Estimating Nitrogen Content based on Hyperspectrum of the Apple Florescence Canopy

The paper is to establish a kind of fast, nondestructive method of estimating nitrogen content for the apple canopy and to provide the prior knowledge for large area of fruit trees nutrition diagnosis with remote sensing technique . Utilizing detection hyperspectral data of the apple florescence canopy and nitrogen content data in Qixia county of experimental orchards in 2008. The correlation analysis of hyperspectral reflectance and its eleven transforms with nitrogen content is proceed, the bigger correlation coefficient as independent variable, nitrogen content as dependent variable. The estimating model of nitrogen content is established by multiple stepwise regression analysis. The model is inspected. The results shown that the correlation is less to the original spectral reflectance (R) and its reciprocal(1/R), logarithmic (lgR), square root (R) and the content of nitrogen , but it is enhanced obvious in their first derivative, second order derivatives and nitrogen content. Estimating model of nitrogen content is built. The best model for the independent variable (lgR). It is Y = 31.6212732.6096 X832-3307.728 X849 + 2901.7231 X922-3172.324 X1019 after optimization. Upon testing, the best model of the estimated value and measured value, which the correlation factor of fitting equation R is the largest, 0.7325, the total root mean square difference RMSE is minimum, 2.3802, the relative error RE % is minimum, 8.1% and estimation accuracy is reached 91.9%. It shown that this model used for apple florescence canopy of nitrogen content in the estimation is very stability and universality.