Study On Dry Matter Accumulation,Yield And Quality Formation Under Short Season Cotton Cultivation

Very early maturing cotton new variety "JX0010" was used in this research as test material with quadratic regression design (311 designs) of quadratic regression combination design. The field experiment was conducted to study the effects of cultivation factors on the cultivation of cotton growing period, agronomic traits, dry matter accumulation, distribution law, spatial and temporal distribution of cotton bolls, and the impact on cotton yield and fiber quality. The main findings were as follows:1. Cotton sowing is the main factor affecting growth period, than the amount of nitrogen, followed by density minimal impact, reasonable density and the suitable seeding time can reduce the cotton growth period, the growth period will be extended if density is too low or too high, early or late sowing of cotton, increasing of nitrogen will extend the cotton growth period under the experimental conditions.2. Sowing date, nitrogen fertilizer and density has a significant effect on cotton agronomic traits. The results show:Influence of plant height showed sowing> nitrogen> density. Under the experimental conditions, Plant height with increasing nitrogen rate increased with increasing density decreases with delayed sowing and reduced, on the performance of branch sowing> density> nitrogen rate, the number of fruiting branches per plant increased with the amount of nitrogen, sowing delayed decline after the first rise, and with the increase of density, reduce the number of fruiting branches per plant.3. Cotton plant vegetative organs and reproductive organs dry matter accumulation dynamics are basically the same, in line with an "S" curve variation, early dry matter accumulation of cotton grown more slowly, the medium-term accumulation speed, the dry matter accumulation flatten. Density is the main factor affecting the vegetative organs and reproductive organs plant dry matter accumulation, nitrogen rate, followed by sowing minimal impact.The cotton population dry matter accumulation increased with the advancement of growth period, and biggest in the 9th treatment (1374.4 kg/667m2) and increased by 15.74%～137.48% than other treatments.4. The highest proportion was summer peach in the 8th treatment and reached 69.63%. In the other treatments, the autumn peach was most and reached 53.69%-81.87%. Through the establishment of the tested factor and proportional regression model autumn boll, the results showed that the tested factor on cotton autumn peach size, ratio of performance for sowing> Nitrogen> Density, under the experimental conditions, with increasing amount of nitrogen, autumn peach proportion after first increased and then decreased. A reasonable amount of nitrogen will help improve cotton autumn peach proportion with the increase of density, the proportion of autumn peach downward trend, with the delayed sowing of autumn peach risen.5. Mathematical models of new line cotton "JX0010" of yield of seed cotton and nitrogen rates, density, sowing under short season cultivation were established. Y=218.3412+7.4972xi+7.3074x2-21.1258x3-7.5729x12-1.7816x22-5.7490x32-12.43375x1X2-4 .2228x1X3+2.6149x2X3. Single factor effect manifested as sowing> density> nitrogen rate, and two factor effect manifested as the interaction of nitrogen and density> the interaction of sowing and density> the interaction of nitrogen and sowing. From the regression equation, when nitrogen application was 13.28kg/667m2, the density was 4704 plant/667m2, sowing date was June 1, production was higher than 237.77kg/667m2.6. The order that cultural factors affecting cotton fiber quality traits was micronaire> breaking strength> upper half mean length> uniformity index> elongation. The cultural factors affecting micronaire of cotton fiber was sowing> density> nitrogen rate, affecting elongation of cotton fiber was sowing> density> nitrogen rate, affecting uniformity index of cotton fiber was sowing> nitrogen rate> density, affecting breaking strength of cotton fiber was density> nitrogen rate> sowing and affecting upper half mean length of cotton fiber was density>sowing>nitrogenrate.Y=0.7154+0.0363x1+0.0776x2-0.0495x3+0.0058x12-0.0178x22-0.1145x32-0.0104x1x2+0.0161x1x3-0.0023x2x3 was established according to the objective function of fiber quality composite score and single factor effect performance density>sowing of> Nitrogen. Through simulation optimization, get the best combination of fiber quality when nitrogen was 25kg/667m2, density 5096 plant/667m2, sowing date was May 25, the fiber quality composite score was 0.8575.