[Estimated nitrogen nutrition index based on the hyperspectral for wheat of drip irrigation under mulch]

The accurate wheat management needs a reasonable nitrogen application, and it is one of the key measures for real-time and quantitatively monitoring of nitrogen status to gain the higher yield of wheat. In the present study, two field experiments were conducted with different nitrogen stress and wheat cultivars, the relationship was analyzed between spectral parameters and the partial factor productivity from applied N (PFPn), and the estimating model was established for PFP, in the growth stages of wheat. The result indicated that there was a highly significant correlation between the PFP, and GreenNDVI at jointing, the correlation coefficient (r) was 0.6404, the estimating model of PFPn was established, and the root mean square errors (RMSE) was 0.4597. The result indicated that the PFPn can be effectively estimated by using spectral parameters.