黄土丘陵小流域生态用水试验研究——气候和土地利用变化的影响
Experimental study on ecological water use in a gully catchment of the loess plateau: effects of climate and land use change
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摘要: 为探讨黄土高原地区的生态恢复,以半干旱黄土丘陵区安家沟小流域的气象、土壤水分、地形图和土地利用图(1982年和2002年)为源信息,分析了不同植被类型的蒸散量和生态用水量、流域生态用水量及其与气候和土地利用变化的关系。研究结果表明:(1)流域土地利用结构从1982-2002年间变化较大,农地(特别是梯田)增加较快,乔木林地急剧减少,主要表现为毁林、开荒和造田;(2)研究区内各种植被/土地利用类型的蒸散量和生态用水都极大地受控于气候(特别是降雨量)的影响,其年际差异较大;(3)不同植被/土地利用类型间的蒸散量和生态用水差异明显,在各个年份乔灌林的生态用水量均大于农作物和自然草地的蒸散量和生态用水量,但生态用水的差异程度小于蒸散量的差异程度;(4)以自然草地(即荒草地)为标准,农作物的蒸散量和自然草地接近,但乔灌林地的蒸散量和生态用水量均远高于自然草地,难于实现土壤水分平衡;(5)流域土地利用结构的变化(主要是强耗水植被的减少)减小了流域生态用水量,增强了流域的水分平衡能力。Abstract: Based on the data from the map of climate,soil water and land use(1982 and 2002)in Anjiagou catchment in the loess plateau,this paper studies the change of land use,the evapotranspiration,the ecological water use for the different plant species and the catchment,and its the correlation with the change of the climate and the land use. The results indicate that (1)the the structure of land use in Anjiagou catchment had significant change from 1982 to 2002. The cropland(especially the terraces)increases while the woodland decreases significantly because of the deforestation and the expansion of the waste-land;(2)The ecological water use for all the vegetation types is controlled by the climate,and had significant variability in the study period;(3)The evapotranspiration and the ecological water use for the woodland and the shrubland was higher than those for the cropland and the natural grassland;(4)The water consumption for cropland was close to that for the natural grassland,but the water consumption for the woodland and the shrubland was significantly higher than that for the natural grassland;And(5)the ecological water use in Anjiagou catchment decreased from 1982 to 2002 due to the decrease of the woodland,which had increased the water balance of the catchment.