Preliminary Study On The Effects Of Nitrogen From Slow Release Fertilizer On Plant Type And Maturity Performance For Direct Sowing Cotton Planted After Barley Harvested

The study was conducted to investigate the effects of nitrogen from conventional ferilizer (CF) and slow release fertilizer (SR) on yield, plant type and maturity performance for direct sowing cotton planted after barley harvested on 2014 and 2015. The results showed that when the nitrogen amount was 195 kg/hm2, the highest seed cotton yield and lint cotton yield for Guoxinl2-1 (a short season cultivar) were 4014.72 kg/hm2 and 1426.03 kg/hm2, respectively. Under that condition, the population boll number was 113.27×104/hm2, and boll weight was 4.52 g and the lint percentage was 35.5%. Based on those results, the study further investigated the effects of different application and regimes of the nitrogen of SR on the yield of Guoxin 12-1. The results showed that the benefit increased higher with application fertilizer amount at 577.5 kg Lanlishi (SR) (150kg/hm2 pure nitrogen), nitrogen application ratios of seedling period and flowering stage of 100% and 0 respectively. Compared with CF, the yield and benefit under that condition increased by 30.96% and 109.0% respectively.On the way of plant type index developing and centralized boll-setting, the study showed that those were better to concentrated into a bell from 8/15 to 8/30 when plant height, the length of fruiting branch, internode length of main stem, and the ratio of fruit node/fruit branches were optimum and the number of fruit branches and fruit node, internode diameter of main stem, angel between main stem and fruit branch. Under the condition of application 150 kg/hm2 nitrogen from SR on seedling stage, the plant height was 98.6cm, and the angel between the leaf and horizontal plane was higher, and the internoder length of main stem was 6.43 cm, and the diameter of main stem and fruit branch were 0.452 cm and 0.281 cm respectively, and the ratio of fruit node/fruit branches was 3.59, and angel between main stem and fruit branch was 3.59. Those plan type index were appropriate to centralize boll-setting.On the way of maturity performance developing and centralized boll-opening, the study showed that there were significant positive linear correlation between boll-opening percentage and the ratio of yellow leaves/total leaves, the ratio of red-stem/total-stem for main stem, the ratio of red-stem/total-stem for four upper fruit branches (r=0.904**?r=0.959**?r=0.900**? r=0.926**?r=0.928**?r=0.905**). Under the condition of application 150 kg/hm2 nitrogen from SR on seedling stage, the ratio of yellow leaves/total leaves, the ratio of red-stem/total-stem for main stem, the ratio of red-stem/total-stem for four upper fruit branches were all optimum. Thus, the treatment of application 150kg/hm2 nitrogen from SR on seedling stage were better to form optimum maturity performance and centralize boll-opening. It laid the foundation for mechanical harvesting after centralized boll opening.