补播苜蓿对退化草地植物群落结构和生产力的影响途径

Mechanism of Reseeding Alfalfa Improving Productivity and Plant Community Structure of Degraded Grassland

近年来,紫花苜蓿(Medicago sativa L.)和黄花苜蓿(Medicago falcata L.)被广泛选作补播材料,用于修复退化草地。尽管研究表明二者的植物学特征存在差异,但鲜有人关注它们是否会通过不同的方式影响退化草地的生产力。为了探究二者对退化草地的修复效果是否存在差异,并确定影响补播地生产力的限制因素,本研究选取黄花苜蓿和紫花苜蓿作为补播种对退化草甸草原进行了补播,并在隔年对草地植被、土壤理化性质和微生物量进行监测。结果表明,两种苜蓿都可以显著增加退化草地生产力并改善土壤健康状况。然而,紫花苜蓿通过增加土壤铵态氮改变植被群落结构,其补播样地生产力也由土壤速效养分影响;黄花苜蓿通过增加土壤速效磷含量改变植被群落结构,其补播样地生产力由植被群落结构和土壤微生物量共同影响。初步结果表明,黄花苜蓿更适宜在养分贫瘠的退化草地进行补播。此外在选择紫花苜蓿补播时,可以适当施肥以提高补播成功率。

In recent years,Medicago sativa L.and Medicago falcata L.have been widely chosen as reseeding materials for the restoration of degraded grasslands.Although studies have shown differences in their botanical characteristics,little attention has been given to whether they would have differential effects on the restoration of degraded grasslands.In order to investigate whether there are differences in the productivity of M.sativa L.and M.falcata L.on degraded grasslands,and to determine the limiting factors for successful reseeding,this study selected M.sativa L.and M.falcata L.as reseeding species and conducted a monitoring of vegetation,soil physicochemical properties,and microbial biomass in the following year.The results showed that both alfalfa species significantly increased productivity and improved soil health of degraded grasslands.However,M.sativa L.altered the vegetation community structure by increasing soil ammonium nitrogen,and the productivity of the reseeding plots was influenced by soil available nutrients.M.falcata L.altered the vegetation community structure by increasing soil available phosphorus,and the productivity of the reseeding plots was influenced by both vegetation community structure and soil microbial biomass.Preliminary results suggested that M.falcata L.was more suitable for reseeding in nutrient-poor degraded grasslands.Additionally,when selecting M.falcata L.for reseeding,appropriate fertilization should be applied to improve the success rate of reseeding.