The Effect Of Cultivated Forage On Soil Respiration Rate And Soil Microbial Respiration Quotient

Grassland degradation and desertification was more and more severity in Inner Mongolia. And then, establishing manual grassland was one of the approaches to restore vegetation, prevent grassland degradation, increase production benefit and exert grassland ecological function. In this study, the cultivated forage that established on degraded grassland and sandy land was selected to analyze the effect of cultivated forage on soil, by measuring soil CO₂ flux in situ and soil microbial eco-physiological indexes such as soil microbial biomass, respiration quotient, expecting to provide theoretic proof to reasonable use and technological management of cultivated forage.The main results are as follows:1. In situ soil respiration rate was mainly controlled by two factor, temperature and water. When soil water content was abundant, there was exponent positive relation between soil respiration rate and soil temperature; at low soil water content, following temperature turn high, soil respiration rate would decrease.2. The in situ soil respiration of cultivated forage that established on agropastoral degraded grassland had seasonal dynamic, higher in autumn then in summer.3. Using organic fertilizer would increase soil respiration. The more fertilizer used, the higher in situ soil respiration was.4. Compare with Pascopyrum smithii, Medicago sativa + Bromus inermis, Lespedeza davurica, Lespedeza hedysaroides, Ceratoides arborescens and Hedysarum fruticosum, Agropyron cristatum and Bromus inermis would more evidently improve the soil microbial eco-physiological index.5. After cancelled farming to establish cultivated forage, the soil microbial index was improved. After sowing mix-genus herbages, the microbial index in salt-wild soil improved greatly.6. The measure that transformed Artemisia intramongolica community to establish cultivated forage was useless to improve sandy soil condition, the measure decreased soil microbial index.