盐渍土利用过程中土壤磷素的累积与利用

Accumulation and Crop Recovery of Soil Phosphorus in the Use of Salt-Affected Soil

通过对长期定位试验的研究测定，研究了盐渍土培肥过程中土壤磷素的收支平衡以及磷素累积及其形态。同时．探讨了盐渍土的磷肥利用率。结果表明；通过长期培肥特别是施用磷肥．土壤含磷量有较大幅度的提高．其中大量的磷素被转化为无效的Ca10－P，占无机磷总量的48％。而提高氮肥使用量，合理氮磷配比．有助于降低无效态的Ca10－P的比例。同时．表明作物对磷的需求能力并不因磷肥投入量增加而增加．在一定施磷水平以上，磷肥的利用率随磷肥投入量的增加而下降；合理氮磷配比，提高作物产量，有助于磷肥利用率的提高。

The long-term experiments were conducted to investigate the balance, accumulation and forms of soil phosphorus and crop recovery of fertilizer P in the process of fertility improvement of salt-affected soil. The result indicated that soil P content increased significantly after the long-term fertilizer P application. A large proportion of P was transformed into unavailable form Ca10-P, which accounted for 48% of total inorganic P. Increasing N fertilizer application rate and adjusting proportion N/P ratio could decrease the proportion of Ca10-P form. Crop requirement to P did not increase with the increment of P fertilizer application rate. Above a certain P fertilizer application rate, crop recovery of fertilizer P decreased with the increment of P fertilizer application rate. Proper N/P ratio and high crop yield could increase crop recovery of fertilizer P..