湖北省油菜磷肥施用效果 与土壤速效磷分级标准研究

近两年在湖北省油菜主产区布置27个油菜大田施磷试验。试验统计结果表明,油菜施用磷肥具有明显 的增产和增收效果, 25 个试验施磷增产效果在5%以上,施磷增产油菜籽产量15 ～1 783kg/hm2 ,平均增产量 558kg/hm2 ,平均增产率为53. 0% ,每千克P2O5 平均增收油菜籽6. 2kg;施磷的纯利润平均为831. 6元/hm2 ,产投比 平均为3. 10。油菜施磷增产幅度与土壤速效磷含量呈极显著负相关。按照不施磷对照处理产量占施磷处理产量 的50%、75%和90%作为判断土壤缺磷标准,则土壤速效磷极度缺乏、严重缺乏和缺乏的指标分别为9. 9mg/kg、 14. 3mg/kg和20. 2mg/kg;以施磷产投比2. 0和1. 0作为土壤缺磷标准时,土壤速效磷严重缺乏和缺乏的指标分别 为16. 2mg/kg和20. 2mg/kg。

Study on response of rapeseed to P application and classification criterion for available P in the soil

27 field trials of phosphate fertilizer(P) application on rapeseed had been carried out in main rapeseed production regions in Hubei province for two years.The result showed that P application both significantly increased rapeseed yield and improved profit.25 trials obtained an yield increase of more than 5 percent with P application,with the increment ranging from 15kg/hm~2 to 1 783kg/hm~2.The average increment was 558kg/hm~2,increased by 53.0 percent and 6.2kg seed yield per 1kg P_2O_5 application compared to the control.The average net profit with P application was 831.6 Yuan/hm~2 and the value to cost ratio(VCR) was 3.10.It was showed that rapeseed yield increment with P application had significant negative correlation with soil available P level.Based on relative yield of CK/ P at 50,75 and 90 percent level,the soil critical available P was 9.9mg/kg for extreme deficiency,14.3mg/kg for serious deficiency and 20.2mg/kg for deficiency,respectively.Based on VCR at 2.0 and 1.0 level,the soil critical available P was 16.2mg/kg for serious deficiency and 20.2mg/kg for deficiency,respectively.