氮肥基追比对杂交棉光合生理特性及产量的影响

effects of base and topdressing nitrogen fertilizerswith different ratios on the physiological characteristics of functional axial leaves and yield of hybrid cotton

在南疆自然生态条件下，研究三种氮肥基追比（N1，基肥∶追肥＝0∶10；N2，基肥∶追肥＝2∶8；N3，基肥∶追肥＝4∶6）对杂交棉兆丰1号和鲁棉研30号主茎功能叶光合生理特性及产量的影响。结果表明，在总施氮量相同的条件下，随着氮肥追施比例的减少，主茎功能叶生理特性呈先增后减的趋势。进一步分析指标参数知，零基肥处理显著降低了叶面积指数（LAI）、主茎功能叶 SPAD 值、硝酸还原酶（NR）活性和可溶性蛋白质（SP）含量，峰值出现日提前20 d ，植株早衰；N3处理花铃后期 SPAD 值、NR 活性与 SP 下降幅度大，分别下降了31．08％～32．04％、57．12％～74．55％和78．53％～80．79％，至吐絮期光合速率较最大值下降了66％左右，减少了光合产物向棉铃中转移量；兆丰1号和鲁棉研30号氮肥基追比均以2∶8处理条件下主茎功能叶各项参数最为协调，叶片叶绿素含量提高了5．04％～25．44％，改善了叶片光合性能，延长了叶片功能期，延缓了杂交棉中下部叶片衰老速度，增加单株成铃，提高铃重，皮棉产量达4233．3 kg·hm -2以上。兆丰1号皮棉产量低于鲁棉研30号 ，除 N1处理外 N2，N3处理差异显著。

To investigate the effects of base and topdressing nitrogen fertilizers on the photosynthetic biochemical characteristic of functional leaves of hybrid cotton in Nanjiang ,fertilizers with three different compositional ratios （base vs .topdressing fertilizers of N1 ,N2 ,and N3 were 0∶10 ,2∶8 ,N3 ,and 4∶6 ,respectively ） were employedusing Zhaofeng 1 and Lumianyan 30 .Results showed that when equal amounts of total nitrogen were applied ,with the reduction of topdressing nitrogen ,the physiological indexesof the main functional stem leaves tended to increase first and then be-came decreased .According to additional analysesof the related indexes ,zero base fertilizer treatment had significantly re-duced the LAI and SPAD values of the main functional stem leaves ,and the activities of nitrate reductase and soluble proteins ,peak values of which appeared 20 daysearlier ,resulting in an earlysenescence process .With N3 treatment , SPAD value ,NR activity and SP content at the post-flower-boll stagehad decreased quickly ,reaching the levels of 31 .08% ~ 32 .04% ,57 .12% ~ 74 .55% ,and 78 .53% ~ 80 .79% ,respectively .Additionally ,at the boll opening stage ,the photosynthetic rate was reduced approximately 66% fromthe maximum ,minimizing the transfer of the photosyn-thetic products to the bolls .It was further found that when Zhaofeng 1 and Lumianyan 30 were treated with the 2∶8 fertil-izer ,the indexes of the main functional stem leaves seemed to be balanced ,increasing 5 .04% ~ 25 .44% of leaf chloro-phyll content ,improving the performance of photosynthesis ,extending the functional period of leaves ,postponing senes-cence of the leaves at the middle and the lower portions ,and enhancing the weight per boll and the lint yield to 4 389 .89 kg·hm - 2 .Lint yield of Zhaofeng1 was lower than that of Lumianyan30 ,which was found to be significantly different with N2 and N3 treatments but not N1 .