Split N Application for Corn and Wheat: Where, When, How and What to Expect

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1 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

2 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

3 Precipitation (in) inch total Colby, KS Precipitation (in) 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) inch total Manhattan, KS Precipitation (in) 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

4 ET:Precip Colby Powhattan Manhattan Hutch

5 General KSU N Recommendation for Wheat Nrec = [Yld x 2.4*] %SOM PCA PNST H 2 O Manure Tillage - Grazing Previous Yield Goal Crop %SOM = % Soil OM x 10 = 20 PCA = Previous Crop Adjustment Corn Corn = 0, sorghum = -30 Wheat Wheat = 0, sunflower = -30 Sorghum soybean = 0, fair alfalfa =+20 Sunflower Fallow = +20** Soybean PNST = 24 in. N Soil Test = 30 Alfalfa 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%).

6 Wheat Yield with No N Fertilizer

7 Split N Applications on Wheat

8 Growth and Development of Winter Wheat Image from VTU Potential Head Size Actual Seed/Head Seed Size Number Of Heads

9 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.

10 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

11 Sensor Guided N Rec s

12 Some Available Sensors

13 Sensors Mounted on Self Propelled Sprayer Streamer Bars Sensors Feekes 4

14 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 Wavelength (nm)

15 Winter Wheat, Feekes 4 Manhattan, KS Red NDVI = 0.20 Pittsburg, KS Red NDVI = 0.87

16 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

17 Winter Wheat Yield Potential Yield (bu/ac) 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 = x x x R² = Red NDVI

18 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 Average RED NDVI Value from the Bulk Field or Target Area 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

19 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 Locations and Years Yield Goal N Rec. Sensor Yield

20 A Multiple Topdress Option Apply more N at planting, 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

630 Average RED NDVI Value from the Bulk Field or Target Area 0.

21 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 Average RED NDVI Value from the Bulk Field or Target Area 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

22 2015 On Farm Multiple Topdress Results Tmt McPherson Ellis Smith Clay Cheyenne Bu/acre No N 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

23 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 , by Travis Miller.

24 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.

25 Increasing Grain N and Protein at Feekes Crop Year All plots received 30 pounds N at seeding N added Feekes 9 Randolph Yield Randolph Protein Rossville Yield Rossville Protein Scandia Yield Scandia Protein N added Feekes 9 Gypsum Yield Gypsum Protein N Farm Yield N Farm Protein 2012 Crop Year

27 Kansas Corn Production Timeline March April April May-June July August September Preplant Fertilizer Planting Vegetative Growth Reproductive Growth Maturity

28 Relationship Between Total N Uptake and Grain Yield Grain Yield (bu/ac) y = x x 2 R 2 = Total N Uptake (lb/ac) Asebedo and Mengel, 2014

29 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%.

30 Corn Yield as a result of ST N only Yield y = x x R² = Nitrate and Starter

31 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

32 Importance of NUE on N Rate Example: Fert Rec = (150 bu x 1.6) SOM- PNST- Crop Adjust 130 = % NUE, increases Nup by 65 lbs 130 x 0.5 = 65 Fert 40% NUE = 65 lb Nup increase/0.4 = 163 lb Fert 60% NUE = 65 lb Nup increase/0.6 = 108 lb

33 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)

34 V-6 V-12

35 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 Urea V-2+ Agrotain 201 Urea/ESN blend 201 Weber and Mengel, 2009

36 When N is Applied to Corn Timing Urea ESN Yield, bu/acre Yield, bu/acre Late Winter leaf leaf No N applied, 167 Asebedo and Mengel, 2011, NCKS Experiment Field, Scandia KS C/S rotation, limited irrigation, 100 lbs actual N

37 Late Sidedress N Application on Corn Treatment N Rate lb/ac Grain Yield bu/ac Pre-plant N e Pre-plant N + 30 at V d Pre-plant N + 60 at V c Pre-plant N + 90 at V bc Pre-plant N + 30 at V cd Pre-plant N + 60 at V b Pre-plant N + 90 at V a Tucker and Mengel, KSU Agronomy North Farm, 2009

38 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 h ef de abc ab de abc bcd abcd 16, Agron ef 17 U/ESN abcd

39 Precipitaiton (inch) Scandia Rainfall and Irrigation Date

40 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 d abc a a ab abc abc abc a 16, Agron bc 17 U/ESN abc

41 Precipitaiton (inch) Scandia Rainfall Date

42 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 e dc abc bc ab ab ab ab ab 16, Agron abc 17 U/ESN ab

43 Precipitaiton (inch) Rossville Rainfall and Irrigation Date

44 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 h cdef cde ab a def efg abcd bcd 16, Agron efg 17 U/ESN abc

45 Precipitaiton (inch) 2015 Rossville Rainfall and Irrigation Date

47 Sensors Can Be Used To Adjust Rate On Corn Or Milo also

48 Rossville Results Treatment Mean N Rate over three years, lb/a Mean Grain Yield over Three years bu/ac Starter Only c 120 pre b 160 pre ab 200 pre a 120 split b 160 split ab 200 split ab GS ab CC ab Spad b Tucker and Mengel, Kansas River Valley Exp Field

49 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.

50 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.

51 Questions?

52 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.

Using N Timing to Enhance Yield and Nitrogen Use Efficiency in High Yielding Dryland and Irrigated Corn

Using N Timing to Enhance Yield and Nitrogen Use Efficiency in High Yielding Dryland and Irrigated Corn A.R. Asebedo and D. B. Mengel Kansas State University, Manhattan, KS Abstract Nitrogen (N) management