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.