利用大田试验研究了不同磷肥用量对甘蓝型春油菜产量、养分积累、磷素利用效率和经济效益的影响.结果表明,在低磷土壤上施用125 kg/hm2 N和135 kg/hm2 K2O基础上增施磷肥,可显著增加油菜不同部位产量,其中籽粒产量平均提高12.5％,生物量平均提高29.0％.施磷明显提高油菜地上部P素含量,有利于促进油菜K素营养累积,但对N素、K素含量无显著影响.随磷肥施用量的增加,磷肥偏生产力显著下降,施磷后磷肥农学效率、磷肥表观利用率和磷肥生理利用率平均分别为4.6 kg/kg P2O5、13.0％和40.2 kg/kg P2O5,磷肥对籽粒产量的贡献率仅为10.9％.根据经济效益分析结果,青海甘蓝型春油菜生产中磷肥用量以75 kg/hm2为宜.%Hie effect of humic substances on the movement of phosphorus ( P) in a cinnamon were studied through an incubation experiment using soil column. The results showed that compared to monocalcium phosphate alone, the movement distances of added P were reduced by sodium humate, which also declined the P movement amount and the concentrations of water-extractable P and acid-extractable P in fertilizer microstates. Conversely, humic acid applied with monocalcium phosphate together increased the distance and amount of P movement as well as the concentrations of P in different forms. Therefore , humic acid could promote the movement and transformation of P in cinnamon soil and was recommended to be applied with P fertilizer together. However, sodium humate was not suitable for co-application with P fertilizer.
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