Studies On Effect Of Herbicide And Fertilizing To Artificial Grassland's Production Characteristics And Community Stability In Qing-hai Alpine District

In Qinghai-Tibet Plateau areas, mixed perennial grassland is the best choice to raise productivity, maintain the ecological balance. But by the constraints of environmental factors, it is difficult to maintain production and ecological stability. For this reason, the study on practices for the productivity and stability of artificial grassland was carried out on the black soil type of degradation grassland area at the altitude 3760 m, the average annual temperature -3.9℃, the annual precipitation of 513.2 mm in alpine regions– Gemlatan, Maqin County of Qinghai Province. The results showed that:1. The grasses both from the treatment group and control group could not complete the full growth stages in first year and the dates of each growth stage were basically the same. In second year, the grasses re-greened in late April, and the grasses in treatment group could complete all growth stages, however, 30% to 50% of grasses in control group could not complete the whole growth stage. This mean that the practices could improve the grass growth.2. The height, coverage and biomass in treatment group were higher than that of the control group. The practices could effectively enhance the coverage and productivity of high quality grasses.3. Elymus nutans and Festuca sinensis cv. Qinghai were the dominant components in community. Ten mixed communities could be divided into two categories: Elymus nutans community and Festuca sinensis cv Qinghai + Elymus nutans community.4. The growth rate of communities showed an inverted"V"pattern. it was 0.65 cm/d to 0.70cm/d in treatment group and 0.55 cm/d to 0.65cm/d in control group respectively.5. Both stability and the rate of leaf to stem in treatment group were higher that those in control group. The community biomass of treatment was mainly distributed within 0 to 30cm, and its layer structure was a significant "pyramid" type.6. Species diversity and richness of treatment group were lower than that of control group.7. The contents of crude protein in treatment group was increased and the content of crude fiber was decreased at the same time. 8. The dominance and inter-species RYT value indicated that components of community were constantly changing in the first two years, but the dominant species remained unchanged; mixed artificial community could be divided into two types: unstable type and stable type.9. The benefit of treatment group was greatly higher than that of control and it was same for the ecological benefit.In general, the practices used in treatment group were proper for sustainable utilization of artificial grassland on Qinghai-Tibetan Plateau in future.