氮钾肥施用次数对夏直播棉花干物质积累、产量和养分利用率的影响OA北大核心CSTPCD

[Objective]To improve the yield of summer direct seeding cotton in the Yangtze River basin,this study focuses on the effects of nitrogen(N)and potassium(K)application frequency on cotton.[Methods]Field experiment was conducted in 2021 and 2022 under a randomized complete block design in a split-plot arrangement,where K fertilizer(210 kg·hm-2)application frequency K1[pre-plant fertilizer(PP)100％]and K2[PP 50％+first flowering fertilizer(FF)0 d 50％]were kept in the main plot,and the sub-plots were allocated with N fertilizer(210 kg·hm-2)application frequency:N2[PP 20％+FF 0 d 80％],N3[PP 20％+FF 0 d 60％+FF 21 d 20％],and N4[PP 10％+FF 0 d 50％+FF 7 d 30％+FF 21 d 10％].The effects of different treatments on cotton dry matter accumulation and allocation,N and K accumulation and allocation,yield and yield components,and nutrient utilization efficiency were studied.[Results]The dry matter mass and the accumulation of N and K at plant removal stage,and the duration and average accumulation rate of the rapid accumulation period of dry matter in cotton plant,source,flow,and sink organs under K2N3 treatment were lower than those of K2N4 treatment,but the distribution ratio of dry matter,N,and K in the sink organs were higher than those of K2N4 treatment.K2N3 resulted in higher seed cotton yield and lint cotton yield,which were 31.4％and 31.9％significantly higher than the lowest yield treatment K1N2,respectively.However,further increase of N application times(K2N4 treatment)did not result in significantly higher cotton yield.There is no significant difference in the partial productivity of N and K between K2N3 and K2N4 treatments,but both are significantly higher than the other treatments.Principal component analysis showed that the main difference in cotton yield comes from the number of bolls,and promoting the allocation of biomass,N and K nutrients to sink organs is beneficial for improving yield.[Conclusion]For the direct seeding cotton after wheat in the Yangtze River basin,two times of K application combined with three times of N application can increase the absorption of N and K,promote dry matter as well as N and P distribution to sink organs,thus increase the number of bolls,and improve cotton yield.