Fertilizer effects on soil microbial communities and organic matter in the rhizosphere ofsitanion hystrixandagropyron smithii

Abstract

Abstract The effects of fertilizer on soil microbial communities and organic matter in the rhizosphere of an early successional grass, bottlebrush squirreltail (Sitanion hystrix), and a later successional grass, western wheatgrass (Agropyron smithii), were evaluated in afield experiment. Fertilization resulted in significant decreases in fungal hyphal lengths in the rhizospheres of both grasses and decreases in the microbial biomass, soluble organic carbon, and soil organic matter carbon in the rhizosphere of Sitanion. For Agropyron, the bacterial numbers, microbial biomass, soluble organic carbon and soil organic matter did not show these responses to fertilization. In addition, utilization of amino acids and other nitrogen‐containing nutrients by bacterial isolates from the early successional Sitanion significantly decreased with fertilization, which did not occur with the bacterial isolates from Agropyron. These results suggest that fertilization will have more distinct effects on rhizosphere microorga...