Effects of soil moisture and AM fungi on the soil physicochemical property in the rhizosphere of Astragalus adsurgens

Astragalus adsurgens Pall.is an excellent grass and sand-fixing plant.Our objective is to explore the effects of arbuscular mycorrhizal(AM)fungi inoculation on the soil physicochemical property in the rhizosphere of A.adsurgens.The experimental design included three levels of water regimes(70%,50%,and 30%of soil relative water content)and three inoculation treatments(uninoculation,control;inoculation with Glomus mosseae;inoculation with indigenous AM fungi of A.adsurgens rhizosphere).With soil water content decreasing,soil easily extractable glomalin(EEG),activities of acid phosphatase,alkaline phosphatase and urease and dry mass of plant significantly reduced,mycorrhizal colonization of indigenous AM fungi significantly increased.Under three water regimes,AM fungi inoculation significantly increased mycorrhizal colonization,soil EEG,total extractable glomalin(TEG),activities of proteinase and urease.Under treatments of 30%and 50% water,AM fungi inoculation significantly improved soil organic matter,available N,activities of acid phosphatase and alkaline phosphatase and dry mass of plant,and reduced soil pH value and available P;soil TEG and alkaline phosphatase in the rhizosphere of A.adsurgens inoculated with indigenous AM fungi were significantly higher than those inoculated with G.mosseae.Under 70% water treatment,inoculation with indigenous AM fungi significantly enhanced dry mass of plant,activities of soil acid phosphatase and alkaline phosphatase.The interaction between soil water content and AM fungi significantly affected mycorrhizal colonization,soil pH,nutrients,EEG,enzymes and dry mass of plant.The results suggested that AM fungi inoculation could promote the growth of A.adsurgens,and ameliorate soil physicochemical property of rhizosphere,the mycorrhizal effects of indigenous AM fungi were superior to those of G.mosseae.