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Replacing SOIL TESTING

Replacing SOIL TESTING. In-Season Soil Testing. Use of an in-season soil test for N availability in corn PSNT (0-30cm), Magdoff et al. (1984).

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Replacing SOIL TESTING

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  1. Replacing SOIL TESTING

  2. In-Season Soil Testing • Use of an in-season soil test for N availability in corn PSNT (0-30cm), Magdoff et al. (1984). • Separating nitrate test calibration data based on yield potential of soils may improve PSNT and PPNT for making N recommendations in corn, when NO3 test values are in the N responsive region (Bundy and Andraski, 1995) • No soil test accurately predicted either relative grain yield or N-supplying capacity (Fox et al., 1993). • Relative grain yield vs PSNT relationship was better with NO3 and NH4 than with NO3 alone (Meisinger et al., 1992)

  3. Sufficiency • Levels of available nutrients range in a group of soils from insufficient to sufficient for optimum plant growth • Amounts of nutrients removed by suitable extractants will be inversely proportional to yield increases from added nutrients • Calibrations have been made for changing the levels of available nutrients in the soil by adding fertilizer

  4. Mobile Nutrient Yield Goal (Risk assessment of the environment) • Immobile Nutrient Sufficiency Level (Independent of Environment, % of Maximum yield)

  5. Bray’s Mobility Concept Mobile Nutrients Immobile Nutrients • Depends on Growth Stage • Indicators • Biomass • Color • Concentration • Independent of Growth Stage • Indicators • Biomass • Color Sensor View Sensor NO3- H2PO4- HPO4= Soil Test Root System Sorption Zone Root Surface Sorption Zone • Response depends on reservoir • Indicator of total available • Dependent on environment • Response does not depend on reservoir • Indicator of availability • Independent of environment

  6. Present N Recommendation • Fertilizer N = yield goal (bu/ac)*2 - soil test NO3-N Future N Recommendation • Estimated topdress N = f (yield potential and total N uptake, estimated using indirect measures)

  7. Could we establish a sufficiency level (by growth stage, variety, etc) at Feekes 5? • NDVI N Uptake Suff. N Rec • 0.3 35 40 Yld goal*1.5 • 0.5 45 60 Yld goal*1.0 • 0.7 55 80 Yld goal*0.7 • 0.9 65 100 Yld goal*0.2

  8. SPAD 501, 502 (430, 750) Absorption of Visible Light by Photopigments Sunlight reaching earth Phycoerythrin Chlorophyll b Phycocyanin Absorption B-Carotene Chlorophyll a 300 400 500 600 700 800 Wavelength, nm CAUSE/EFFECT

  9. Soil testing vs. Sensor based systems for developing nutrient recommendations Soil Testing Sensor Based Analyses Detection Plant available Plant status Sample collection >20 hectares 1m2 Sampling soil, destructive plant, non-destructive Method Extraction & chemical Spectral radiance, analyses wavelength specific Analytical parameter Nutrient element Spectral radiance Interpretation Calibration with yield Calibration with yield Fertilizer Rec. Procedure specific Wavelength/index specific Interfering Factors Affecting Fertilizer Recommendation Number of samples (reliability) Subsoil N availability - - Weeds - Clouds - Time of day (sun angle) - Variety - Stage of growth (% cover) - Living vs. dead plant tissue Field element size Field element size Calibration curve Calibration curve

  10. Evolution of a soil test Extraction Correlation Calibration On-farm Suff. Procedure with field of rates at validation Index response a given soil test level Wavelength Correlation Calibration On-farm Suff. /Index/band with field of rates at validation Index response a given ___ env. spec. Evolution of a spectral test

  11. NDVI Strengths • Sensitive to canopy cover in sparse canopies • Excellent predictor of total N uptake (vegetative stages) • Amount of variability in N uptake explained by NDVI increases with advancing growth stage (% coverage) • Good predictor of N uptake following freeze damage • Prairie biomass (fuel load) • Foliage surface area (pine) • N fertilization need in maize (pre-flowering) 1996 Agron. J. • Area affected by forest fires Weaknesses • Not sensitive to canopy cover in dense canopies (2D not 3D) • Not a good predictor of N concentration

  12. Indices • Landsat Satellite Thermic Mapper (TM) mid and near infrared indices • plant density, drought, tillage • SR (simple ratio)=NIR/red • NDVI (normalized difference vegetation index) = (NIR-red)/(NIR+red) • biomass, forage N uptake, water stress, leaf area index • G-NDVI= (NIR-green)/(NIR+green) • STVI (stress related vegetation index) • MPDI (microwave polarization difference index) • NPCI (normalized pigment chlorophyll ratio index) =(R680-R430)/(R680+R430)

  13. Indices • WBI (water band index) = R970-R900 • PRI (physiological reflectance index) • = (R550-R530)/(R550+R530) ‘narrow waveband spectral measurements’ (sunflower) • chlorophyll, net CO2 uptake, water potential, light use efficiency

  14. What should we learn from soil testing? • Process of elimination • Justus von Leibig (1803-1873) • Leibig’s Law of the Minimum; nutrient present in the least relative amount is the limiting nutrient for plant growth • all other nutrients present in excess until the deficient or limiting nutrient was in adequate supply • Father of ‘soil testing’ Liebig Hyperlink

  15. Fact Sheet 2225 • Crop • small grains, sorghum, corn, cotton, cool season grasses, weeping lovegrass, bluestem, bermudagrass, forage sorghum or corn silage, small grains for grazing, legumes in pasture, native meadows, alfalfa, peanuts, soybeans, mungbeans, cowpeas • N, P, K, S, Ca, Mg, Zn, Fe, Mn, Cu, B • pH/buffer index (lime)

  16. Could N uptake be used as an indicator of yield potential when other variables are controlling response? Should we develop technologies that treat variable ‘yield potential’ What influences NDVI? How can I use the NDVI measurement from last year, this year? Soil Testing: Method of Extraction

  17. Phosphorus • Fluoresce= reemit light energy absorbed as light but of a longer wavelength and of lower energy • Fluorescence spectrum is characteristic of the pigment, so it is possible to tell which pigment is fluorescing (which one was activated) • Low P nutrition results in increased chlorophyll fluorescence, reduced photosynthetic rate, increased starch and sucrose in leaves • If the reactions of photosynthesis are blocked (chemical, cold, etc.) fluorescence will occur in-vivo because the energy absorbed cannot be used. • x-ray fluorescence (total P in plants) • Time required to induce/measure fluorescence (1-2 min) Xanthophyll

  18. Subsoil nutrient availability • Can sensor based technologies assess subsurface nutrient availability? • Sensing with time (Stage of growth) could provide an indicator of subsurface nutrient availability T1 T2 T3 T4

  19. Short wavelength High frequency High energy Long wavelength Low frequency Low energy Yellow-green Yellow Violet Blue Green-blue Blue-green VISIBLE Color Transmitted Microwaves and short radio Violet Blue Green Yellow Orange Red Radio, FM, TV Gamma Rays Ultraviolet VISIBLE Color Absorbed Infrared X-Rays 0.01 10 380 450 495 570 590 620 750 1x106 1x1011 wavelength, nm Electronic Vibrational Rotational transitions transitions transitions

  20. Models for Interpretation of Response • Linear • Linear-plateau • Quadratic • Square root • Quadratic-plateau • Cate-Nelson

  21. YIELD POTENTIAL “TRIP DISTANCE” N FERTILIZER NEED Gallons 20 35 20 mpg 400 miles 10 mpg 350 miles YP0 = 100 bushelsYPN = 140 bushels (RI of 1.4)Grain N Uptake based on YPN of 140 bu/ac = 140 bu/ac * 56 lb/bu * 1.18%N = 92.5 lb Have 60 kg N in the plant Need = (92.5-60)/0.7 = 46.4 40 30 60 20

  22. Crop Production Travel Planning Yield Potential (YP0) Trip Distance Yield Potential with Trip Distance (adj.)added N (YPN) Forage N Uptake Amount of Gas in TankGrain N Uptake (YPN) Total Gallons Needed Fertilizer Need Total Gallons-Amt in Tank Topdress N rate range Fuel efficiency (rainfall, temp (windspeed, frost, plant stand, direction, road weed population) conditions, uphill, downhill, etc.)

  23. Interfering agronomic factors • Moisture availability (texture, water holding capacity) • Nutrient(s) deficiency(ies) and/or toxicity(ies) interactions • Crop • Variety within crop • Preplant N rate • Production system (forage vs. grain) • Tillage (background) • Weed interference • Row spacing (coverage, plant density) • Resolution to be treated (field element size) • cost of misapplication (economic vs. environment)

  24. Hennessey, Feekes 4, 5 and 7 250 200 Feekes Growth Stage 4 150 y = 286.62x - 20.226 = 0.3588 R 2 Total N Uptake, kg/ha 100 Feekes Growth Stage 5 y = 97.953x - 12.413 2 R = 0.6687 Feekes Growth Stage 7 50 y = 234.78x - 9.4074 = 0.7286 R 2 0 0 0.2 0.4 0.6 0.8 NDVI

  25. Frequency Distribution of Variable Nitrogen Rates (4, 1x42m transects) 70 60 0 50 40 Frequency 30 20 10 80 0 80 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0-10 30-40 10-20 20-30 60-70 40-50 50-60 70-80 NDVI N rate, kg/ha Max. N Rate determined by farmer

  26. RESOLUTION STUDYTreatment Structure Treatment Treatment Number of Resolution Subplots 1 0.84 m2 64 2 3.34 m2 16 3 13.38 m2 4 4 53.51 m2 1

  27. Contour map of NDVI values at Tipton, OK 01 02 03 04 01 02 03 04 05 06 07 08 01 04 01 16 15 14 13 12 11 10 09 NDVI 08 07 06 05 17 18 19 20 21 22 23 24 32 31 30 29 28 27 26 25 02 03 09 10 11 12 33 34 35 36 37 38 39 40 0.48 48 47 46 45 44 43 42 41 16 15 14 13 49 50 51 52 53 54 55 56 0.45 64 63 62 61 60 59 58 57 0.42 01 02 03 04 05 06 07 08 01 04 01 02 01 02 03 04 16 15 14 13 12 11 10 09 0.39 08 07 06 05 17 18 19 20 21 22 23 24 32 31 30 29 28 27 26 25 0.36 09 10 11 12 02 03 33 34 35 36 37 38 39 40 04 03 48 47 46 45 44 43 42 41 0.33 16 15 14 13 49 50 51 52 53 54 55 56 64 63 62 61 60 59 58 57 0.30 01 01 02 03 04 01 02 03 04 05 06 07 08 01 0.27 16 15 14 13 12 11 10 09 17 18 19 20 21 22 23 24 08 07 06 05 0.24 32 31 30 29 28 27 26 25 33 34 35 36 37 38 39 40 09 10 11 12 0.21 48 47 46 45 44 43 42 41 49 50 51 52 53 54 55 56 0.18 16 15 14 13 64 63 62 61 60 59 58 57

  28. Distribution of NDVI values, Tipton, OK 30 25 20 Frequency 15 10 5 0 0.5 0.7 0.3 0.26 0.34 0.38 0.42 0.46 0.54 0.58 0.62 0.66 0.74 0.78 NDVI

  29. Tipton, January 15, 1998, Feekes 5 Fertilizer N Rate Percent Coverage 35 55 85 NDVI 0.3 0.5 0.7

  30. Tipton, January 15, 1998, Feekes 5 Percent Coverage 35 55 85 NDVI 0.3 0.5 0.7

  31. Location: Perkins, 1997-98 Res. N Rate SD Yield SD Efficiency SD N Uptake SD m2 kg/ha kg/ha of Use** kg/ha ____ ___________ _________ ____________ ___________ 0.84 56.95 19.04 2323 162 44.25 15.65 51.53 1.88 3.34 74.17 18.43 2329 382 33.47 12.52 52.30 5.81 13.38 69.28 23.13 2473 233 38.77 13.79 54.21 4.67 53.51 73.93 25.26 2555 266 37.58 13.95 60.27 6.63 SED 13.97 127 7.28 3.22 ** Moll et al., 1982

  32. Variable rate spray nozzle Sensor assembly Sensed area (treated area)

  33. Spectral radiance (250-830 nm) collected from individual plots, NxP bermudagrass experiment, Burneyville, OK • NIR 0.25 N0 P0 N0 P60 N0 P120 0.2 N100 P0 N100 P60 N100 P120 • Red N200 P0 0.15 N200 P60 N200 P120 • Green N300 P0 Spectral radiance, % N300 P60 0.1 N300 P120 0.05 0 250 350 450 550 650 750 850 Wavelength, nm Hasil Sembiring OSU Soil Fertility

  34. 1 5 8 6 11 4 2 3 9 7 12 10 3 4 12 10 8 7 5 1 9 2 11 6 8 3 7 5 1 12 11 4 6 2 9 10 30 ft Trt N rate P rate 1 0 0 2 40 0 3 80 0 4 120 0 5 0 10 6 40 10 7 80 10 8 120 10 9 0 20 10 40 20 11 80 20 12 120 20 10 ft

  35. 50 40 30 20 10 0 0 40 80 120 Source of variation df P N w919w791 Total (r*N*P)-1 35 - - Rep 2 ns ns N Rate 3 ns ** P Rate 2 ** ns N Rate * P Rate 6 ns ns Error 22 - -

  36. 0.3 0.3 0.25 0.25 N0 P0 N300 P0 0.2 0.2 N0 P60 N300 P60 N0 P120 N300 P120 0.15 0.15 Spectral radiance, % 0.1 0.1 0.05 0.05 0 0 395 515 575 695 276 395 455 515 575 695 755 276 335 455 635 755 815 335 635 815 Wavelength, nm Hasil Sembiring OSU Soil Fertility

  37. Wavelength ID 404 414 425 - - 584 735 775 785 N 0.02 0.04 . . . - 0.01 0.01 0.01 P . . . . . 0.18 - 0.04 0.03 NP . . . . . - 0.01 0.02 0.02 3.7 60 30 0 3.65 3.6 3.55 w735/w534 3.5 3.45 3.4 3.35 3.3 0 50 100 150 200 250 300 N Rate Hasil Sembiring OSU Soil Fertility

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