Natural grasslands maintain soil water sustainability better than planted grasslands in arid areas

Abstract

Planted grassland is one of the most quickly and effective way for vegetation restoration in arid and semi-arid regions. However, inappropriate grasslands construction can cause soil water deficit and soil drying in arid areas. In the present study, we evaluated the soil water storage deficit and soil water balance characteristics of different grassland types under natural conditions. The relative growth rates of planted grasslands, especially the planted legume grasslands, were approximately double higher than that of the natural grassland. Soil water storage deficit degree was the highest in the 0–50 cm soil layers than below the 50 cm layers. Soil water deficit degree was higher in legume grasslands than in gramineous grasslands below the depth of 50 cm, and it was significantly lower in the natural grassland than in planted grasslands below the depth of 200 cm (P < 0.05). The precipitation (P) was lower than the evapotranspiration (ET) in planted grasslands, thus resulting in soil water deficiency and soil desiccation. The average ET/P value was significantly higher in planted grasslands than in the natural grassland, and followed the order of planted gramineous grasslands> planted legume grassland and shrubland > natural grassland. None of the grasslands got sufficient water supply during the growing season for transpiration and growth. Our findings provided evidence that natural grasslands have lower water consumption, and indicated which vegetation types can maintain more soil water and facilitate vegetation sustainability when undertaking restoration in water-limited environments.