施氮量对枣棉间作棉花干物质积累，产量与品质的影响

研究了枣棉间作下棉花干物质积累与产量品质对不同施氮量的响应机制，确定枣棉间作的合理施氮量，为果棉间套作立体种植模式的合理氮肥运筹，提高棉花产量与品质提供理论依据。以在南疆的主栽棉花品种中棉所49为材料，研究了4个氮素水平（N 0、 150、 450 和750 kg/hm2）下棉花干物质的积累和产量的差异。结果表明，不同施氮量下棉花干物质累积存在显著差异，氮素缺乏或过量均影响其干物质在不同生育时期的累积量，使产量降低。施氮量对棉花品质也有显著影响，合理的氮肥用量不但能提高棉花单株结铃数和单铃重，从而提高产量，而且可使其有较好的整齐度，棉纤维长度，比强度和马克隆值。因此，在枣棉间作条件下，施氮量为N 450 kg/hm2 时棉花的干物质积累量较高，增产效果显著，品质较好。

Effects of nitrogen fertilization rate in jujube-cotton intercropping on dry matter accumulation and yield and quality of cotton

The aim of this study is to provide theory basis for making nitrogen management optimization and enhancing cotton yield and quality by investigating the effects of different nitrogen levels on cotton growth and determining appropriate N levels in jujube-cotton intercropping system. In this study,  main cultivar CCRI 49 in the Southern Xingjian was selected as experimental material,  and the difference of dry matter accumulation and yield of cotton was analyzed under treatments with 4 levels of nitrogen (N 0、 150、 450 and 750 kg/ha). Results showed that there was a significant difference of cotton dry matter accumulation between different nitrogen treatments. Nitrogen deficiency or excessive application affected cotton dry matter accumulation and distribution,  and had significant effect in different growth period,  and led to yield reduction and decrease of cotton quality,  suggesting that application of nitrogen significantly affect the yield and quality of cotton,  and reasonable nitrogen fertilizer regulation not only can guarantee the increase of boll numbers and boll weight,  but also improve the yield and ensure better uniformity,  better cotton fiber length,  specific strength and micronaire value. We conclude that application of nitrogen 450 kg/ha will obtain better dry matter accumulation of cotton under the jujube-cotton intercropping conditions,  and improve cotton quality.