氮肥前移对果棉间作棉花干物质积累和氮肥利用效率的影响

为探究新疆南疆地区果棉间作下棉花适宜的氮肥追施模式,通过随机区组试验设计(N0:不施氮肥、N1:氮肥追施至初花期结束、N2:氮肥追施至盛花期结束、N3:正常施肥,总N 270 kg/hm~2),研究氮肥前移对遮荫下棉花干物质与氮素积累、氮肥利用效率及产量的影响。结果表明:遮荫下棉花氮肥追施至盛花期结束的N2处理,干物质和氮素积累理论最大值、最大生长速率、生长特征值最大;同时提高了氮肥利用率、氮肥农学利用率、氮肥偏生产力、氮收获指数和最大氮素瞬时利用率,有利于遮荫下棉花干物质、氮素积累分配和营养生长向生殖生长转化,而促进产量的形成。皮棉产量以N2最高,分别比N0、N1、N3提高了33.7%、17.4%、10.7%。所以,在新疆南疆果棉间作下,间作棉氮肥追施应适度前移至盛花期(7月中下旬)结束,有利于提高氮肥利用效率和产量。

Effects of nitrogen topdressing time on accumulation of cotton dry matter and nitrogen fertilizer use efficiency under fruit tree and cotton intercropping

In order to explore suitable mode of nitrogen topdressing time on cotton under fruit tree and cotton intercropping in southern Xinjiang, an experiment was carried out with randomized block design to study the effects of nitrogen topdressing being brought forward on the accumulation of dry matter and nitrogen, nitrogen fertilizer use efficiency and yield under fruit tree shad-ing. The experiment was performed with four nitrogen levels: N0 ( no nitrogen) , N1 ( nitrogen topdressing at initial flowering end of cotton) , N2 ( nitrogen topdressing at full flowering end of cotton) and N3 ( normal fertilization) , total nitrogen appli-cation was 270 kg/ha. Results showed that theoretical maximum accumulation of dry matter and nitrogen, maximum growth rate and growth eigenvalues of N2 were the largest. At the same time, nitrogen fertilizer use efficiency, nitrogen agronomy use efficiency, nitrogen partial productivity, nitrogen harvest index and maximum nitrogen momentary use efficiency of N2 were in-creased. Nitrogen topdressing at full flowering end was helpful to the accumulation and distribution of dry matter and nitrogen, the transformation from vegetative growth to reproductive growth and promotion of yield formation. The lint yield of N2 was high-er than those of N0, N1 and N3 by 33. 7%, 17. 4% and 10. 7%, respectively. Thus, nitrogen topdressing should be appro-priately brought forward to full flowering end ( in the mid and last ten days of July) , it was benefit to increase of yield and ni-trogen use efficiency under fruit tree and cotton intercropping in southern Xinjiang.