| Cotton is an important cash crop in Xinjiang.With the popularization of mechanical picking,leaf shedding rate and canopy structure are important factors affecting the efficiency of mechanical picking.Due to the reduction of plant spacing in 76 cm row spacing pattern,there is a decrease in yield.Use planting density and nitrogen fertilization on the compensation effect of individual and group,further optimize upgrade 76 cm row spacing machine pick cotton planting pattern of photosynthetic characteristics,for improve the quality of mechanical harvest and production base,southern xinjiang typical mechanical harvest area 76 cm row spacing cultivation mode,set up three planting density and n application rate of 3analysis 76 cm row spacing mode density and nitrogen model of machine adopt regulatory role of cotton,draw lessons from predecessors’ theory and practice to explore,on the basis of our research,compiled a set of machine adopt sustainable cotton planting mode high production and efficiency of resource utilization pattern and the improvement measures,It provides reference for the integration of mechanical picking and mechanical technology in Xinjiang.The main research results are as follows;(1)The results showed that with the increase of nitrogen application rate,the LAI of cotton population increased first and then decreased,in which the interception rate of population increased and the change range of bottom layer was larger;With the increase of density,the change trend of leaf area index of cotton population was consistent with the change trend of nitrogen application rate,and the interception rate of cotton population near the Bank of China increased slowly.M2N2 treatment made the spatial distribution of light in the canopy more uniform,and had the ability of automatic adjustment to improve canopy interception,which made the canopy distribution more reasonable.(2)The results showed that the initial fluorescence,quantum actual yield,net photosynthetic rate and maximum actinology efficiency increased with the increase of nitrogen rate,but the trend was opposite with the increase of nitrogen application rate.The Fv/ Fm of cotton leaves had little difference at the early growth stage.Under the interaction of the two factors,with the advancement of growth process,the net photosynthetic rate of M2N2 treatment was higher than that of other treatments,followed by M1N3 treatment.The results showed that under the condition of conventional density,the use of conventional nitrogen application was beneficial to improve the photosynthetic rate of cotton population and the photosynthesis in later stage.(3)Density,nitrogen fertilizer and their interaction had significant effects on Agronomic Traits and dry matter accumulation of cotton.With the increase of planting density,the increase of cotton dry matter accumulation and boll number was closely related to the distribution of reproductive organs,single boll weight,maximum dry matter accumulation and rapid accumulation.With the increase of nitrogen application rate,the maximum dry matter of cotton plant and boll increased first and then decreased,and the maximum growth rate was lower,while the proportion of reproductive organs decreased.Under the interaction of density and nitrogen fertilizer,the average dry matter accumulation per plant of cotton population increased by 36.73 g under M2N2 treatment,and the maximum rapid accumulation rate of dry matter per plant was 3.78 g plant-1 D.at this time,the maximum dry matter accumulation per plant increased by 25.39%,and the rapid accumulation time prolonged by 16.06%.Compared with the treatments of M1N1、M1N2、M1N3、M2N1、M2N3、M3N1、M3N2、M3N3,the average yield of seed cotton increased by 2.21%～5.92%,and the agronomic efficiency of nitrogen fertilizer(NAE)increased by0.82～2.98. |
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