd topdress at late Feekes 6/early Feekes 7. Advantages: Can determine how much N has been mineralized Can correct for late N loss Disadvantages: Some risk of not getting N on Some risk of applied N not moving into root zone Added cost of additional trip Could apply more N in the fall and only topdress at F6/7
KSU Multiple Application Algorithm Intensive Multiple Application N Rate Calculator for Winter Wheat Management Inputs Current Crop Growth Stage (Feekes Stage 4, 5, 6, 7, 8, or 9) 4 Yield Potential for this field or area, bushels/acre 60 Normal Nitrogen Use Efficiency for this area (see examples) 50% Average RED NDVI Value from the Reference Strip Area 0.630 Average RED NDVI Value from the Bulk Field or Target Area 0.510 Outputs Current Yield Potential of Reference Strip bushels/acre 62 Response Index (Reference NDVI/Field or Target NDVI) 1.24 Yield Potential Without Additional N Fertilization, bushels/acre 48 Yield Potential with Additional N Fertilization, bushels/acre 60 Sensor Based N Recommendation, adjusted for NUE, lbs. N/acre 43
2015 On Farm Multiple Topdress Results Tmt McPherson Ellis Smith Clay Cheyenne ---------------- ------------- Bu/acre ------------- ------------- No N 65 70 42 52 51 25 68 73 44 58 52 50 71 68 46 61 50 125 71 71 41 56 51 ST N 67 (23) 63 (43) 43 (42) 59 (87) 49 (70) Sensor FK4 Sensor FK4 & 7 Rec no ST (N rec) 67 (36) 67 (21) 44 (61) 59 ( 80) 52 (57) 70 (17) 72 (40) 40 (36) 62 (47) 53 (40) (60 bu YG) 94 (50 bu YG) 70 (50 bu YG) 70 (60 bu YG) 94 (50 bu YG) 70
Feekes 8-9 Application Timing Feekes 8 (Zadoks 37) Flag leaf visible in whorl. Feekes 9 (Zadoks 39) Flag leaf fully emerged with ligule visible. Feekes 8 Feekes 9 Image from Growth stages of Wheat TAMU publication SCS- 1999-16, by Travis Miller.
Feekes 8-9 Application Timing Significance: Can t fully recover yield loss from significant N deficiency at this stage. The damage has been done. Can increase grain N/protein.
Increasing Grain N and Protein at Feekes 9 2011 Crop Year All plots received 30 pounds N at seeding N added Feekes 9 Randolph Yield Randolph Protein Rossville Yield Rossville Protein Scandia Yield 0 39 12.2 52 12.2 20 13.9 25 38 11.9 58 12.6 23 15.3 50 40 12.1 55 13.1 23 16.3 Scandia Protein N added Feekes 9 Gypsum Yield Gypsum Protein N Farm Yield 0 34 13.6 60 12.7 30 46 13.6 64 13.2 60 42 15.3 66 14.3 90 38 16.3 65 15.6 N Farm Protein 2012 Crop Year
Kansas Corn Production Timeline March April April May-June July August September Preplant Fertilizer Planting Vegetative Growth Reproductive Growth Maturity
Relationship Between Total N Uptake and Grain Yield Grain Yield (bu/ac) 0 50 100 150 200 250 y = 8.1587+1.5868x 0.0025x 2 R 2 = 0.7274 0 50 100 150 200 250 Total N Uptake (lb/ac) Asebedo and Mengel, 2014
Right Rate: KSU N Rec Equation for Corn Nrec = [Yld x 1.6*] %SOM PCA PNST H 2 O Manure Where: %SOM = Percent Soil OM x 20; default = 40 PCA = Previous Crop Adjustment Corn = 0, sorghum = 0 Wheat = 0, sunflower = 0 Soybean = 40, Good alfalfa = 120 Fallow = 20 Poor alfalfa = 50 PNST = 24 in. Profile N Soil Test; default = 30 H 2 O = Irrigation Water N = 0 Manure = 0 *1.6 is the estimated amount of fertilizer N needed to produce 1 bushel of grain yield, adjusted for normal NUE of 50%.
Corn Yield as a result of ST N only 250 200 Yield 150 100 50 0 y = -0.0154x 2 + 3.6529x - 24.184 R² = 0.57763 0 20 40 60 80 100 120 140 160 Nitrate and Starter
Impact of NUE NUE is defined as the percent of the applied fertilizer N which is taken up by the crop. World-wide, NUE is about 35% In the US, it is about 45% In Kansas we assume 50% for making N recommendations We routinely measure NUE of 30 to 70% in corn and wheat in Kansas
Importance of NUE on N Rate Example: Fert Rec = (150 bu x 1.6) SOM- PNST- Crop Adjust 130 = 240-40 - 30 40 (soybeans) @ 50% NUE, increases Nup by 65 lbs 130 x 0.5 = 65 Fert rec @ 40% NUE = 65 lb Nup increase/0.4 = 163 lb Fert rec @ 60% NUE = 65 lb Nup increase/0.6 = 108 lb
Right N Timing Timing is the traditional tool to address N loss due to Leaching Denitrification Alternatives can include: nitrification inhibitors controlled release products (ESN)
V-6 V-12
Response to Time of Application, Controlled Release Fertilizers and Nitrification Inhibitors in No-till Corn, Treatment Yield, bu/a No N 120 February urea on surface 159 February ESN on surface 179 Urea V-2 191 Urea V-2+ Agrotain 201 Urea/ESN blend 201 Weber and Mengel, 2009
When N is Applied to Corn Timing Urea ESN Yield, bu/acre Yield, bu/acre Late Winter 207 221 2 leaf 206 218 8 leaf 222 223 No N applied, 167 Asebedo and Mengel, 2011, NCKS Experiment Field, Scandia KS C/S rotation, limited irrigation, 100 lbs actual N
Late Sidedress N Application on Corn Treatment N Rate lb/ac Grain Yield bu/ac Pre-plant N 60 133 e Pre-plant N + 30 at V-8 90 158 d Pre-plant N + 60 at V-8 120 173 c Pre-plant N + 90 at V-8 150 185 bc Pre-plant N + 30 at V-16 90 166 cd Pre-plant N + 60 at V-16 120 192 b Pre-plant N + 90 at V-16 150 206 a Tucker and Mengel, KSU Agronomy North Farm, 2009
Effects of Nitrogen application timing on corn grain yield, 2014, irrigated, Scandia, KS Starter Early Total N Treatment N N V-4 N V-10 N R1 N Applied 2014 Yield 1 20 0 0 0 0 20 160 h 3 20 120 0 0 0 140 211 ef 4 20 180 0 0 0 200 216 de 6 20 0 120 0 0 140 229 abc 7 20 0 180 0 0 200 230 ab 9 20 0 0 120 0 140 216 de 10 20 0 0 180 0 200 229 abc 13 20 0 60 0 60 140 218 bcd 14 20 0 60 0 120 200 223 abcd 16, Agron 20 0 60 0 30 110 210 ef 17 U/ESN 20 120 0 0 0 140 225 abcd
Precipitaiton (inch) 3 2014 Scandia Rainfall and Irrigation 2.5 2 1.5 1 0.5 0 Date
Effects of Nitrogen application timing on corn grain yield, 2015, irrigated, Scandia, KS Starter Early Total N Treatment N N V-4 N V-10 N R1 N Applied 2015 Yield 1 20 0 0 0 0 20 152 d 3 20 120 0 0 0 140 201 abc 4 20 180 0 0 0 200 217 a 6 20 0 120 0 0 140 216 a 7 20 0 180 0 0 200 208 ab 9 20 0 0 120 0 140 202 abc 10 20 0 0 180 0 200 205 abc 13 20 0 60 0 60 140 205 abc 14 20 0 60 0 120 200 212 a 16, Agron 20 0 60 0 30 110 192 bc 17 U/ESN 20 120 0 0 0 140 202 abc
Precipitaiton (inch) 3 2015 Scandia Rainfall 2.5 2 1.5 1 0.5 0 Date
Effects of Nitrogen application timing on corn grain yield, 2014, irrigated, Rossville, KS Starter Early Total N Treatment N N V-4 N V-10 N R1 N Applied 2014 Yield 1 20 0 0 0 0 20 97 e 3 20 120 0 0 0 140 151 dc 4 20 180 0 0 0 200 175 abc 6 20 0 120 0 0 140 168 bc 7 20 0 180 0 0 200 187 ab 9 20 0 0 120 0 140 172 ab 10 20 0 0 180 0 200 188 ab 13 20 0 60 0 60 140 183 ab 14 20 0 60 0 120 200 192 ab 16, Agron 20 0 60 0 45 125 174 abc 17 U/ESN 20 120 0 0 0 140 186 ab
Precipitaiton (inch) 3 2014 Rossville Rainfall and Irrigation 2.5 2 1.5 1 0.5 0 Date
Effects of Nitrogen application timing on corn grain yield, 2015, irrigated, Rossville, KS Starter Early Total N Treatment N N V-4 N V-10 N R1 N Applied 2015 Yield 1 20 0 0 0 0 20 72 h 3 20 120 0 0 0 140 151 cdef 4 20 180 0 0 0 200 153 cde 6 20 0 120 0 0 140 182 ab 7 20 0 180 0 0 200 186 a 9 20 0 0 120 0 140 147 def 10 20 0 0 180 0 200 127 efg 13 20 0 60 0 60 140 186 abcd 14 20 0 60 0 120 200 156bcd 16, Agron 20 0 60 0 15 95 127 efg 17 U/ESN 20 120 0 0 0 140 178 abc
Precipitaiton (inch) 2015 Rossville Rainfall and Irrigation 3 2.5 2 1.5 1 0.5 0 Date
Sensors Can Be Used To Adjust Rate On Corn Or Milo also
Rossville Results 2007-2009 Treatment Mean N Rate over three years, lb/a Mean Grain Yield over Three years bu/ac Starter Only 20 102 c 120 pre 120 214 b 160 pre 160 223 ab 200 pre 200 231 a 120 split 120 209 b 160 split 160 223 ab 200 split 200 224 ab 120 + GS 145 228 ab 120 + CC 153 226 ab 120 + Spad 141 214 b Tucker and Mengel, Kansas River Valley Exp Field
What Could Future Systems Look Like Soil Test to assess residual N available before planting. Assess loss potential of your site to define specific practices to use. Apply 60 to 80% of normal needs for that site with some combination of Starter or at planting Preplant or early sidedress to ensure adequate N for ear size Late sidedress V-8 to V-10 Reassess need at late vegetative growth stages using on-the-go sensing on applicator to top off the system. In high loss irrigated system might include a late application through the pivot. Use a fall-winter trap crop to collect residual and late mineralized N from escaping to ground or surface waters.
What Could Future Systems Look Like Total applications could vary from 1 or 2 in low loss soils and environments to as many as 4 or 5 in high loss environments. More N will be placed below the residue Controlled release fertilizers and inhibitors could be used as alternatives to placement and timing. Care will be needed to ensure the product addresses the real concern at that particular site NUE by recovery could be as high as 60-70% N Rates should be adjusted down as NUE goes up, or losses will increase.
Questions? dmengel@ksu.edu
Microbial Activity and Mineralization Microbial activity follows plant growth In very mild winters, low levels of mineralization can occur from low C:N crops (soybeans and legumes) Generally when a drought breaks and the soil wets up, we get a flush of nutrients mineralized from the soil, much more than we normally would expect.