Relationship Between Plant Diversity And Productivity In Fenced Mowing And Grazing Meadows Of Songnen Plain

Overgrazing and excessive mowing can lead to grassland degradation. The degraded grassland restoration theories and technologies were important questions in grassland management and grassland ecological research in our country. Our study set sample plots in Changling mowing grassland (fencing 4 years) and Tongyu grazing land(fencing 10 years and 6 years) in Songnen meadows; conducted sampling surveys and soil core sampling; community characteristics, belowground biomass and belowground productivity in 2009 and 2010. The purpose is to illuminate the relationship of plant diversity, aboveground productivity, belowground productivity. Our study could provide reference for Songnen plains degraded grassland restoration theoretical research and technologies application.Results showed that, at mowing grassland in 2009, species richness and aboveground biomass had no significant differences between fencing and mowing plots, however, belowground biomass in fencing plot was significantly higher than belowground biomass in mowing plot. Both aboveground biomass and belowground biomass decreased with species richness increase and inclined to negative relationships. In 2010, belowground productivity in fencing plot was significantly higher than that in mowing plot. The differences among plant species richness, aboveground biomass and belowground biomass in fencing and mowing plot had no statistically significant. There was a negative relationship between aboveground biomass and plant diversity. During The two years experiment, we found that there was no significant correlation between aboveground biomass, belowground biomass and plant diversity. Over the first four years following fence, aboveground biomass and belowground productivity increased significantly, however, species diversity and the relationship between diversity and productivity had no significant changed.In 2009, Plant aboveground biomass of the plots with 9 years fenced was significant lower than the plots with 6 years fenced. The plant aboveground biomass was increased with species richness increase at two difference fenced grassland plots. In 2010, for two 10th and 6th year plots, species richness had no significant difference, While both plant aboveground and belowground biomass were increased with species richness increase. Since the grazing land fenced from 6 to 10 years, the relationship between belowground biomass and species richness had significant positive lineal correlation. Meanwhile, the relationship between species richness and productivity had no significant change.