Study On Techniques Of Vegetation Restoration On Degraded Warm Temperate Tussock In The Southeast Of Yunnan Province

The degraded warm temperate tussock(Eragrostis nigra and Potentila nepalense) was studied using the principle of grassland ecology and vegetation restoration ecology in southeast of Yunnan from 2002 to 2004.Quantity characters,biomass and quality of grassland vegetation were measured based on fencing,ploughing with reseeding,lacerate sward with reseeding,no-till with reseeding and fertilizing.After three years continuous observation and analysis,the results show that:1.Comparing with control,richness index of community and species diversity indexes of Margalef were increased significantly during three years by fencing. Diversity indexes of Menhiniek was increased significantly in the second and third years.Diversity indexes of Shannon-Weaver was increased significantly in the second year,but it was not significant in the third year.There was no significant difference on Pielou evenness index in the restoration processing of degraded pasture.2.Coverage of pasture was increased from 60%-70%(before fence)to 100% after fencing.The quantity characters and spatial characters of dominant species changed regularly,such as sward height was increased significantly,both Eragrostis nigra and Potentila nepalense was increased significantly and dominated upper synusia gradually.The density of Eragrostis nigra was decreased annually.3.Second years and third year after fencing,the total above-ground biomass, grass and forbs were increased significantly.The legume biomass after four months fencing was higher than those of control,sixteen months and twenty-eight months after fencing.After twenty-eight months fencing,the total biomass of pastures increased 4 times(comparing with control),and reached to 5.8 t/hm~2(DM).The weight rate of grass increased from 21%to 55%,forbs decreased from 76%to 43%, and legume decreased from 6%to 1%. 4.Compaering with fencing,fertilization treatment made the total above-ground biomass increased,but there was no significant difference between lacerate sward with fertilizing and no-till with fertilizing,Lacerate sward with fertilizing made the biomass of native grass increased.5.Among all reseeding treatments,only lacerate sward with reseeding made the total above-ground biomass increased comparing with fencing.Comparing with Lacerate sward and no-till,ploughing with mixed-sowing made the ratio of reseeding grass increased to total biomass of pasture.Under the condition of reseeding,the ratio of reseed legumes was increased significantly to total biomass of pasture by ploughing with mixed-sowing compared with no-till.Except no-till with fertilization, all other treatments improved the quality of pasture.