Reseeding improved soil and plant characteristics of degraded alfalfa (Medicago sativa) grassland in loess hilly plateau region, China

Abstract

It is of great significance for the sustainable development and feed supply of animal husbandry in the hilly region of Loess Plateau to improve the degraded alfalfa grassland scientifically and reasonably. We studied the effects of reseeding gramineous grass on soil physicochemical properties, microbial biomass, plant community characteristics and community nutrients of degraded alfalfa grassland based on four treatments: no reseeding, reseeding Elymus dahuricus, reseeding Dactylis glomerata, and reseeding Leymus chinensis. Soil physicochemical properties and microbial biomass were improved after reseeding E. dahuricus, and above-ground biomass and community coverage were increased by >30% compared with those without reseeding. The reseeding of E. dahuricus benefited soil properties, plant community characteristics, and community nutrients more than reseeding of D. glomerata and L. chinensis. Furthermore, a structural equation model (SEM) was established based on the analysis and screening of related variables to analyze the influence factors of reseeding on soil and community and their interactions in degraded grassland system. The SEM results showed that reseeding had significant effects on plant community characteristics, plant community nutrients and soil characteristics (P < 0.001), but the degree of influence decreased in turn. The interaction between soil characteristics and plant community characteristics was 18.72% higher than that between soil characteristics and plant community nutrients. We recommend reseeding of E. dahuricus as suitable method to improve degraded alfalfa grassland in the loess hilly plateau region.