长期定位施肥对碱性紫色土磷素迁移与累积的影响

Transfer and accumulation of phosphorus in the calcareous purple soil in a long-term fertilizer experiment

在25年稻麦轮作长期定位施肥试验点,开展了碱性紫色土水旱轮作种植制度下不同施肥处理土壤剖面全磷、速效磷迁移和累积以及耕层土壤全磷、速效磷随时间的变化规律研究。结果表明,单施无机磷肥土壤磷可迁移至100 cm土层,Olsen-P可迁移至40 cm土层。有机无机磷肥配施不但使土壤磷可迁移至相同深度,且迁移量更大,Olsen-P可迁移至60 cm土层。耕作25年后,施磷处理土壤耕层磷素随时间的变化显著,MNPK处理耕层土壤全磷含量年增长率为0.033 g/kg,Olsen-P的年增长率为2.56 mg/kg。试验表明,连续数年施用足量磷肥后,作物施磷量可根据具体情况酌减,以节约磷肥资源和提高磷肥利用率;施用有机肥促进了磷素从耕层向底层的迁移,是造成土壤磷素迁移的一个重要因素。

Experiments of transport and accumulation of phosphorus in soils was conducted in order to find effective ways to manage and control phosphorus and non-point pollution in crop fields.Different fertilizations were treated in calcareous purple soils in a 25-year rice-wheat rotation field.Factors,such as total phosphours in the soil profile,transport and accumulation of Olsen phosphours（Olsen-P）,and patterns change over time,were studied.Results showed in the soil,phosphorus was detected at 100 cm,and Olsen-P was at 40 cm down to the ground.The application of organic or inorganic P not only increase the depth of P detected in the ground,but also the quantity of P measured in the ground.Meanwhile,Olsen-P was also detected at 60 cm down to the ground with the application of organic or inorganic P treatment.After 25 years treatment,the annual accumulation rate in the plough layer was measured as 0.033 g/kg for total P,and 2.56 mg/kg for Olsen-P for the MNPK treatment.The result suggests that P application rates should be reduced accordingly in order to save the amount of phosphate fertilizer used and to increase the efficiency in the crop field.