中亚热带杉木人工林林下植被生物量对增温和隔离降雨交互作用的响应

In order to determine the interaction effects of soil warming and precipitation separation on undergrowth vegetation biomass in Chinese fir (cunninghamia lanceolate) plantation, soil warming(W, +5℃ above the ambient temperature of the control)、50% precipitation separation (P)、the interaction effects of soil warming and precipitation separation (WP) and control (CT) were set up in the wild. There were four treatments, and each processing was five repeats. After three months of research, the result showed: soil warming、precipitation separation and their interaction have a significance effect on undergrowth vegetation biomass in Chinese fir plantation: (1) The biomass increased evidently in the treatments of W and WP, and the degree of increased under W treatment is much more than WP treatment. (2) But the P treatment significantly decreased vegetation biomass; (3) Root-canopy ratio also decreased in the treatments of W、P and WP. (4) The change of under forest vegetation biomass and Root-canopy ratio were caused by the increase of soil temperature primarily. However, the change of dissolved carbon、dissolved nitrogen and mineral element concentration of soil solution directly caused the change of different parts of biomass. A significant increase in the biomass of different part of the undergrowth vegetation biomass in Chinese fir plantation in the warming treatment were mainly caused by the decrease of the concentration of Al3+, Fe3+ and Ca2+. And the increase of the concentration of Al3+ and Na+ were the cause of the decrease of the biomass of the underground part of vegetation after precipitation separation. Furthermore, the significant increase of Al3+, Fe3+, K+, Ca2+, Na+ and Mg2+ was the reason that the biomass of different parts of undergrowth vegetation biomass was affected by the interaction between warming and precipitation separation by two factors alone.