Interactive effects of short-term nitrogen enrichment and simulated grazing on ecosystem respiration in an alpine meadow on the Tibetan Plateau Effects of straw and plastic-film mulching on soil micro-bioactivity and organic carbon and nitrogen in northwest dryland areas of China Effects of Astragalus sinicus manure and fertilizer combined application on biological properties of soil in Anhui double cropping rice areas along the Yangtze River Effects of temperature and moisture on soil nitrogen mineralization of lucerne stands Effect of Plant Growth-Promoting Rhizobacteria (PGPR) on the Microorganism Population and Bacterial Diversity in Ziziphus jujuba Rhizosphere Soil Effects of nitrogen application on carbon metabolism of soil microbial communities in eucalyptus plantations with different levels of soil organic carbon