不同水分和添加物料对石灰性土壤无机磷形态转化的影响

利用轻粘质土壤 ,模拟石灰性土壤中不同的组分因素进行室内培养试验。结果表明 ,水溶性磷肥施入土壤后很快向其它无机磷形态转化 ,主要转化为Fe-P ,其次是Ca2-P、Ca8-P和Al-P ,而很少转化为O-P和Ca10-P。其转化规律受不同培养组分因素的影响。较低的土壤水分含量 (200g/kg)利于Ca8-P、Al-P向Fe P和Ca10-P的转化 ,过高的水分含量 (200g/kg)有利于Ca10-P的活化与Fe-P的大量生成 ;不同量CaCO3加入促进了Fe-P、Al-P以及Ca2-P向Ca8-P、Ca10-P方向转化 ;秸杆、腐植酸的加入增加了各形态无机磷量以及无机磷总量。随培养时间的延长 ,Al-P、Fe-P等形态的磷量减少 ,Ca8-P、Ca10-P形态的量增加。不同量秸杆以及腐植酸的加入不同程度地降低了速效磷下降的幅度 ,提高了土壤速效磷水平。

Effect of different water and material on inorganic phosphorus transformation in calcareous soil

Incubation experiments indoor were conducted to study on effect of factor of soil constituent on form transformation of inorganic phosphates. The results showed that the applied soluble phosphates rapidly transformed into different inorganic forms, the predominant transformed form is Fe P, then the Ca₂-P, Ca₈-P, Al-P, and the Ca₁₀-P and O-P were much less than other inorganic phosphates. Soil inorganic phosphates transformation was significantly affected by water content and application of different contents of calcium carbonate, humic acid and straw. Ca₈-P、Al-P in light clay soil favorably transformed into Fe-P and Ca₁₀-P under the conditions of low water content (<200g/kg), and high water content(>200g/kg) was disadvantageous to formation of Ca₁₀-P , however, advantageous to the formation of Fe-P. Application of different content of calcium carbonate accelerate the transformation of Fe-P、Al-P , even Ca₂-P into the forms of Ca₈-P,Ca₁₀-P. Application of straw and humic acid increased the contents of all inorganic phosphates and total inorganic content, reduced the extent of decreasing of available phosphorus, and raised the level of available P. Al-P,Fe-P transformed into insoluble calcium phosphate (Ca₈-P,Ca₁₀-P) with the time prolonging.