作 者 ：陈杰,刘文兆*,张勋昌,侯喜禄,胡梦珺,王兵2
期 刊 ：生态学报 2008年 28卷 7期 页码：2954~2963
Keywords:loess hilly-gullied region, woodland, soil and water conservation, soil water content,
摘 要 ：根据安塞水土保持试验站1993～2002年林地径流小区的降雨产流产沙的定位观测资料及2002年土壤含水量资料，分析了不同树种对坡面尺度降雨产流产沙及土壤水分的影响。结果表明：场降雨径流小区的产流量、产沙量与降雨量具有较好的相关性；多元回归分析表明，场降雨产流量和产沙量与降雨量和最大30 min 雨强的乘积呈正相关，与植被覆盖度呈负相关，场降雨产沙量回归方程复相关系数为0.253，各处理场降雨产流量回归方程复相关系数的变化范围为0.465～0.723，均达到了极显著的水平（P＜0.01）。同时，各树种均具有良好的减流减沙功能，与农地相比，年均产流量和产沙量分别减少4.8%～52.9%和26.8%～86.0%；沙棘纯林及其混交林的减流减沙效益优于油松纯林。同时，沙棘纯林及其各混交林在造林初期就表现出良好的减流减沙效益，随着树龄的增长，其作用更加明显；而油松纯林在造林初期作用不明显，甚至出现产流量和产沙量大于农地的现象，但随着树龄的增长，减流减沙作用逐渐呈现并增大。沙棘纯林及其混交林30 cm 以下土壤含水量在整个生长季中均呈递减趋势，生长季初（4月份）土壤含水量最高，而生长季末（10月份）降到最低值。2002年沙棘纯林的耗水深度为220 cm，而其混交林的耗水深度达到300 cm。同时，在整个生长季节中，沙棘纯林及其混交林整个剖面平均土壤含水量存在着显著的差异，表现为：沙棘×杨树＜沙棘＜沙棘×油松。
Abstract:Soil and water conservation benefits of different afforested trees in the loess hilly-gullied region were evaluated based on runoff and soil erosion measured in vegetated runoff plots between 1993 and 2002. Soil water conditions and their dynamics under forestation trees were also analyzed according to soil water content measured in 2002. Results showed that runoff and sediment were correlated with rainfall. Multiple regression analysis indicated that there was a positive correlation between runoff and the product of rainfall depth and maximum 0.5-hour rainfall intensity at the significant level of 0.01, as well as between sediment and the product of rainfall depth and maximum 0.5-hour rainfall intensity. However, both runoff and sediment were negatively correlated with vegetation cover. The multiple correlation coefficient ranged from 0.465 to 0723 for runoff and was 0.253 for sediment. In addition, soil and water conservation benefits were reasonably evident for all afforested trees. Compared with farmland, runoff and sediment decreased to 4.8%-52.9% and 26.8%-860%, respectively. The soil and water conservation benefits of Hippophae rhamnoides and its mixtures were greater than those of Pinus tabulaeformis whose cover was poor in the early growth years, during which runoff and sediment were even greater than those of farmland. But the benefits increased as the trees grew. However, the soil and water conservation benefits of Hippophae rhamnoides and its mixtures were good even in the early growing years and became even better as trees grew over time in eleven years. Soil water content below 30 cm soil layer under the Hippophae rhamnoides and its mixtures decreased during the entire growing season, being highest in April and lowest in October. Water consumption depths of the Hippophae rhamnoides under monoculture and biculture were 220 and 300 cm, respectively, in 2002. There were significant differences in soil water content for mono-species of Hippophae rhamnoides and its binary mixtures during the entire growing season. The tree species, in terms of soil water content, ranked in the ascendant order of Hippophae rhamnoides-Populus simonii Carr mixture, Hippophae rhamnoides, and Hippophae rhamnoides-Pinus tabulaeformis mixture.
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