Ecological Stoichiometry Characteristics Of Plant-Soil Under Different Improvement Modes Of Reclaimed Land In Loess Area Dump

In order to explore a quick and efficient way to improve the soil of mining dump reclamation land in loess region,this study sited Wujiata reclaimed land in Ordos as the research object,and set twelve organic manure-bacterial agent mixing models.Combined with planting leguminous plants,this study determined the growth characteristic of plant,plant stem leaf and root and soil carbon(C),nitrogen(N),and phosphorus(P)content.The C and N contents of soil microbial biomass were analyzed,and the stoichiometric characteristic relationships among plants,soil and soil bacterial biomass were analyzed,and the nutrient restriction and nutrient cycling mechanism in the reclaimed land of dumps were discussed.The main research results were as follows:(1)All of the improvement modes could promote the growth and development of plants.The improvement mode of high dosage of organic manure and high dosage of mixed bacteria had the best promoting effect on plant growth characteristics.Some of the improvement models could improve soil nutrients.The effect of low dosage of organic manure and high dosage of mixed bacterial agent on soil fertility improvement was the best.The total N content of the stem and leaf,organic C and total N contents of root and soil microbial biomass could be increased by all the improvement modes.The improved mode of medium amount of organic manure and low amount of mixed bacterial agent had the best effect on increasing plant nutrient content.(2)The C/N ratio of stem and leaf decreased under all improvement modes.Stem and leaf C/P ratio,N/P ratio were larger except for low dosage of organic manure and high dosage of mixed bacterial agent and medium amount of organic manure modes.The root C/N ratio decreased except in some improved modes,the root C/P ratio increased,and the root N/P ratio increased except in high dosage of organic manure improved modes.Soil C/N ratio increased under the improved mode of high dosage of organic manure and mixed baterial agents.Under the mode of organic manure and low dosage of mixed bacterial agents,C/P ratio increased,while N/P ratio increased under the mode of low dosage of organic manure,low dosage of organic manure and low dosage of mixed baterial agents and high dosage of mixed bacterial agents.Soil bacterial C/N ratio increased except for some improved modes.(3)Plant growth,organic C and total P contents of soil under all improvement modes increased with the increase of organic manure application,while soil total N decreased with the increase of organic manure.Soil total P content decreased with the increase of the application amount of mixed bacterial agents.(4)The stoichiometric characteristics of soil C,N and P in the study area were mainly subject to C and P.The stoichiometric characteristics of soil bacterial biomass C and N in the study area were mainly subject to C.Plant stems,leaves and roots in the study area were still relatively deficient in total P content,and soil nutrients were still relatively deficient.Plant growth were mainly limited to P.This paper contains 20 figures,13 tables and 122 references.