滴灌长绒棉水氮定量耦合效应研究

Coupling effect of water and nitrogen on long-staple cotton under drip irrigation

本研究目的在于在滴灌长绒棉生育期灌水量及施氮量一定条件下，调节不同时期的水氮配比，进一步优化水氮管理，提高产量，为农业生产提供理论指导。试验方法：在长绒棉主产地阿瓦提县，选用新海24号，设9个不同水、氮配比处理，研究生育期生理指标及产量的变化。试验结果：（1）不同时期灌水量变化对长绒棉生育进程的影响大于施氮量变化；（2）不同水氮配比对长绒棉生育前期（7月5日前）及后期（8月1日后）单株叶面积影响较大；叶片净光合速率（Pn）在出苗后45 d左右均达最高值，在出苗后60～75 d迅速下降，Pn最大值第二次出现的时间及下降速率差异较大，9个处理中，以7月5日前灌水130 m3·666．7m-2，追氮10．44 kg·666．7m-2；7月6日至7月31日灌水78 m3·666．7m-2，追氮17．4 kg·666．7m-2；8月1日后灌水52 m3·666．7m-2，追氮6．96 kg·666．7m-2的水氮配比（N3W1）Pn二次峰值出现时间最早，在出苗后75 d，为22．7μmol·m-2·s-1，且持续时间长，下降缓慢；（3）通过对8月21日的单株成铃数分析表明：N3W1处理单株成铃最多，为15．8个·株-1，脱落率最低，仅为41．5％。结论：在滴灌长棉生育期所需纯氮20 kg，灌水约260 m3·666．7m2条件下，以7月5日前灌水130 m3·666．7m-2，追氮10．44 kg·666．7m-2；7月6日至7月31日灌水78 m3·666．7m-2，追氮17．4 kg·666．7m-2；8月1日后灌水52 m3·666．7 m-2，追氮6．96 kg·666．7m-2的水、氮配比方式最利于长绒棉经济产量的形成。

This study aims to optimize combination of water and nitrogen and improve grain yield of long-staple cot-ton,providing guidance for agricultural under drip irrigation conditions .Xinhai 24 cultivar was planted in main cotton ar-eas of Awati Country to investigate the physiological paremeters and grain yield with nine combinations of water and nitro-gen treatments .Effect of water was greater than the amount of nitrogen fertilizer on cotton growth .Combination of water and nitrogen showed marked impact on leaf area per plant at earlier （before 5 th July）and later （after 1 st August）stage of long-staple growth .Net leaf photosynthetic rate （Pn）achieved the greatest values 45 days after seeding,and then de-creased rapidly 60~75 days after seeding .The second time of the greatest values of Pn and descending rate showed sig-nificant difference .Analysis of boll number per plant indicated that N3W1 has the greatest boll number per plant,which was 15 .8·plant-1,and shedding rate was the lowest,being 41 .5%.Drip irrigation was 130 m3·666 .7m-2,nitrogen was 10.44 kg·666.7m-2 before July 5th;drip irrigation was 78 m3·666.7m-2,nitrogen was 17.4 kg·666.7m-2 be-tween July 6 to July 31;drip irrigation was 52 m3·666.7m-2,nitrogen was 6.96 kg·666.7m-2 after August 1st.in ad-dition,the combination of 20 kg nitrogen and 260 m3 water·666 .7m-2 showed the better performance .