紫色土减磷配施有机肥的磷肥效应与磷素动态变化

Effect of Reduced Phosphorus Fertilizer Combining Organic Fertilizers and Phosphorus Dynamics Changes in Purple Soil

为探索长江上游稻油轮作系统减少农田磷素流失和有效提高磷肥利用率的最佳施肥模式,降低磷对水体富营养化的影响,采用长期田间定点试验并结合室内试验分析,研究了化肥配施猪粪和水稻秸秆还田对紫色土磷肥效应及磷素迁移的影响。结果表明：在常规作物施肥基础上配合施用有机肥,适当减少化学磷肥施用量,对作物产量没有显著的减产效应,且能在一定程度上减少农田磷素损失,提高磷肥利用率。水稻磷肥利用率总体表现为常规施磷量减20%＋猪粪有机肥（MDP）〉常规施磷量减20%＋秸秆还田（SDP）〉常规施肥＋猪粪有机肥（MP）〉常规施肥＋秸秆还田（SP）≈优化施肥（P）,各处理利用率在20%-25%之间。油菜磷肥利用率总体表现为SDP〉MDP〉MP〉SP〉P,各处理利用率在17%-29%之间。在水稻生长前一个月内,田面水总磷含量随着施磷水平的增加而增加,其中常规施肥（P）比不施磷肥（P0）处理总磷含量高4倍左右。各处理中磷含量大小表现为P〉MP〉SP〉MDP〉SDP〉P0,配施有机肥可以提高稻田土壤对磷的吸附,降低前期土壤磷向水体中释放,配施秸秆比配施猪粪对减少土壤磷素流失效果更好,磷肥施用后的7-10天内是控制稻田磷素流失的关键时期。油菜蕾苔期的土壤有效磷含量较苗期明显降低,但在油菜开花期和收获后期,土壤有效磷含量明显上升,油菜生长花期以后是土壤有效磷淋失的主要时期。有机无机肥配施可以显著提高土壤有效磷含量。化学磷肥减量并配施有机肥是应对农业面源污染＂控源节流＂的较好措施。

In order to explore the optimum fertilization model for reducing the loss of phosphorus in farmland and improve the utilization ratio of phosphate fertilizer in the Yangtze River Basin,as well as reduce the threat to the water quality of the Yangtze River,a long-term field experiment and laboratory analysis were carried out to study the effect of phosphate fertilizer and phosphorus element transportation on chemical fertilizer application combined with pig manure and rice straw in purple soil.The results showed that the application of reduced chemical fertilizers combined with organic fertilizer did not significantly affect crop yield,and to some extent it could reduce agricultural phosphorus loss and improve phosphorus utilization.The utilization rate of phosphate fertilizer by rice showed that pig manure＋20% reduced conventional phosphorus fertilizer（MDP）〉straw＋20%reduced conventional phosphorus fertilizer（SDP）〉pig manure＋conventional phosphorus fertilizer（MP）〉straw＋conventional phosphorus fertilizer（SP）≈optimal fertilizer（P）,with the utilization rate of phosphate fertilizer between 20% to 25%in all treatments.The utilization rate of phosphate fertilizer of rape listed in the order of SDP〉MDP〉MP〉SP〉P,with the utilization rate of phosphate fertilizer between 17% to 29%.In the first month of rice growth period,total phosphorus content in field surface water increased with the increase of the levels of phosphorus fertilizer,and that in theconventional fertilization（P）treatment was 4times higher than that in no P fertilizer（P0）.The phosphorus content listed in the order of P〉MP〉SP〉MDP〉SDP〉P0.Combined application of organic manure in paddy soil could improve the phosphorus fixation and reduce early phosphorus release to the water,and straw showed better effect than pig manure.The critical period of field control of phosphorus loss was 7to 10 days after adding P fertilizer into the field.The available P content was much lower in bud stage of rape than in seedling stage,but it increase significantly in flowering stage and the later stage of rape.It was the main period of soil phosphorus leaching after flowering period of rape.The application of organic and inorganic fertilizer could significantly increase the content of available phosphorus in soil,and chemical phosphate fertilizer reduction and combined application of organic fertilizer is a good measure to deal with ＂control source and curb loss＂of agricultural non-point source pollution.