Degradation dynamics and microbial processes in yak dung on the Tibetan Plateau

作者：Zhiyang Zhang, Yi Jiao, Steffen Kolb · 发表于：Soil Biology and Biochemistry · 年份：2024 · DOI：10.1016/j.soilbio.2024.109675 · 被引用次数：18 · 研究领域：Rangeland Management and Livestock Ecology、Soil Carbon and Nitrogen Dynamics、Soil erosion and sediment transport

Yak dung is an input to the carbon (C) and nutrient cycles that maintain ecosystem functions on the Tibetan Plateau. Yak dung is C and nutrient-rich excreta that is conducive to the growth and metabolic activities of bacterial communities, thus predicting that more bacterial than fungal processes are responsible for the degradation of yak dung. A three-year yak dung degradation experiment in a yak-grazing alpine rangeland was designed to investigate the changes in dung moisture content, chemical and enzymatic properties, and bacterial and fungal communities during degradation, as well as to explore how these parameters may regulate the degradation of yak dung. After three years of decomposition, yak dung had a 79 % reduction in mass, and most of the mass loss occurred within the first 2 years. Cellulosic polymers, especially cellulose and hemicellulose, determined the rate of yak dung degradation. The main changes in dung bacterial communities occurred during the first 2 years of degradation, largely related to changes in moisture and available substrates (e.g., dissolved organic C, dissolved organic nitrogen (N), ammonium, nitrate, and available phosphorus). In contrast, dung fungal communities did not change until 1.5–3 years of degradation, in response to the total substrates (e.g., total C and N). The relative abundances of Proteobacteria , Bacteroidota , Firmicutes , Basidiomycota , and Ascomycota , and the activities of endo-cellulases, exo-cellulases, β-1,4-glucosidase...