成都平原区土壤速效磷时空变化特征

根据1982年173个样点和2002年117个样点的分析数据，利用地统计学方法和GIS技术对成都平原耕层（0～20cm）土壤速效磷含量的时空变异特征进行了研究。结果表明，成都平原耕层土壤样点间速效磷平均含量由1982年的7.1mg／kg增至2002年的14.3mg／kg，平均增加了103.40％。20年间由于受区域间农业管理措施、土地利用方式和土壤颗粒组成差异的影响，占平原耕地面积75.86％的土壤速效磷含量增加，且区域增加幅度呈由东向西逐渐降低的趋势。土壤速效磷含量与土壤颗粒组成的相关性分析表明，1982年土壤速效磷含量与土壤砂粒（2～0.02mm）之间呈极显著的负相关，与土壤粉粒（0.02～0.002mm）之间相关未达到显著水平，与土壤粘粒（〈0.002mm）之间呈显著正相关；2002年土壤速效磷含量与土壤砂粒之间呈显著的负相关，与土壤粉粒之间呈极显著正相关，与土壤粘粒之间相关未达到显著水平。

Temporal-Spatial Variability of Soil Available Phosphorus in Chengdu Plain

According to the analysis data of 173 sampling points in 1982 and 117 sampling points in 2002, the temporal-spatial variability of soil available phosphorus (SAP) of the topsoil(0~20 cm) in Chengdu Plain was expressed by spherical semi-variance model and the ordinary Kriging interpolated method. The results indicated that the average content of SAP changed from 7.1 mg/kg in 1982 to 14.3 mg/kg in 2002, with an increase of 103.40%. Influenced by the differences of agricultural management, the land use type and the soil granule contents during the past 20 years, SAP content of 75.86% of the plain area increased, respectively, which presented decreasing trend from the east to the west. The results of correlation analysis between SAP content and soil particle composition showed that, in 1982, there were highly significant negative correlation between the SAP and soil sand particle (20.02mm) content, and highly significant positive correlation between the SAP and soil clay particle(<0.002 mm), while no significant correlation between the SAP and soil silt particle(0.020.002mm). The case was different in 2002, SAP was significantly negatively correlated with soil sand particle content, and highly significantly positively correlated with soil silt particle content, while not significantly correlated with soil clay particle content.