The Study Of Spatial Distribution On Aboveground Biomass Of Grassland In Weibei Upland

The grassland community of natural grassland and improved grassland in weibei uplandwas investigated with the method of “aboveground biomass”. Combining with the gammadistribution model, we analyzed effects of reseeding on nutrition,aboveground biomass and itsspatial distribution from the view of spatial heterogeneity, hence we might provide atheoretical basis for recovering and increasing the productivity of degraded grasslands.The main conclusions obtained are as follows:(1) The density function of aboveground biomass at natural grassland and improvedgrassland fit the gamma distribution model very well.Therefore, the gamma distributionmodel can be used to study spatial heterogeneity of grasslands.(2) According to the study, we can concluded that the total biomass in improvedgrassland was higher than that in natural grassland, but the total number of species and Spatialheterogeneity of community were lower than that in natural grassland. The average biomassof improved grassland was Significantly higher than that of natural grassland (P <0.01), whilethe average number of species and species diversity index average was significantly lowerthan that of natural grass (P <0.01).The crude protein, crude fat, crude ash and crude fibercontent of improved grassland were higher than that of natural grassland,while thenitrogen-free extract content was lower than that of natural grassland, and the content of crudeprotein, crude fat and nitrogen-free extract were significant difference between improvedgrassland and natural grassland (P<0.05). There was a negative correlation between thespatial heterogeneity and aboveground biomass. The average biomass increased along withincrease of the number of species under improved grassland,but the average biomassdecreased along with increase of the number of species under natural grassland. Overall,thevariation coefficient on nutrition of improved grassland was higher than that of naturalgrassland, and there were also great differences between different nutrients in the samegrassland.