黄土高原地区森林植被生态需水研究

水土流失是黄土高原面临的主要生态问题,而退耕还林还草、恢复植被是治理水土流失、改善生态环境的必然选择.但黄土高原位于干旱半干旱地区,水资源匮乏是影响该地区植被生态建设的根本因子.因此,植被生态需水研究对于该地区的生态环境建设具有极其重要的意义.本文根据最新遥感图像资料,在GIS支持下,计算了黄土高原地区现有林地生长季的最小生态需水量和适宜生态需水量,其结果分别为262.49×10⁸ m³和421.34×10⁸ m³.除去降雨对林地耗水的补给外,以最小生态需水量为标准,则黄土高原地区在生长季发生水分亏缺的林地面积为7 639.09 km²,占现有林地总面积的9.1%,亏缺水量为4.77×10⁸ m³;以适宜生态需水量为标准,则有57.7%的现有林地在生长季中发生水分亏缺,亏缺水量为58.55×10⁸ m³.

Ecological Water Requirement of Forests in Loess Plateau

Converting degraded farmlands to forest or grass lands is the best approach to reduce the soil erosion, the Loess Plateau is faced with most serious ecological disaster. Loess Plateau located in the arid and semi-arid regions is a fragile region with the characteristics of little precipitation and intensive evapotranspiration. Therefore, water is the most important factor limiting the eco-restoration and construction of the vegetation in the region.According to the latest digital land use map and with GIS,the ecological water requirement for forests in Loess Plateau was estimated,and by the water balance of the forest ecosystem in their growing season,the ecological water shortage was calculated.The results revealed that the minimum and suitable ecological water requirement of the forests in Loess Plateau were approximately 262.49×10⁸ m³ and 421.34×10⁸ m³ respectively.Accordingly,if it is taken the minimum ecological water requirement as the quota,the area of forests suffered water shortage was about 7.639.09 km³, 9.1% of all,and the ecological water shortage was amounted to 4.77×10⁸ m³;if it is taken the suitable ecological water requirement as the quota, the forest land area suffered water shortage was about 57.7% of all, and the ecological water shortage was roughly 58.55×10⁸ m³.