太湖地区典型水稻土中速效磷变化规律研究

为了定量研究太湖地区农田土壤中速效磷的变化情况,本文对不同季节太湖地区三种典型水稻土(白土、黄泥土和乌栅土)中土壤速效磷的含量进行了分析。结果表明:速效磷含量在土壤剖面中由上层到下层呈现逐渐递减的趋势。三种土壤均以耕层含量为最高,在45cm以下基本上趋于稳定,但在接近地下水时又略有上升。季节性变化方面,速效磷含量一般在2月份的小麦分蘖-拔节期和9月份的水稻齐穗期较高。影响土壤速效磷含量的因素很多,经分析:土壤速效磷的含量与土壤的有机质含量呈极显著的线性正相关关系;旱作条件下与全磷含量之间呈显著的幂函数相关关系,在水作条件下与全磷含量之间呈极显著的线性正相关关系;与土壤的pH又有显著的线性负相关关系。

Seasonal Variability of Available Phosphorus in Farmland Soil of the Taihu Lake Region

Change of available phosphorus in soil profile of farmland soil (three main paddy soils: White soil, Huangni soil and Wushan soil) during wheat and rice growth was studied in the Taihu Lake region. The results were as follows: available phosphorus in soil profiles was gradually decreased from surface soil layer to bottom soil layer, was stable at about 45 cm, and then raised slightly near the groundwater. The available phosphorus content during wheat growth season (dry cultivation) and rice growth season (water cultivation) were higher than other seasons in a year. According to the analysis, the available phosphorus contents were significant related with soil organic matter. There was an exponential correlation between total phosphorus and available phosphorus in dry cultivation. When it in water cultivation, the correlation changed to linearity. The available phosphorus content was also influenced by pH value. Therefore, content of available phosphorus was affected by soil organic matter, total phosphorus and pH value in the Taihu Lake region.