Establishment And Effect Research Of Optimized Nitrogen Management System In Cotton Field

By many farmers' investigation, they were used to applying mass water and N fertilization input, serious blindness on water and fertilization management, attach importance of basic manure, which was not unfit for the rule of cotton required fertilization, so it will waste badly resource and lead to possible negative effect on environment. The study intended to establish an optimized nitrogen management system, in which resources could be utilized with high efficiency, constituted by optimized N fertilization at different stages, optimized irrigation and optimized farm manage way. A field trial was carried out to research the effect of optimized nitrogen managerial system on cotton economic yield, N balance and effect on soil environment by comparing those of conventional nitrogen managerial system and control. The main content as follows:(1) The yields of optimized N fertilization treatment and conventional N fertilization treatment were no significant differences and all achieved target yield. The quality was as so.(2) The amount of accumulated biomass and N absorptivity between optimized N fertilization treatment and conventional N fertilization treatment was not significantly difference at before beginning flowers; while after beginning flower, conventional N fertilization treatment was higher than that of optimized N fertilization treatment.(3) Apparent N recovery of optimized N fertilization treatment were 58.9%,81.1%, which was average higher 23.15% than conventional N fertilization treatment(45.6%,48.1%)ï¼›N use efficiency of optimized N fertilization treatment was19.9 and 22.7, which was average higher 11.15 than conventional N fertilization treatment(9.9,10.4).(4) The input and output of nitrogen were almost balanced on the whole season in optimized N fertilization system, while in conventional N fertilization treatment it represent great discrepancy between cotton development prophase and anaphase and the mean nitrogen loss was 132kg/hm2.(5) After cotton harvest soil NO3--N of optimized N fertilization treatment was concentrated in 60~90cm, and it was lesser in 90-200cm soil layer, which was appreciably higher than conventional N fertilization treatment, while in conventional N fertilization treatment abio-N fertilization move mainly 90-200cm soil layer.(6) The experiment showed that optimized nitrogen management system was excellent than conventional nitrogen management system on utilization of resource and economic efficiency. And the study proved that the way of soil Nmin fertilization recommendation was a preferable one.