Screening Of High Quality Pasture And Effect Of Soil Improvement In Coal Mining Subsidence Area

In order to explore the new utilization model of soil reclamation and the reclamation effect of biological improvement in coal mining subsidence area,the experiment was conducted in the coal mining subsidence area of Xiaoyi City,Shanxi Province.Four grass species(Bromus inermis.,Pennisetum alopecuroides.,Elymus sibiricus.,Elymus breviaristatus.)and four legume species(Medicago sativa.,Onobrychis viciaefolia.,Astragalus adsurgens.,Trifolium pretenser.)was selected to study on production performance and nutritive value of eight herbage species and dynamic changes of soil nutrients for obtaining theoretical basis for soil improvement in coal mining subsidence area.The results showed :1.The fresh and dry grass yield of Bromus inermis were 12.56 t/hm2 and 4.91 t/hm2 respectively after two years of planting in the coal-mining subsidence area,which were significantly higher than those of Pennisetum alopecuroides and Elymus breviaristatus(P<0.01).The yield of fresh and Hay of Astragalus adsurgens were 36.35t/hm2 and 9.06t/hm2 respectively,which was significantly higher than that of Medicago sativa.and Trifolium pretens(P<0.01).2.The results of nutritional components analysis are as follows: In four grass species the ADF(28.88%)and NDF(59.44%)of Bromus inermis are the lowest,but WSC(8.56%)and RFV(104.67)is the highest.In four grass species Elymus breviaristatus has the highest EE(4.01%)and P(0.22%),Elymus sibiricus has the highest CP(9.20%)and Ca(1.10%).The Ash(11.38%)of Pennisetum alopecuroides is the highest in four grass species.Among four legume species the ADF content(22.62%)and the NDF content(39.72%)of Astragalus adsurgens were the lowest,but EE(3.41%)and RFV(170.18)is the highest.Medicago sativa is the highest in the content of P(0.20%)and CP(14.50%).The content of Ca(1.10%)and WSC(6.74%)for Onobrychis viciaefolia is the highest in four legume species.The content of Ash(9.39%)of Trifolium pretense is the highest among four legume species.3.The soil nutrient content for 8 herbage species in coal mining subsidence area increased with the increase of forage planting time,and decreased with the deepening of soil tillage layer.The highest content of 0-10 cm soil NH4+-N?NO3--N?alkali-hydrolyzed nitrogen of Astragalus adsurgens was increased by154%,147%,112%.The highest content of organic matter and N:P was found in Trifolium pretense in0-10 cm soil(62%,61%),and the highest increase in available phosphorus content(P)was Elymus sibiricus in 0-10 cm soil,It is 44%.The results show that monoculture can promote soil improvement in coal mining subsidence areas.4.The yield and quality of herbage were analyzed by grey correlation analysis.Finally,the high quality forage grass was screened out.Medicago sativa WL168 HQ and Astragalus adsurgens suitable for local mining areas.