The Study On Vegetation Restoration For Heavily Degarded Subalpine Meadow In Different Cultivation Measures

Grassland degradation has become a key factor that limits the development of grasslandanimal husbandry productivity, which is prevalent in different pastoral areas. Therefore,pasture cultivation is a valid measure to suppress and avoid grassland degradation. Gannangrassland, as the most important pastoral area of Gansu Province, degraded seriously.In present paper, degraded subalpine meadow, located in Dianzi township, Lintan county ofGannan city, was selected as the research object to analyze the effect of different cultivationmeasures (sward ripping, phosphate fertilizer application and reseeding) on grasslanddegradation compared with natural pasture (control) from2011to2012. The experimentcomposed of seven treatments, namely phosphate fertilizer application (P), sward ripping (S),reseeding (R), S+P, S+R, P+R, S+P+R. Meanwhile, the seeds of alfalfa (Medicago sativaL.), drooping wildryegrass (Elymus nutans) and siborian wildrye (Elymus sibiricus) were usedfor reseeding separately or mixedly. Utilizing comprehensive evaluation of grasslandvegetation and evaluation of plant diversity index was used to classify the level of forageplants and functional group, and investigate the effect of vegetation restoration for degradedgrassland. The results were obtained as follows.1. The aboveground biomass, height and coverage of excellent forage, good forage andpoisonous forage showed a gradual increase trend while that of mediate forage presented anodd peak curve.2. Reseeding can significantly improved the aboveground biomass of excellent forage andgood forage. However, sward ripping was superior to reseeding and R+P, which played animportant role in promoting the aboveground biomass of good forage. The abovegroundbiomass of sward ripping and S+P was significantly higher than reseeding and R+P, andphosphate fertilizer application promoted the aboveground biomass of mediate forage.3. Sward ripping and reseeding decreased the height of mediate forage while phosphatefertilizer application increased significantly that of good, mediate and poisonous forage.Besides, reseeding improved the height of excellent and good forage.4. Sward ripping increased the coverage of good forage while reseeding improved that ofexcellent and good forage, and the effect of reseeding and R+P was inferior to that of sward ripping and S+P. Phosphate fertilizer application had an a positive impact on the coverage ofgood, mediate and poisonous forage while other treatments decreased the coverage of mediateand poisonous forage in some degree.5. In the soil depth of0-10cm, different cultivation measures promoted the growth anddevelopment of root and decreased root shoot ratio.6. The species richness of R+P and R+S+P improved while that of sward ripping reduced.7. Reseeding improved the importance value of excellent and good forage, and it had nosignificant impact on the dominant position of grassland vegetation communities. However,sward ripping and S+P significantly increased the importance value of good forage, andchanged the pattern of grassland vegetation, achieving that good forage was the dominantposition of grassland vegetation communities.8. Reseeding and sward ripping improved the Shannon-Wiener diversity index of excellentand good forage, respectively. Compared with control, different cultivation measures reducedthe Shannon-Wiener diversity index of poisonous forage and contributed to development ofother functional groups. Meanwhile, phosphate fertilizer application reduced theShannon-Wiener diversity index sum of functional groups while other treatments improvedthat. In addition to phosphate fertilizer application, other treatments were conductive tostabilize forage communities.