How Grazing affects Soil Microbial Communities

By: Eliza Elizondo

The influence of grazing on soil microbial communities. The arrows represent the relationship between grazing, microbial communities, and land degradation. The plus signs represent the positive effects and the minus sings represent the negative effects in each relationship. Photo taken from Yang et al, 2018. 

Grazing is a practice used to promote plant diversity and preserve the ecosystem. Moreover, grazing can affect the soil microbial community by animal trampling and manure deposition. In a study conducted by Fei Yang and colleagues, at the Alpine Meadow and Wetland Ecosystem Research Station of Lanzhou University in China, three grazing systems were used. They were no grazing, winter grazing, and annual grazing. No grazing took place in a small area of 0.35 ha and no activity was done. Winter grazing took place in an area of 12 hectare with 12 yaks per hectare and was only grazed from October to April. Annual grazing took place in an area of 16 hectare with 18 yaks per hectare and was done in time intervals in order to allow plant regrowth. This study was performed in a period of five years and then soil samples were taken from 5 cm above the surface and up to 30 cm below the surface. Winter grazing was discovered to affect microbial communities by resource availability such as a decrease in total soil carbon and nitrogen. There was also an increase of fungi and a decrease of bacteria, an instability caused by the deposits of urine and manure. It was then determined that annual grazing was a more beneficial grazing system for microbial communities as it did not interfere with resource availability or microbe stabilization. 

Original Article:
Yang, F., Niu, K., Collins, C. G., Yan, X., Ji, Y., Ling, N.,... Hu, S. (2018). Grazing practices affect the soil microbial community composition in a Tibetan alpine meadow. Land Degradation & Development, 30(1), 49-59.