Effects of ridge and furrow rainwater harvesting system with gravel mulch on growth of sea buckthorn

In order to understand the role of ridge and furrow rainwater harvesting (RFRH) system with gravel mulch for the eco-environmental projection and recovery in the cold and semi-arid areas of high plateau, a field study was conducted to investigate the effect of RFRH system with gravel mulch on the growth of sea buckthorn in Lake Qinghai Watershed. It showed that the average runoff efficiency was 62%、33%、23% for the plastic-covered ridge (narrow), uncovered ridge (narrow) and flat land after the runoff was produced at the experimental site in 2009, respectively. The survival rate of sea buckthorn for RFRH system with gravel mulch was 49%, 27% higher than the flat land, while it was also higher for narrow ridge (59%) than for wide ridge (40%) in the same conditions. In the contrary, the survival rate of sea buckthorn for plastic-covered ridge and gravel-covered furrow was low. Compared with the flat land, RFRH system with gravel mulch could accelerate the growth of sea buckthorn significantly, but too much water in the furrow may restrain the growth of sea buckthorn, in the case of wide ridge with gravel mulch in a wet year. Because of the interaction between the interception loss of precipitation and soil moisture conservation by mulch, the effect of RFRH system with gravel mulch on leaf water potential was not obvious during light rainfall events. In summary, RFRH system with gravel mulch could accelerate the survival and growth of sea buckthorn, but it is essential to determine appropriate measures of RFRH system based on the precipitation properties and vegetation water requirements.