| A comprehensive evaluation of yield traits and nutritional value of7forages was carriedout in artificial grassland planted on deteriorated grassland in Maqu county. Comparison wasmade between a natural grassland dominated by Poa pretense and Elymus dahuricus andseveral forage crops/pastures including cereals. The main nutrient index, hay yield, and heightwere measured and compared between the various varieties; Analysis of vegetationcharacteristics,diversity and soil physical and chemical properties, yielded the following results:(1) By gray correlation method,the order of nutrition evaluation was so, Medicagosativa.cv. Gannong No.1>Secale cereale>Vicia sativa>Elymus nutans>Medicago sativa.cv.Xinjiang daye>Avena sativa>natural grassland>Onobrychis viciaefolia. The evaluationresult was the same with actual yield of of forage dry matter.(2) The yield of the natural grassland was2882kg/hm2, which was lower than Secalecereale, Avena sativa, Elymus nutans, but was higher than r any of the4legume pastures.(3) In a natural grassland, soil bulk density and pH were lower than the artificial grasslandand―black beach "degraded grassland, and the water content was higher. After artificialgrassland planting the recovery, the―black beach‖degraded grassland recovered and the soilphysical properties and structure improved significantly.(4) Plantung artificial grassland could improve the degraded grassland’s soil organic matter,total N, and total K; With the increase of years since planting, the soil surface nutrients showeda very significant increase, but the available nutrients showed a decreasing trend. The artificialgrassland planting helped degraded grassland by restoring soil nutrients, and played a positiverole in the Ecological Restoration. Such plantings can be used as one of the effective measuresto restore degraded grassland ecosystem in Maqu deteriorated grassland(5) The dominant species in the natural grassland communities were Poa pratensis、Elymus dahuricus，the dominance index were:0.798、0.627; the oat plot had many weedsnotably Elsholtzia ciliate、Galium verum、Microulasik kimensis，the dominance index valueswere:0.204、0.142、0.082; Two years after planting Elymus nutans, the proportion ofproduction contributed by weeds accounted for more than6%of the total output. Land degradation on abandoned land is serious, Grassland degradation on abandoned farmlands hasled to a significant changing in plant community structure; meanwhile, the forage yield werereduced from839g/m2to62g/m2, the production capacity has been reduced, therefore ther areamust be closed and a grazing ban imposed.(6) Artificial grassland to invest primarily in early. Three grassland output input ratio indescending order: natural grassland> oat> Elymus grass, indicating that the economic benefitsof natural grassland highest. Therefore, in the course of grassland use of natural grasslandprotection should be given priority so as not to degenerate; For some severely degraded areasby planting annual/perennial artificial grassland, so as to achieve economic and ecologicalbenefits of unity. |
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