Using in-situ measurements to evaluate the new RapidEye™ satellite series for prediction of wheat nitrogen status

This study assessed whether vegetation indices derived from broadband RapidEye (TM) data containing the red edge region (690-730 nm) equal those computed from narrow band data in predicting nitrogen (N) status of spring wheat ( Triticum aestivum L.). Various single and combined indices were computed from in-situ spectroradiometer data and simulated RapidEye (TM) data. A new, combined index derived from the Modified Chlorophyll Absorption Ratio Index (MCARI) and the second Modified Triangular Vegetation Index (MTVI2) in ratio obtained the best regression relationships with chlorophyll meter values (Minolta Soil Plant Analysis Development (SPAD) 502 chlorophyll meter) and flag leaf N. For SPAD, r(2) values ranged from 0.45 to 0.69 ( p < 0.01) for narrow bands and from 0.35 and 0.77 ( p < 0.01) for broad bands. For leaf N, r(2) values ranged from 0.41 to 0.68 ( p < 0.01) for narrow bands and 0.37 to 0.56 (p < 0.01) for broad bands. These results are sufficiently promising to suggest that MCARI/ MTVI2 employing broadband RapidEye (TM) data is useful for predicting wheat N status.