Controlling gully- and revegetation-induced dried soil layers across a slope-gully system

The Effect of Robinia pseudoacacia Plantation on Soil Desiccation across Different Precipitation Zones of the Loess Plateau, China

Ecological restoration has increased vegetation cover and reduced soil erosion, but it has also resulted in decreased soil-moisture content (SMC) and increased soil desiccation, which has ultimately led to a weakening of the “soil reservoir” function and a decline in the growth of plantations. Thus, soil desiccation has been a serious threat to the sustainable utilization of soil water resources and vegetation rehabilitation. In this study, the soil moisture of a Robinia pseudoacacia forest as well as its corresponding soil desiccation to a depth of 500 cm were measured across three different precipitation zones (400–450, 500–550 and 550–600 mm) along a north–south transect on the Loess Plateau. The results showed that the soil-moisture environment and soil desiccation status generally improved with the increasing precipitation gradient, while soil-moisture over-consumption significantly declined (p < 0.05). However, due to the elder forest-stand age and severe growth recession, the soil desiccation of R. pseudoacacia in the northern part was less than that in central zones. As the forest-stand age increased, SMC of R. pseudoacacia increased firstly and then decreased, and both soil-moisture consumption and the average soil desiccation rate peaked in the RP-5a, showing no significant consistence with forest-stand age. Therefore, understanding the soil-moisture status of forestland may better provide scientific basis for native vegetation restoration and reconstruction in water-limited regions.