潋水河流域生态修复过程中土壤速效钾的时空变异

Temporal-Spatial Variability of Soil Available Potassium in Processing of Restorage Ecosystem in Lianshui Basin

采用基于GIS普通克里格法和概率克里格法分析江西潋水河流域土壤速效钾含量的时空变异特征。结果表明,潋水河流域样点间表层(0～30cm)土壤速效钾平均含量由1981年的(134 8±89 7)mg/kg降低到2002年的(131 9±97 6)mg/kg,平均降低了2 15%。尽管经过近21年的生态修复,样点间土壤速效钾平均含量总体上下降不多,但因土地利用和水土流失修复工程实施的差异,占流域面积60 63%的土壤速效钾含量减少,仅占39 37%的土壤速效钾含量增加。土壤速效钾含量分级统计表明,1981年速效钾含量水平在50～100mg/kg,100～150mg/kg,150～200mg/kg和>200mg/kg的土壤分别占流域面积的10 35%,75 31%,11 78%和2 56%,而2002年则相应为30 75%,49 31%,16 60%和3 31%。该流域土壤速效钾在≤100mg/kg,≤120mg/kg和>150mg/kg含量水平下的几何平均概率分别由1981年的0 453,0 566和0 327变为2002年的0 523,0 611和0 292。从贮量变化上看,21年间潋水河流域内表层土壤速效钾贮量从1981年的2 48×104t变为2002年的2 30×104t,下降了1875 35t。

The temporal-spatial variability of soil available potassium (SAK) content in the Lianshui Basin was expressed by the spatial analytic approaches such as ordinary kriging (OK) and probability kriging (PK) on the basis of the software ArcGIS Desktop 8.1. The average content of SAK, which changed from (134.8±89.7) mg/kg in 1981 to (131.9±97.6) mg/kg in 2002 with a decrease of 2.15%, has shown a decreasing tendency during 21 years. Although there was just a little decrease in the average content of SAK in the 21 years of ecosystem restoring, SAK content of 60.63% area in the basin was decreased and that of 39.37% was increased because of the discrepancy in the landuse and rebuilding project of soil and water loss. Based on the grading statistics of SAK content, the area of gradeⅢ(50.0～100.0 mg/kg ), grade Ⅳ(100.0～150.0 mg/kg), grade Ⅴ(150～200 mg/kg) and grade Ⅵ(>200 mg/kg) were 10.35%, 75.31%, 11.78% and 2.56% of the basin area in 1981, comparing to 30.75%, 49.31%, 16.60% and 3.31% in 2002, respectively. The research results of probability kriging showed that the geometric mean probability of SAK≤100 mg/kg, ≤120 mg/kg and >150 mg /kg were 0.453, 0.566 and 0.327 in 1981, comparing to 0.523, 0.611 and 0.292 in 2002, respectively. The storage of SAK in the Lianshui Basin changed from 2.48×10~4 t in 1981 to 2.30×10~4 t in 2002 with a decrease of 7.56% during 21 years.