磷肥施用对红壤有效磷含量和易流失磷含量的影响

目的]该研究旨在探讨好气培养条件下,不同磷肥施用量的红壤中,应用Olsen法和Bray-1法测定的土壤有效磷含量及应用CaCl2法测定的土壤易流失磷含量的变化及其相关关系,为红壤区的磷素管理及磷素流失潜力评价提供理论依据。方法]试验共设6个土样处理,室内好气培养后测定各土样中Olsen-P、Bray-1-P和CaCl2-P含量。结果]随培养时间的延长,施用不同量磷肥的红壤中Olsen-P含量逐渐降低,Bray-1-P含量逐渐升高,CaCl2-P含量呈先升高后降低的趋势;CaCl2-P含量与Olsen-P含量和Bray-1-P含量均呈线性相关关系;肥料磷进入红壤Bray-1-P库的比例高达62%,进入Olsen-P库的比例为14%,进入CaCl2-P库的比例为0.12%。结论]好气条件下施用磷肥造成红壤磷流失的风险不大,但随施磷量的增加,磷流失潜能仍会升高,且在施磷初期流失潜能最高。

Influence of Phosphorus Fertilizer Application on Available Phosphorus and Easy-loss Phosphorus Content in Red Soil

This study was to study the influence of phosphorus(P) fertilizer application on available P and easy-loss P content in red soil under aerobic incubating condition,with the aim to provide theoretical basis for the management of elemental P and evaluation of elemental P loss potential.Method] Totally six treatments were set to the soil samples.The Olsen-P,Bray-1-P and CaCl2-P contents of each soil sample were measured after indoor aerobic incubation.Result] In the red soil of different P fertilizer application rates,the Olsen-P content decreased with the increasing of incubation time,while the content of Bray-1-P increased and CaCl2-P content was first increased then decreased.CaCl2-P content was linear correlated with Olsen-P content and Bray-1-P content.About 62% P fertilizers were transformed into Bray-1-P pool,and 14% into Olsen-P pool,but only 0.12% transformed into CaCl2-P pool.Conclusion] There is little risk of P loss caused by P fertilizer application under aerobic condition,but P loss potential would increase with the increasing application dose,which was most serious in the primeval period after P fertilizer application.