长期培肥对作物生育后期土壤速效磷含量的影响

经过长期定位试验，建立土壤速效磷与农肥、化肥、秸秆关系的数学模型并探讨作物生育后期土壤速效磷合量的变化规律。分析表明，作物生育后期，土壤速效磷含量随农肥用量增加而呈上升趋势；而化肥效益随着用量的增加而迅速下降；在农肥、化肥用量较高时，秸秆的效果较好；农肥、化肥用量较低时，效果不明显，农肥、化肥、秸秆之间存在着明显的正文互作用。

THE EFFECT OF LONG-TERM FERTILIZING ON RAPIDLY AVAILABLE PHOSPHATE IN SOIL DURING LATE GROWING STAGE

A mathematical model of the relationship between available P in soil and manure, chemical fertilizer and straw was made through long-term location test:Y(S) = +73.1226 0.7674S1+44.0141S2+13.7365S1+4.1295S1S2+0.2942S1S3+5.0912S2S3- 0.129271714S1-70.5052S2-￣ 5.4813S3A regularity of variation of available phosphate in soil during late growing stage was analyzed. The results show: available phosphate increases with the.input of manure during late growing stage, but decreases rapidly with the increase of chemical fertilizer; straw is good fo fincreasing the content of available phosphate when the inputs of manure and fertilizer archigh, but with no obvious increase when.the inputs of manure and fertilizer arc low There isan obvious orthogonal interaction among manure,chemical fertilizer and straw.