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By-Plant Prediction of Corn Forage Biomass and Grain Yield at Various Growth Stages using NDVI and Plant Height. K. Freeman, B. Raun, K. Martin, R.Teal, D. Arnall, M. Stone, J. Solie . Introduction. Stone el al., 1996 found that N uptake could be predicted in winter wheat using NDVI.
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By-Plant Prediction of Corn Forage Biomass and Grain Yield at Various Growth Stages using NDVI and Plant Height K. Freeman, B. Raun, K. Martin, R.Teal, D. Arnall, M. Stone, J. Solie
Introduction • Stone el al., 1996 found that N uptake could be predicted in winter wheat using NDVI. • Varvel et al., 1997 noted that corn N status could be monitored using chlorophyll meters. • Muchado et al., 2002 stated that in dry years, plant height can explain 90% and 61% of the variation of total dry and grain yield, respectively.
Introduction • Prediction of Corn Forage Biomass • Avenue for predicting final grain yield • Estimate Corn Silage in the Field • Prediction of Corn Forage N Uptake • Prediction of Corn Grain Yield • Ability to predict corn grain yield will help to prescribe N rates mid-season • These rates can be predicted on a by-plant basis
Objective To determine the feasibility of by-plant sensor data collected at various stages of corn development for predicting corn forage biomass, N uptake, and corn grain yield.
Methods • INSEY_DFP = NDVI / Days from Planting to Sensing • INSEY_GDD = NDVI / Cumulative GDD from Planting to Sensing • GDD = (Tempmin + Tempmax /2) – 40 F • Regression analysis performed using an exponential model
Methods • A GreenSeeker Sensor was mounted on a bicycle • A shaft encoder was used to assign distance to each sensor reading • Readings were taken once per centimeter
Methods • Plant Height measurements were taken at each sensor reading and clipping • Heights were measured by extending the last collared leaf upright
Methods 1 2 3 10cm 30cm Area Calculation for Plant 2 Area = ½(10) + ½(30)* Row Spacing Then, Area = (5 cm + 15cm)* 76cm= 1520 cm2
Conclusions • NDVI was a better predictor of forage yield at early growth stages • N uptake was correlated with NDVI at early and later growth stages • The product of NDVI and Plant Height improved the ability to predict forage and N uptake
Conclusions • Final grain yield was accurately predicted at the V10 and V8 growth stages. • INSEY was slightly better than NDVI alone for predicting final grain yield. • There was no difference between INSEY_DFP and INSEY_GDD.
http://www.soiltesting.okstate.edu/SBNRC/SBNRC.php http://www.nue.okstate.edu
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By-Plant Prediction of Corn Forage N uptake at V8-V11 Growth Stage using Plant Height in 2003 & 2004
By-Plant Prediction of Corn Forage N Uptake at V8-V11 Growth Stage using NDVI*Height in 2003 & 2004
