【摘要】 土壤水分是黄土丘陵区植被成活与正常生长的关键因素。对黄土丘陵区不同生长年限小叶锦鸡儿灌丛及其撂荒地土壤水分的动态监测表明,随种植年限延长,小叶锦鸡儿灌丛下土壤水分含量呈持续下降趋势,40年灌丛下土壤含水量明显低于20年和10年的小叶锦鸡儿灌丛,且所有种植年限的灌丛土壤含水量均低于撂荒地。从周年内土壤水分季节变化看,整体呈下降趋势,4~6月不断降低,6~7月达到最低值,8~10月逐渐回升。对0~200cm土体剖面土壤水分分布研究表明,随种植年限增加,小叶锦鸡儿灌丛各深度土层土壤含水量呈递减趋势,在40~80cm土层随种植年限增加土壤含水量减少幅度明显。整个生长季各年限灌丛的土壤水分循环水平不高,40年灌丛只有4.63%,与撂荒地比较相差2.92%,而各年限灌丛土壤水分表观平衡均表现为亏缺状态。表明目前黄土丘陵区人工种植的小叶锦鸡儿灌丛土壤水分环境不容乐观,长期处于水分胁迫状态,不利于其生存生长,存在灌丛衰退甚至死亡的风险。更多还原

【Abstract】 Soil moisture is a key factor for the growth and survival of vegetation in the loess hilly region. Soil moisture dynamics was monitored under artificial Caragana microphylla shrub at 5 ages (5, 10, 20, 30 and 40 years after germination) in the loess hilly region of Northwest Shanxi Province in 2006. The results show decreasing soil moisture content (SMC) under artificial C. microphylla shrub with increasing age. SMC is lowest under the 40-year shrub. SMC under the shrubs is generally lower than under nearby wastelands. Based on monthly trend, SMC gradually decreases from April to June (hitting the lowest point in June), and then gradually increases from August to October. Vertically, SMC in the 0~200 cm soil layer gradually decreases with soil depth, especially in the 40~80 cm soil layer. During shrub growth period, soil moisture circulation is low. It is only 4.63% under the 40-year shrub, which is 2.92% less than that under nearby wastelands. Furthermore, the overall soil moisture balance is negative. It then implies that the artificial C. microphylla shrub is under moisture stress in the loess hilly region. In the long-term, moisture stress could threaten the growth and survival of artificial C. microphylla shrubs in this region.更多还原