氮肥追施模式对遮阴下棉花光合效率及产量的影响

Effects of Nitrogen Dressing Schedule on Photosynthetic Efficiency and Yield of Cotton Plant in Shade

通过探讨果棉间作下棉花适宜的氮肥追施模式,为间作棉田合理氮肥施用提供理论依据。以中棉所49为试验材料,设置不遮阴(CK)和遮阴50%处理,每个处理3个氮肥追施模式N_1(氮肥前移)、N_2(正常追肥)、N_3(氮肥前移比例较N_1大),研究氮肥追施对遮阴膜下滴灌棉花光合特性和产量的影响。结果表明:与CK相比,遮阴50%处理下棉花叶片叶绿素含量和叶面积指数增加,净光合速率下降,伏前桃比例减少,秋桃比例增加。遮阴50%处理下,氮肥追施适当前移(N_1),可提高棉花光合速率,促进光合产物的形成与积累,增加伏桃比例,显著提高了单株铃数、单铃重和皮棉产量。因此,可以考虑将氮肥适量前移(N_1),作为果棉间作下棉花提高光能利用率和产量的有效途径。

The purposes of this study were to explore the appropriate nitrogen dressing schedule under fruit and cotton intereropping and provide the theoretical basis about the rational nitrogen application for intercropping cotton field. The experiment material was the central cotton No. 49 and performed without shade （CK） and with 50% shade, and three nitrogen dressing schedules, i. e. the N1 （ nitrogen dressing forward）, N2 （ normal nitrogen topdressing） and N3 （the proportion of nitrogen dressing forward was higher than that of N1 ） ,were designed for each treatment so as to explore the effects of nitrogen dressing on the photosynthetic characteristics and yield of cotton in shade under drip irrigation under mulch. The results showed that the chlorophyll content and leaf area index of cotton plant in 50% shade were increased, the net photosynthetic rate was decreased, the proportion of bolls before hot summer days was decreased, and the proportion of autumn bolls was increased compared with those in CK. Under 50% shade,the photosynthetic rate of cotton plant under nitrogen dressing forward （N1 ） was appropriately increased, the formation and accumulation of photosynthetic products were promoted, the proportion of bolls before hot summer days was increased, and the bolls per plant, weight per boll and lint yield were significantly increased. Therefore, the nitrogen dressing forward （ N1 ） could be considered as an effective way to improve the efficiency of solar energy utilization and cotton yield under fruit and cotton intercropping.