A Comparative Study On The Differences Of Soil Properties Between Rhizosphere And Non-Rhizosphere Of Typical Plant In The Loess Hilly Region

The degradation of soil quality by vegetation deterioration in the loess hilly region has threatened the ecological environment and agriculture sustainable development. Therefore, improving soil quality and speeding up the process of vegetation restoration is one of important goals in ecological rehabilitation project of loess hilly region. 16 typical species of plants were chosen from two representative regions (grassland zone and forest zone) in the loess hilly region, to study the difference of soil chemical properties and soil microbial functional diversity between the rhizosphere and non-rhizosphere by using field sampling and laboratory analysis. The resaech results will provide scientific evidence for preserving or improving soil quality, increasing soil fertility, and use efficiency of nutrient resources, protecting ecological environment. The main research results were as follows:(1) Soil chemical properties (organic C, total N, ammonium N, nitrate N, total P, availabel P, available K), soil enzyme activity (invertase, urease, alkaline phoshpatase, dehydrogenase), soil microbial biomass (Cmic, Nmic, and Pmic), basal respiration and soil microbial functional diversity (AWCD, soil microbial diversity index and uniformity index) are different whether rhizosphere soil or non-rhizosphere soil among 16 species of plant in grassland zone and forest zone in the loess hilly region. In grassland area, all kinds enzymes and Cmic,Nmic,basal respiration in the rhizosphere soil of Artemisia frigida was higher than other plants, alkaline phoshpatase activity was 84.53 mgP2O5.kg^-1.h^-1, dehydrogenase activity was 24.97 ulH+.g^-1.h^-1, they were significant higher than other plants; the main trend of chemical properties,soil enzyme activity,soil microbial biomass in the rhizosphere and non-rhizosphere soil of Lespedeza bicolor Turcz was lower; content of organic C were 8.14 and 5.53 g.kg^-1 respectivety in the rhizosphere soil and non-rhizosphere soil, they were significant lower than other plants; In forest area, major indicators in the rhizosphere soil of Bothriochloa ischcemum was higher than others plants. content of organic C was 20.59 g.kg^-1, content of total N was 2.71 g.kg^-1, content of Cmic was 547.61 mg.kg^-1, dehydrogenase activity was 32.27 ulH+.g^-1.h^-1, they were significant higher than other plants; the rhizosphere soil microbial activity(AWCD), soil microbial diversity index and uniformity index of A. sacrorum, A. frigida, and Quercus liaotungensis Koidz were high, shown that rhizosphere soil microbial metabolic intensity in these three plants are fiercer than others.(2) Soil chemical properties, soil enzyme activity, soil microbial biomass and soil microbial functional diversity in rhizosphere soil were higher than in non-rhizosphere soil for most of plants,and the difference of total P in all kinds plant is not significant between rhizosphere soil and non-rhizosphere soil. In grassland area, for Asarum sieboldii Miq, the content or activity of availabel P, urease, alkaline phoshpatase, dehydrogenase , Cmic, and Pmic in the rhizosphere soil was lower than in the non-rhizosphere soil, but the remaining indicators in the rhizosphere soil was higher than in the non-rhizosphere soil; In forest area, there was no significant law among indicators of Robinia Pseudoacacia between rhizosphere soil and non-rhizosphere soil, alkaline phoshpatase of Robinia Pseudoacacia in rhizosphere soil was lower than in non-rhizosphere soil 38.43 mgP2O5.kg^-1.h^-1, there was apparent difference. For Bothriochloa ischcemum, there were apparent difference between rhizosphere soil and non-rhizosphere soil for most indicators.(3) In grassland area, the major carbon sources of all species of plants'rhizosphere soil microbe were carboxylic acid sort and amino acids sort, and in non-rhizosphere soil were carboxylic acid sort, amine sort, and amino acids sort. In forest area, the major carbon sources of all species of plants'rhizosphere soil microbe were carboxylic acid sort and amino acids sort, and in non-rhizosphere soil were carbohydrate and carboxylic acid sort.(4) There were significant correlations between organic C, total N, invertase, Cmic, and Nmic in rhizosphere and non-rhizosphere soil under different plants. There were significant correlation between different species of plants'Soil microbial activity (AWCD), soil microbial diversity index, and uniformity index, but the correlation of soil microbial activity (AWCD), soil microbial diversity index, and uniformity index to other indicators were not obvious. The rest of indicators's correlation is different.(5) By principal components analysis, in all indicators among 9 species of plants in typical grassland area, organic C, total N, invertase, alkaline phoshpatase, Cmic, Nmic, basal respiration, soil microbial diversity index, and uniformity index can be used as the indices to evaluate soil quality. Unlike grassland zone, organic C, total N, nitrate N, total P, availabel P, available K, invertase, urease, Alkaline phoshpatase, Cmic, AWCD, soil microbial diversity index, and uniformity index can general reflect soil chemical and microbial properties under 7 species of typical plants in forest zone.