Study On Soil Phosphorus Availability Under Different Vegetation Restoration In Degraded Hilly Red Soil Region

Phosphorus is an essential nutrient element for plant growth and development,and is a key limiting factor for plant growth in red soil region of subtropical hilly region.However,the effect of vegetation restoration on soil PHOSPHORUS availability in degraded red soil region is not clear.Therefore,in this study,two kinds of artificial forests(Schima superba pure forest and Pinus Massoniana pure forest)and naturally restored shrub and grass land(control)were reconstructed for 28 years in the red soil area of typical degraded hills.The seasonal changes of soil phosphorus content,soil enzyme activity,soil microbial quantity and phosphorus solubating fungi community composition and rhizosphere effect under different vegetation restoration in red soil region of subtropical hill were studied by analyzing the various forms of phosphorus content and soil biological properties of rhizosphere soil and non-rhizosphere soil in different seasons.The physical,chemical and biological factors affecting soil phosphorus availability of artificial forest in degraded red soil region of subtropical region were analyzed.To evaluate the advantages and disadvantages of artificial forest types in the degraded red soil region of subtropical hills,and provide scientific basis for ecological restoration in the degraded red soil region of subtropical hills.The results show that:(1)The contents of organophosphorus,Al-P,Fe-P and acid phosphatase in the rhizosphere of schima superba pure forest and Masson pine pure forest were significantly higher in spring,summer,autumn and winter than those in the naturally restored shrub and grassland.The mean values of soil organic phosphorus content,Al-P content,Fe-P content and soil acid phosphatase activity in rhizosphere of Schima superba pure forest and Masson pine pure forest were increased by 0.11 g·kg-1 and 0.07 g·kg-1,respectively.32.13mg·kg-1 and 23.18 mg·kg-1,0.67 mg·g-1·d-1 and 0.58 mg·g-1·d-1.The non-rhizosphere soil microbial biomass p of masson pine pure forest was significantly higher than that of shrub-grassland in spring,summer,autumn and winter,and the mean value increased by29.95 mg·kg-1.The acid phosphatase activity of SCHima superba pure forest and Masson Pine pure forest was significantly higher than that of shrub-grassland in spring,summer,autumn and winter.The mean values of the four seasons increased by 0.83 mg·g-1·d-1 and0.70 mg·g-1·d-1,respectively.(2)There was no seasonal change in soil microbial biomass p content in the rhizosphere of SCHba superba pure forest,Masson pine pure forest and natural restoration shrub-grass,and the non-rhizosphere showed winter > spring > summer > autumn.The content of organophosphorus in rhizosphere showed no seasonal change,and the non-rhizosphere showed a trend of winter > spring > summer > autumn.There was no seasonal change in available p content in rhizosphere soil,and the non-rhizosphere soil showed winter < spring,summer and autumn.(3)The contents of organophosphorus,microbial biomass P and available P in the rhizosphere soil of superba superba and Masson pine pure forests were significantly higher than those in non-rhizosphere soil.(4)Soil p H value and acid phosphatase activity are the key factors affecting soil phosphorus availability.(5)Vegetation restoration can improve soil microbial diversity.Mortierellomycota,Ascomycota and Basidiomycota are the key phosphate-soluting fungi affecting available phosphorus.In conclusion,plantation significantly improved soil phosphorus availability and biodiversity,and promoted ecological restoration.