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Northwest University of Science and Technology (2009)

Study on Cotton Coupling Effect of Water and Nitrogen under Different Irrigation Patterns in the Minqin Oasis

Li Pei Ling

Titre : Study on Cotton Coupling Effect of Water and Nitrogen under Different Irrigation Patterns in the Minqin Oasis

Auteur : Li Pei Ling

Grade : Doctoral Dissertation 2009

Université : Northwest University of Science and Technology

Résumé partiel
In China’s western Gansu Minqin oasis areas, the shortage of water resources and low utilization of agricultural water-fertilizer are the main problems of agricultural production restrictions. In recent years, farmland in the region to improve water use efficiency of water-saving irrigation technology research and development of the crop in the region to effectively improve the water environment, and improve irrigation water use efficiency has played a significant role. But at the same time saving ways to improve crop nutrient use efficiency, especially in water-saving irrigation water and nitrogen under the conditions of the coupling effect, in recent years become a hot issue in academic research, as currently, although some research results, but an oasis in the desert The study also relatively small area. Cotton under different irrigation water and nitrogen coupling effect of the study, improve the region for effective water and nitrogen use efficiency of cotton to improve the soil environment has important theoretical and practical significance. Based on the Minqin oasis Daejeon cotton irrigation district, systems research and analysis of cotton under different irrigation water and nitrogen coupling effect, the main conclusions of the pilot study are as follows :(1) The coupling effect of water and nitrogen under different furrow irrigation patterns shows that water and nitrogen application rate increased in the three furrow irrigation patterns will help improve cotton yield, but FFI limit the effects of water and nitrogen play, AFI and CFI not significant differences in the effects of cotton yield. Cotton NUE under different furrow irrigation patterns, increased irrigation and control fertilizer application can significantly improve, the promotion of AFI exert effects of nitrogen, and limits the effect of FFI. Cotton WUE under different furrow irrigation patterns, increased nitrogen application rate and control the volume of water can enhance the promotion of WUE, compared with the CFI, AFI has promoted exert effects of water and nitrogen, FFI reduce the effects of water and nitrogen play. The coupling effect of water and nitrogen in furrow irrigation shows that AFI most can promote the coupling effect to play, and promote cotton.efficient use of water and nitrogen. (2) Cotton groups physiological target changes in laws under different furrow irrigation patterns research, the use of the model f=a*exp(-0.5*((T-T0)/b)2) simulation, model parameters and simulation of high precision and stability. Leaf area duration(LAD), crop growth rate (CGR), net assimilation rate groups (NAR), leaf area index (LAI) of the dynamic simulation studies show that the cotton LAD, CGR, NAR, LAI are with the amount of nitrogen application and irrigation increased significantly improve, one of AFI’s LAD, CGR, NAR biggest upgrade, but under high-fat high-water must be inhibited. CFI biggest upgrade of LAI. FFI various groups physiological target were significantly inhibited. Based on cotton groups physiological target changes in the law, as well as biomass, yield relations, draw the cotton group performance at a low fat, low-water situations AFI and CFI than FFI, in manure, water AFI and CFI cases better than FFI , high-fat, high-water situations CFI and AFI is superior to FFI.(3) The law of nitrogen uptake by the model (f=a*exp(-0.5*((T-T0)/b)2)) under different furrow irrigation Analog cotton nitrogen content in various organs, as well as the target of cotton nitrogen absorption changes fitting model parameters are stable and high precision. Total nitrogen content of various organs of cotton (N) under AFI, the proportion of N derived from fertilizer (Ndff) and nitrogen absorption rate (NAR) were not significantly different, in the AFI nitrogen on cotton smaller impact absorption to water conservation and promotion of cotton nitrogen uptake of water and nitrogen coupling effect, improve nitrogen use efficiency of cotton (NUE). fixed every furrow of the organ to absorb nitrogen and nitrogen content were significantly lower target to limit the nutrient uptake of cotton and reduce the NUE. furrow irrigation of cotton nitrogen absorption, the turn of every furrow irrigation can most effectively coupling effect of water and nitrogen to promote the nitrogen absorption and utilization.(4) Different furrow irrigation of cotton root zone water and nitrogen transport studies have shown that the root zone furrow irrigation of cotton on nitrate content with the overall fertility decline over the period. AFI nitrate content of the profile with the irrigation and nitrogen application rate increases, with increasing depth of soil profile and decreased the content of nitrate mainly in the cotton root system within the scope of the effective absorption.

Mots clés : Desert Oasis cotton different irrigation patterns water and nitrogen coupling effect the root zone water and nitrogen transport nitrogen uptake

Présentation (Dissertationtopic)

Page publiée le 5 mai 2013, mise à jour le 1er mai 2018