Responses of aboveground and belowground net primary productivity to sand burial and enhanced precipitation in a semiarid desertified steppe

Abstract

AbstractSand burial and precipitation drive plant community structure and functions in semiarid desertified areas, while net primary productivity (NPP) is one of the most important indicators of plant community function. However, how NPP responds to sand burial in combination with changed precipitation regimes is still unclear. We conducted a field experiment with simultaneous sand burial and enhanced precipitation treatments to test the responses of both aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) in a semiarid desertified steppe in North China. The results showed that sand burial significantly affected the community ANPP but had no significant effects on the community BNPP. Sand burial increased the ANPP of rhizome grass and decreased the ANPP of perennial herbs, bunchgrass and annual herbs, with no significant effects on legume herbs, while enhanced precipitation did not significantly affect the community ANPP and BNPP or the ANPP of all five plant functional types (PFTs). Sand burial combined with enhanced precipitation mediated the vertical allocation of BNPP in the community. There are multiple significant relationships between the ANPP of different PFTs and the BNPP among the different soil layers. These findings will be conducive to understanding the consequences of grassland desertification under the background of climate change, with corresponding implications for grassland management and vegetation restoration in semiarid desertified areas.