^32p示踪法研究溶磷真菌对磷肥转化固定和有效性的影响

采用^32P示踪技术，研究了溶磷青霉菌P8对肥料磷与土壤有效磷的转化、固定和有效性的影响．结果表明，溶磷青霉菌菌剂能够增加玉米、花生的生物量，促进作物对土壤和肥料磷素的吸收；溶磷菌剂具有防止有效磷转化为难溶Ca10-P的作用，增加有效态磷(Ca2-^32P、Ca8-^32p)的比例．随时间延长，施入的^32P转化为Ca10-P的数量(或比例)逐渐增加，但是相对于未接种菌剂处理，接种青霉菌菌剂的土壤磷和肥料磷转化为Ca10-P比例最低．溶磷青霉菌菌剂不仅能够防止有效磷向难溶磷Ca10-P的转化，而且其效果能够维持较长时间．

Effects of phosphate-dissolving fungi on transformation,fixation and efficiency of fertilizer 32P

By using a radioactive 32 P-labeled technique,this paper studied the effects of P-dissolving Penicillium oxalicum P8 inoculum on the transformation,fixation and efficiency of fertilizer P.The results showed that the inoculum could prevent available P from fixation by soil,and promoted the uptake of applied P by maize and peanut.Additionally,it reduced the amount of Ca 10 -P fraction derived from available P,increased the pool of available P,and maintained more 32 P in forms of Ca 2-P and Ca 8-P.With time extending,the ratio of Ca 10 -P fraction in soil was gradually increased,and the treatment with P.oxalicum P8 showed the lowest ratio of Ca10-P form,compared with treatment without P.oxalicum P8.The inoculum not only prevented available 32 P from turning into Ca 10 -P form,but also had a longer effective period.