岩溶山地不同土地利用土壤的水分特性差异

Differences of Soil Water Characteristics under Different Land Use Patterns in Karst Mountains

对北碚观音峡背斜岩溶低山不同土地利用方式下土壤的持水、供水、吸水和蒸发特征进行了研究。结果表明,土地利用方式的不同使低吸力段水分状况存在明显差异,样地1,7的供水性能较好,样地3和6持、供水能力都较好,样地9的持、供水性能差,样地4,10的持水性能较好但供水能力较差。样地2,3,5,9土壤比水容量达10-7数量级(ml/Pa·g)时在土水势-10～-30kPa范围开始出现,表明其土壤的保水供水性能相对弱;各样地土壤在土水势-30～-60kPa时比水容量达10-7数量级,表明岩溶山地土壤在脱水过程中,在还未达到理论上的BCM值时,实际就有可能因水分不足而对植物生长产生不利影响。通径分析表明,岩溶山地土壤的持水性能主要与有机质、>0.25mm水稳性团聚体有关,二者的效应大于粘粒的效应。

Studies on soil water holding capacity, soil water supplying capacity, soil water absorption and evaporation capacity under different land use patterns in the Guanyinxia anticlinal karst mountains showed that the differences of soil utilization styles change the soil water characters in the lowsuction stage obviously. Plot 1 and plot 7 have a superior soil watersupplying capacity; plot 3 and 6 has not only a superior soil water holding character but also a soil watersupplying capacity. Both the soil waterholding and soil watersupplying capacity of plot 9 are bad. Plot 4 and 10 have a good soil waterholding character s, but the soil watersupplying capacity is bad. The specific water capacity of plots (2,3,5,9) is lower than 1×10-6 ml/(Pa·g) when the soil water suction is in -10^-30 kPa range indicate their soil waterretention and soil watersupplying capacity are inferior than other plots. The specific water capacity of all other plots is lower than1×10-6 ml/(Pa·g) in -30^-60 kPa suction indicate that when the soil moisture contents are lower than theoretic BCM, it would take a disadvantage influence upon plant because of water deficiency in soil dewater processes in Karst mountain. Path analysis shows that the soil water holding capacity in Karst mountains is mainly correlated with organic matter, >0.25mm water stable aggregate, their effects are major than clay.