Nitrogen Management Experiences in the Rainfed Corn Belt (Iowa)

Nitrogen Management Decisions Soil Tests Yield Goal Last Year’s Application Rate

Improving N Fertilization Field scale N responses Water-N interactions

Image process NDVI (B4 - B3) / (B4 + B3) Simple Ratio SAVI (Soil adjusted vegetation index) MSAVI (Modified Soil adjusted vegetation index) NPCI Normalized Pigment Chlorophyll ratio Index RS Index well correlated with Yield and or Chlorophyll content

Yield Correlation with RS data SAVI 3 rd flight SAVI 4 th flight

R3 SPAD means, Aug. 01, 2002

Exploratory Research Assessment of field-scale N responses Remote sensing of N variation in the field Field-scale decision processes incorporating soils, water, and N

Coon Rapids Smoothed Yields

Coon Rapids – September NDVI Field variation induced by previous management

Correlation Yields & Red/Green

Coon Rapids - Correlations Correlations prior to development of yield polygons

Coon Rapids – Red/Green Variability

Dallas South Field EMI Map Smoothed Yields Red/Green Index

Yield-Spectral Indices Correlated by yield polygons Dallas-South

Dallas South – Red/Green Variability