| This study aims to optimize combination of water and nitrogen and improve grain yield of long-staple cotton, providing guidance for agricultural under drip irrigation conditions. Xinhai 24 cultivar was planted in main cotton areas of Awati Country to investigate the physiological paremeters and grain yield with nine combinations of water and nitrogen treatments. Effect of water was greater than t
he amount of nitrogen fertilizer on cotton growth. Combination of water and nitrogen showed marked impact on leaf area per plant at earlier (before 5th July) and later (after 1st August) stage of long-staple growth. Net leaf photosynthetic rate (Pn) achieved the greatest values 45 days after seeding, and then decreased rapidly 60～75 days after seeding. The second time of the greatest values of Pn and descending rate showed significant 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 between 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 addition, the combination of 20 kg nitrogen and 260 m3 water·666.7m-2 showed the better performance. |