磷素施用对鲜食糯玉米养分积累分配和产量的影响

以苏玉糯5号和渝糯7号为试验材料,研究磷素施用(A:空白;B:一次性基施P2O575 kg/hm2;C:一次性基施P2O5150 kg/hm2;D:基施和拔节期追施P2O5各75 kg/hm2)对鲜食糯玉米产量、干物质和氮磷钾积累分配的影响。结果表明,穗粒数、子粒鲜重和干重随着磷素施用量增加均显著增加,鲜子粒产量升高,升幅D处理高于C处理。随着磷素施用量增加,植株干物质和氮磷钾积累量均显著升高,磷素施用量P2O5150 kg/hm2时,分次施用较一次性基施植株干物质量和氮、磷、钾积累量分别升高11.1%和16.2%、19.4%、34.5%。鲜食期植株干物质和磷素主要分配于子粒和茎秆,氮素主要分配于子粒和叶片,钾素主要分配于茎秆和叶片。逐步回归分析结果表明,苞叶中干物质分配比例较低、茎秆中氮素分配比例较高、叶片和子粒中磷素分配比例较高、叶片中钾素分配比例较高时有利于糯玉米鲜子粒高产。

Effects of Phosphorus Application on Nutrient Uptake and Distribution and Grain Yield of Fresh Waxy Maize

The effects of P₂O₅ application on waxy maize fresh grain yield, and accumulation and distribution of dry matter, nitrogen, phosphorus and potassium were studied. Four P₂O₅ application treatments, blank(A, without P₂O₅), P₂O₅ 75 kg/haat transplant time(B), P₂O₅ 150 kg /haat transplant time(C), P₂O₅ 75 kg /haat transplant time and P₂O₅ 75 kg/ha at jointing stage(D), and two fresh waxy maize varieties(Suyunuo5 and Yunuo7) were adopted in the present trial. The results observed that with the increment of P₂O₅ amount, the grain number per ear, fresh and dry grain weight gradually increase, result in the increase of fresh grain yield, and the fresh grain yield were higher when apply both P₂O₅ 75 kg/haat transplanting time and P₂O₅ 75 kg/haat jointing stage than apply P₂O₅ 150 kg/haat transplanting time. The dry matter, nitrogen, phosphorus and potassium accumulation amount gradually increase with P₂O₅ rate raise, and the values of those four parameters were increased 11.1%, 16.2%, 19.4% and 34.5%, re- spectively when the 50%(P₂O₅ 75 kg/ha) were top-dressed at jointing stage than apply all(P₂O₅ 150 kg/ha) at trans- planting time. At fresh stage, the dry matter and phosphorus were mainly located in grain and stem, nitrogen was mainly located in grain and leaf, while potassium was mainly located in stem and leaf, respectively. The results of stepwise regression analysis indicated the low distribution percentage in bract for dry matter, low percentage in stem for nitrogen, high percentage in leaf and grain for phosphorus, and high percentage in leaf for potassium would bene- fit for achieving high fresh grain yield of waxy maize.