Study On Establishment Of Cotton Nitrogen Nutrition Spectrum Estimation Model And Diagnosis System

The field exper iment used the Geeenseeker active remote sensing spectrometer to obtain canopy NDVI value and nutrition diagnosis parameters, we analyzed canopy NDVI value change rule and related nutrition diagnosis index parameter change rule under the condition of different w ater and nitrogen combination in each growth period, then analyzed the relationship bettween canopy NDVI value and the related indicators. Finally we screen out the relevant models for predicting the nutrition diagnos is at different period of cotton, then through personal intelligence decision system technology and computer technology together, set up cotton nutrition diagnosis decision support system. The main results were as follows:1. Effects of different water and nitrogen treatments on the growth of cottonThe influence on the leaf area index, dry matt er accumulation, production under the condition of different water and nitrogen: the leaf area index increased with the increase of N application rate increased, it increased slowlly in the early stage and the growth difference was not significant, then rised fast in mid-season peak with obvious difference, late difference decreases gradually. Under the condition of same water and different nitrogen treatment, dry matter increased with the increase of N application rate under the low water treatment(W1) and conventional treatment(W2). Dry matter increased with the increase of N application rate reached peak and the gradually reduced under the high water treatment(W3); when the diminishing marginal product is 0, the total yield reached the highest value. Under the treatment of no, low nitrogen(N0, N1), the yield increased with the increase of irrigation amount. In the middle and high(N2, N3) treatment, the yield increased first and then decreased. Under different water and nitrogen treatments, the chlorophyll content of cotton in different growth stages was significantly different than that in the early stage of cotton growth. Chlorophyll content under the interaction of water and nitrogen, the diff erence between the early stage is small, 80-105 d after the emergence of a larger difference, the latter gradually decreased. Under the same water treatment condition, the nitrogen content of the 4 nitrogen treatments showed extremely significant difference at different growth stages. Under the interaction of water and nitrogen, the nitrogen content in 70-105 d leaves of cotton after seedling emergence was extremely significant difference, and the difference was decreased at the later stage. 2. Variation characteristics of NDVI value in cotton canopy and its correlation with nutritional parametersCanopy NDVI value showed "low- high- low" trend. In W1,W3 irrigation treatment, 4 nitrogen treatment in cotton seedling after 70, 105 and 125 d were signif icantly different, other differences were not obvious. Conventional irr igation W2(in addition to 95 d after the emergence of cotton), the level of 4 nitrogen fertilization treatment reached very significant difference. Under the interaction of w ater and nitrogen, the NDVI values of 80, 105 and 140 d were significantly different after the emergence of cotton.Correlation analysis of canopy NDVI value and nutrition diagnosis parameter: canopy NDVI value and leaf area index, dry matter accumulation, leaf chlorophyll content, leaf nitrogen content present a linear relationship and present a quadratic parabola function relation with production. Through the model validation we found that: canopy NDVI value can predict well the cotton dry matter and leaf area index after 125 d of emergence; The canopy NDVI value of the 105 d after emergence to obtain estimates of cotton production;Using canopy NDVI value after 95 d, 105 d,125d of cotton emergence to estimate leaf total nitrogen content; Using canopy NDVI value 95 d,105d,125 d after cotton emergence to estimate leaf chlorophyll content. 3.Establishment of cotton nutrition diagnosis system based on Android system platformThrough the integrated model of professional and technical, according to the obtained optimal recommendation model, build a system based on the Android platform, to build based estimation of cotton dry matter accumulation, leaf area index, leaf chlorophyll content, leaf nitrogen content, yield of cotton nutrition diagnosis system based on c anopy NDVI value.