沙棘柔性坝影响下砒砂岩沟道土壤水分空间变异分析

根据典型砒砂岩区内蒙古鄂尔多斯准格尔旗境内植有沙棘柔性坝的东一支沟道与无任何植物的对比沟道的表层(0-30cm)土壤含水量数据,运用地统计学方法分析与探讨了沙棘对砒砂岩区小流域沟道土壤水分小尺度空间变异的影响。结果表明:沙棘可明显提高砒砂岩区小流域沟道土壤含水量;沙棘柔性坝沟道与对比沟道土壤含水量具有明显的空间变异特征,沙棘柔性坝沟道土壤含水量在1-6m变程内具有中等程度的空间自相关性,对比沟土壤含水量在1-5m变程内具有较高的空间自相关性;土壤含水量分数维值表明,沙棘柔性坝沟道土壤含水量的空间依赖性比对比沟的要弱些;沙棘对小尺度土壤水分空间分布格局及其异质性有显著影响。应当指出的是,虽然降雨是土壤含水量空间自相关与分布格局影响的主要因素,但干旱条件也不容忽视,在长时间地表蒸发及植物蒸腾作用下,沟床表层土壤含水量空间变异性会进一步加强,且在一定程度上会影响沟床表层短根系及一年生草本植物的生长与分布。

Effects of the seabuckthorn flexible dam on spatial variation of soil moisture in the Pisha Sandstone Gully

Based on soil moisture content data in the top 0-30cm of the soil profile in the east-one-branch gully bed with the seabuckthorn flexible dam and non-vegetated gully bed(i.e.the contrasting gully bed without any kind of vegetation) located in Zhun-ge-er county,Erdos city,Inner Mongolia Autonomous Region.The effects of the seabuckthorn plant on spatial small-scale variation of soil moisture in the small catchment gully in the typical Pisha sandstone area were analyzed and discussed using the geostatistical method.The results showed that: 1) A remarkble increase of soil moisture content was found in the small catchment gully in the Pisha sandstone area due to the seabuckthorn plant;2) Spatial variation characteristics of soil moisture content were apparently found in both the gully with the seabuckthorn flexible dam and the control gully,and the soil moisture content distribution had obvious medium spatial autocorrelation properties at a range of 1-6m,while the spatial autocorrelation of soil moisture was quite higher in the control gully bed at a range of 1-5m;3) It was suggested that the spatial dependence of soil moisture content in the gully with the seabuckthorn flexible dam was weaker than that of the control by the comparison of the fractal dimension values of soil moisture in both the gullies;4) The seabuckthorn plant had a significant impact on the spatial distribution and heterogeneity of soil moisture at the top soil on a small scale.It should be pointed out that although precipitation was the major influencing factor of spatial autocorrelation and distribution pattern of soil moisture,the dry condition can not be ignored,because spatial variation of soil moisture content in top soil of the gully bed would be increased further and to some degree,the growth and spatial distribution of both short roots and annual herbage in gully bed would be affected under the long time surface evaporation and plant transpiration conditions.