Nitrogen Use Efficiency Of Cotton

In this paper, According to the current level of production of nitrogen fertilizer, Transplanting hybrid cotton by pot, Set 5 different nitrogen levels by isotope (A:0kg/667m2; B:10kg/667m2; C:20kg/667m2; D:30 kg/667m2; E:40 kg/667m2),3 points fertilization (Basal dressing:First blooming:Peak blooming=3:4:3).sign each fertilization, Discuss influence of different nitrogen levels on the chlorophyll content of cotton yield and its component factors; Determine the reasonable amount of nitrogen. Clear allocation and utilization of nitrogen in the cotton stages; understand the effects of residual nitrogen; the results showed that:1 Effects on the chlorophyll contentIncreased chlorophyll content of cotton with the increase of nitrogen fertilizer, is E>D>C>B>A. In the whole growth period, Fluctuations of chlorophyll content in same level. Nitrogen content and chlorophyll content was significantly positive correlation.2 Effects on the biomassPlant biomass and daily growth of biomass increased with nitrogen fertilizer. After the emergence 98d, Biomass growth rate began to decline. Nitrogen nutrition did not affect the relative amounts of organ. There are some differences in the amount of dry matter in Nitrogen.3 Effects on yield and its componentsIncreased seed cotton yield per plant when N increases, but magnitude smaller, and there are no significant difference in yield between D and E. So 20-30kg/667m2 is the best nitrogen fertilizer. Nitrogen application increased the boll weight, but has no affect with amount. Increase the amount of nitrogen fertilizer can increase boll opening, so if we want to increase yield, we can increased boll weight and boll opening.4 Effects on fiber qualityUnder the conditions of this experiment, N fertilizer could improve cotton fiber micronaire value, have no significant effect On the other fiber quality.5 Utilization of NUtilization is very low on basal dressing and peak blooming fertilizer, but utilization is very high on first blooming fertilizer, but utilization is high in fertilization stage on first blooming and peak blooming fertilizer. When the nitrogen content increases, the utilization rate increased. There are small differences in the utilization of the basal between D and E. On the first blooming fertilizer utilization, E increased by 12.84% compared with D, and on the peak blooming fertilizer utilization, E increased by 9.75% compared with D. So 40kg/667m2 is excessive nitrogen. Utilization of the first blooming fertilizer is the biggest. High nitrogen fertilizer to drop N efficiency of agriculture and Partial productivity, Excess nitrogen is not conducive to the formation of economic yield.6 Distribution characteristics of nitrogenDistribution proportion of nitrogen fertilizer in 50.71%-74.87% in seedling stage, the main source is base fertilizer in seedling stage. Absorb increase on basal dressing fertilizer in bud stage, but DP has dropped, so we see the main source of low N is nitrogen derived from the soil in bud stage. Because use first blooming fertilizer, More on the first blooming fertilizer uptake of cotton in first blooming stage, Small differences in base fertilizer during treatments, at this stage, first blooming fertilizer Play a major role. In peak blooming stage, contents of base fertilizer and first blooming fertilizer has dropped, because N is moving in this stage. The same as next stage, Among treatments, Nitrogen from fertilizer nitrogen content was E>D>C>B, and large proportion of soil nitrogen on treatment B, fertilization of treatment B can not satisfy the growing demand for cotton, fertilize nitrogen content of leaves is the highest in seedling and bud stage, but in other stages bolls is.7 Effects of residual nitrogen on the second quarter of cottonResidual nitrogen on Chlorophyll content and yield of second cotton had no significant effect, utilization of residual nitrogen on the lower level.8 Quadratic residue rate of NAfter the two cotton-growing, quadratic residue rate is high, quadratic residue rate of base fertilizer on treatment B, When the nitrogen content increases, the residual rate of decline.