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黄土高原不同立地条件下枯落物蓄积量及持水特征
1, 1,2, 1,2,3

(1.xibeinonglinkejidaxue yingyaappsuohuangtugaoyuanturangqinshiyuhandinongyeguojiazhongdianshiyanshi, shanxi yangling 712100; 2.zhongguokexueyuan shuilibu yingyaappsuo, shanxi yangling 712100; 3.zhongguokexueyuandaxue, beijing 100049)

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Variation of Litter Accumulation and Water Holding Capacity at Different Site Conditions in the Loess Plateau
ZHANG Huan1, MU Xingmin1,2, GAO Peng1,2,3

(1.state key laboratory of soil erosion and dryland farming on the loess plateau, northwest a&f university, yangling, shaanxi 712100, china; 2.institute of soil and water conservation, chinese academy of sciences and ministry of water resources, yangling, shaanxi 712100, china; 3.university of chinese academy of sciences, beijing 100049, china)

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备注

枯落物具有重要的水源涵养和拦蓄径流的功能,研究不同立地条件对枯落物蓄积量及水文功能的影响对于评价黄土高原生态恢复过程中枯落物的水土保持功能具有重要的意义。选择黄土高原典型植被带为调查样点,以不同立地条件下草本群落枯落物为研究对象,对枯落物的蓄积量及水文特征进行了相关研究。结果表明:(1)不同植被带枯落物蓄积量表现为森林带(154.25~392.95 g/m2)>森林草原带(151.27~287.58 g/m2)>草原带(109.24~174.81 g/m2),枯落物蓄积量总体表现为阴坡>阳坡,沟坡>梁坡;(2)不同立地条件下枯落物自然含水率、最大持水量、最大吸湿比均具有一定的差异性。森林带、森林草原带、草原带枯落物自然含水率的变化趋势分别为28%~54.5%,26.8%~41%和20.7%~31.3%,最大持水量分别为自身的3.26~3.64,2.94~3.2,1.63~1.92倍,最大吸湿比分别为3.26~3.64,2.94~3.21,2.63~2.92。(3)不同立地条件下枯落物持水量和浸水时间存在显著对数函数关系(R2>0.91),吸水速率和浸泡时间存在幂函数关系(R2>0.99);(4)枯落物有效拦蓄量表现为森林带(219.86~787.09 g/m2)>森林草原带(188.15~437.7 g/m2)>草原带(99.89~181.22 g/m2),表明森林带对径流拦蓄的贡献率最大,其次为森林草原带和草原带。立地条件对枯落物蓄积量和持水性能影响显著,研究结果可为科学评价黄土高原生态恢复过程中枯落物水土保持效益提供一定的理论依据。
Litter plays an important role in water conservation and runoff regulation, which has great significance for evaluating the water and soil conservation function of litter during the ecological restoration of the Loess Plateau. In order to investigate the properties of the litter layer of the herb communities, three typical vegetation zones were chosen at different site conditions in the Loess Plateau, and effect of litter on hydrological functioning was assessed. The results show that:(1)the litter accumulation in different vegetation zones decreased in the order: forest(154.25~392.95 g/m2)> forest-steppe(151.27~287.58 g/m2)> grassland(109.24~174.81 g/m2), and the litter accumulation in the shady slope was generally higher than that in the sunny slope, and higher on the gully slope than that on the ridge slope;(2)the natural moisture contents of litter in forest zone, forest-steppe zone and grassland zone were 28%~54.5%, 26.8%~41% and 20.7%~31.3%, respectively; the maximum water-holding capacities of litter were 3.26~3.64,2.94~3.2 and 1.63~1.92 times of litter mass, respectively, and the maximum moisture absorption ratios were 3.26~3.64, 2.94~3.21 and 2.63~2.92, respectively;(3)the relationship between the obtained values of water holding capacity and soaking time of litter followed the logarithmic function well(R2>0.91), and the relationship between the water absorption rate and soaking time could be described by power function well(R2>0.99);(4)the effective runoff interception of litter followed the order: forest(219.86~787.09 g/m2)>forest-steppe(188.15~437.7 g/m2)>grassland(99.89~181.22 g/m2), indicating that the forest zone had the largest contribution to runoff interception, followed by forest grassland and grassland. Overall, different site conditions had significant impacts on litter accumulation and water holding capacity.
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