Aboveground biomass production and soil moisture characteristics of different herb communities in the Loess Hilly-gully Region

The objective of this study is to elucidate the biomass production and soil moisture characteristics of different herb communities at different succession stages in the Loess Hilly-gully Region on the Loess Plateau. After filed investigation and in situ observation,the aboveground biomass,soil moisture and their relationships of five different herbaceous communities( Stipa bungeana,Artemisia sacrorum,A. giraldii,Bothriochloa ischaemum,S. grandis) in Yanhe Watershed were analyzed. Results showed that: soil moisture contents of the five plant communities at different succession stages had obvious vertical distribution characteristics in 0- 500 cm soil profile,which decreased in 0- 50 cm layer, then increased in 50- 200 cm layer,and maintained stable in 200- 500 cm layer; aboveground biomass of plant communities showed an increase at early succession stages,reaching the peak at B. ischaemum stage( about 25 years after returning farmland), and decreased thereafter; there existed positive correlations between aboveground biomass and soil moisture,especially for that in 0- 200 cm soil layer;plant communities can make use of soil moisture in deeper layers over succession,showing a strong adaptation to environment.