太湖地区典型水稻土大时间尺度下的肥力质量演变

2004年通过调查与第2次土壤普查(1982年)相对应地块的土壤性状,对太湖流域江苏省武进地区典型水稻土土壤肥力变化趋势及原因进行分析.结果表明:从1982年到2004年,该研究区主要的6类水稻土共198个取样点的有机质、全氮、速效磷、速效钾显著上升,而pH和CEC显著下降.各亚类水稻土,除小粉土和沙土肥力质量指数有较大幅度提高外,其他类型水稻土肥力质量指数增加不大.各亚类水稻土土壤肥力单因子质量指数变化趋向一致,即1982年各亚类土壤速效钾的单因子质量为最低,其中速效钾单质量指数最小的小粉土为1.48;2004年pH值的质量指数则为最小值,其中pH质量指数最小的白土仅为1.73;同时,各水稻土CEC单质量指数由第2次土壤普查时的2.91～3.0显著下降为2004年的2.14～2.93.因此土壤酸化并伴随盐基离子的淋失是限制研究区水稻土土壤肥力质量的关键因素.

Response of typical paddy soil fertility to long-term cultivation in Taihu Lake Region

The chemical properties of collected soil samples (2004) were compared with that of the Second National Soil Survey (1982) to analyze changes in soil fertility in Wujin, Taihu Lake Region of Jiangsu Province. The results show that of all the six sub-soil varieties of paddy soil collected from 198 sampling sites, the average content of soil total nitrogen, organic matter, available phosphorous and potassium has significantly increased from 1982 to 2004. That of soil pH and CEC (cation exchange capacity) has decreased during the same period. The soil fertility indices of the six paddy sub-soil varieties are largely the same, except for silty and sandy soils. A single factor soil fertility index for all the sub-soil varieties have a similar trend, i.e. available potassium and pH are the lowest single factor soil fertility indices for 1982 and 2004 respectively. White soil has the lowest pH fertility index (1.73). CEC fertility index has decreased from 2.91 ~ 3.0 of the Second National Soil Survey to 2.14 ~ 2.93 of 2004 collected samples. This indicates that the major restricting factor for soil fertility in this region is low soil pH and loss of exchangeable base anions.