In-Season Estimation of Wheat Response to Nitrogen Using Normalized Difference Vegetation Index

Abstract Applying fertilizer nitrogen (N) only when a crop response is predicted may enhance use efficiency and profitability while protecting the environment. The index at harvest (RI-harvest, ratio of maximum grain yield that plot in question) indicates actual to applied N, although it calculated after harvest. objective this study was predict RI-harvest wheat using normalized difference vegetation (NDVI) (RI-NDVI, defined as NDVI an N-sufficient field captured Feekes 6 stage. Field experiments were carried out across seven site-years (2017/18 2020/21) on wheat. In first three seasons, relationships between RI-NDVI established by applying range N levels (0–320 kg ha − 1 ), whereas fourth season used for validation. results indicated could explain 79% variation linear relationship: = 7.077 × – 6.4885. This model satisfactorly validated independent data set which doses before growth Validation also dose corresponding RI-harvest. comparison general recommendation, application appropriate prescriptive along with based resulted 11% increase recovery efficiency. It suggests estimation in-season viable method identifying fields are likely respond additional N.