Vegetation Characteristics And Production Benefit Of Grass/Trifolium Repens Grasslands Under Rotation Improvement Model

Grass/Trifolium repens sowing can make the degradation grassland recovering and its economic benefit improvement.The previous researches focus on the nutrients,fertilization and vegetation components of grasslands.The grasslands cultivated mostly by direct seeding and least by livestock night penning,but the studies of grassland sowing with rotation improvement were rarely reported.We analyzed the vegetation characteristics(included the height of community,coverage,species,the height of species,density and biomass),grass and soil nutrients(included organic matter,total N,total P),and economic benefit in Yunnan sheep breeding farm.Which will help us to explore the suitable sowing model of grass/Trifolium repens grasslands in karst area,south China.The results are as follow:(1)The dominant species in the rotation improved grassland(RI)was Dactylis glomerate,the subdominant species were Trifolium repens and Eragrostis nigra,the main companion species were Galinsoga parviflora,Veronica arvensis and Lolium perenne.The dominant species in the conventional improved grassland(CI)was Dactylis glomerate and Artemisia argyi,the subdominant species were Trifolium repens and Eragrostis nigra,the main companion species were Stellaria vestita and Galium aparine var.tenerum.(2)Species richness index was RI(29 species)>CI(23 species),and Simpson index was RI(0.496)<CI(0.690).In rotation improved grasslandS,Dactylis glomerate,Lolium perenne and Eragrostis nigra have more tillers,so the grasslands were more stable.The biomass of unseeded grasses was CI(19.4%)>RI(13.2%).(3)The grassland sowing method had no influence on the total N of soil and root.The organic matter of soil was RI(6.55%)>CI(5.17%),and the total N of dead matter and living matter was RI(1.30% and 2.06%)>CI(0.85% and 1.62%).(4)In conventional improvement grasslands,57.3%,56.6% and 47.2% of Dactylis glomerate,Eragrostis nigra and Lolium perenne tillers were respectively concentrated in 0~35,0~35 and 0~10 tillers/plant.In rotation improvement grasslands,38.4%,37.5% and 45.5% of Dactylis glomerate,Eragrostis nigra and Lolium perenne tillers were respectively concentrated in 36~70,36~70 and 21~30 tillers/plant.The seedling reserve of three species in the two improved grasslands were rich,while the growth status of the adult plants was good,both belonging to relatively stable growth populations,and the rotation improvement grasslands was relatively more stable.To Vicia villosa + silage corn + grass/Trifolium sowing model can improve economic benefit and soil fertility of grasslands.This model is an effective method for improving natural pasture and degraded grasslands in karst mountain areas,south China.