淹水时间对水稻土磷素形态转化及其有效性的影响

Effect of Flooding Time on Phosphorus Transformation and Availability in Paddy Soil

水稻土淹水后土壤中P的形态及其有效性发生了变化,为掌握淹水时间对这种变化影响的规律,选择太湖地区典型水稻土—黄泥土为试验样本,在室内进行了不同淹水时间的土壤培育试验,并采用新鲜土壤样品测定的方法,研究了淹水时间对土壤P素形态转化及其有效性的影响。结果表明:①淹水时间主要影响Fe-P、O-P、Ca10-P和Ca8-P的转化。与淹水前相比,淹水使Fe-P和Ca8-P增加、O-P和Ca10-P减少,其中,Fe-P和Ca8-P分别于淹水45和15天后增加最为显著并趋于稳定,此时分别增加了194和9.6 mg/kg(分别占淹水前的93%和73%);O-P和Ca10-P于淹水15天后减少最为显著并趋于稳定,此时分别减少了72和20 mg/kg(分别占淹水前的24%和27%);②淹水改变了水稻土P素有效性及有效P的数量,与淹水前相比,淹水45天,水稻土P素有效性及有效P的数量最高,有效P增加了32 mg/kg(占淹水前的57%)。结论:淹水时间影响着水稻土P素形态转化、有效性以及有效P的数量,淹水45天,水稻土P素形态转化数量最大、有效性最高和有效P的数量最大。

Phosphorus form and availability of paddy soil may change after flooding, in order to know the change laws, selecting Huangnitu, a typical paddy soil, to cultivate at different flooding time in Taihu Lake Region, using fresh soil determination to study the effects of phosphorus transformation and availability at different flooding time. The results showed that flooding time mainly influenced the transformation of Fe-P, O-P, Ca10-P and Ca8-P. Compared with the previous flooding, Fe-P and Ca8-P increased but O-P and Ca10-P decreased. Fe-P increased significantly and then stabilized in 45 days, Ca8-P in 15 days, Fe-P and Ca8-P increased 194 and 9.6 mg/kg respectively （accounting for 93% and 73% before flooding）. Compared with the previous flooding, Phosphorus availability and the amount of available phosphorus were to the highest level in 45 days, available phosphorus increased 32 mg/kg （accounting for 57% before flooding） at this time. Flooding time affects phosphorus form transformation/ availability and the amount of available phosphorus. The amount phosphorus form transformation and available phosphorus as well as phosphorus availability were to the highest in 45 days.