Evaluation to ecological water requirement of dry land system based on ecological function zones in Yanhe watershed

In this research, by taking dry land system of Yanhe watershed as an example, we selected the index with ecology and hydrology meaning and applied the RS, GIS and GPS technologies to establish the ecological function zones. At the same time, we assessed and analyzed the ecological water requirement and its distribution characteristics at the scales of vegetation-soil landscapes and ecological function zones. The results showed that Yanhe watershed could be divided into five ecological zones, which were sand fixation zone, drought defense zone, land and water maintenance zone, farmland planting zone and vegetation protection zone, respectively. The ecological water requirement of forest-cohesive loam was the most amount with 502.31 mm/a; while that of grassland-sandy loam was the least amount with 300.01 mm/a. The ecological water requirement of vegetation protection zone was the most amount with 357.72 mm/a; while that of drought defense zone was the least amount with 304.73 mm/a. This research offers scientific references for optimal allocation and sustainable utilization of land-water resources, and it is significant for ecosystem management.