Biodiv Sci ›› 2022, Vol. 30 ›› Issue (12): 22575.

• Original Papers •

### Effects of soil macro- and meso-fauna on the decomposition of cattle and horse dung pats in a semi-arid steppe

Jianwei Cheng1,2, Yadong Wang2, Yanan Wang2, Ying Li2, Ying Guo2, Zheng Bai2, Xinmin Liu3, Frank Yonghong Li2,*()

1. 1. School of Geography Science, Taiyuan Normal University, Jinzhong, Shanxi 030619
2. Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021
3. School of Life Science and Technology, Inner Mongolia Normal University, Hohhot 010022
• Received:2022-10-10 Accepted:2022-11-28 Online:2022-12-20 Published:2022-12-08
• Contact: *E-mail: lifyhong@126.com

Abstract:

Aims: Soil fauna as the key component of terrestrial ecosystems, playing an important role in decomposition of animal dung, mineralization of organic matter and turnover of soil nutrients. Many studies have been done on the soil fauna’s effects on plant litter’s decomposition. Still, less information is available on their impact on the decomposition of animal dung.
Methods: Here we conducted a field experiment in a temperate semi-arid steppe ecosystem to investigate the effect of the different soil fauna groups with different body sizes on the decomposition of horse and cattle dung pats on the soil surface over a one-year period. The experiment had five treatments: CK, soil only, no dung nor soil fauna; T0, dung pat covered with a wire-mesh-cage of 0.425 mm holes (excluding dung beetles and soil meso-fauna); T1, dung pat covered with a wire-mesh-cage of 1 mm holes (excluding dung beetles); T2, dung pat covered with a wire-mesh-cage of 2 mm holes (excluding tunneler dung beetle); T3, exposed dung (with no exclusion of soil fauna).
Results: We found that (1) compared with dung only (excluding dung beetles and soil meso-fauna) treatment (T0), the presence of soil fauna (T1, T2 and T3) did not enhance the dry mass loss of livestock dung during the first 60 days of the experiment; in contrast, in the presence of all soil fauna (T3) significantly increased the dry mass loss of cattle dung but decreased that of horse dung at the end of the experiment (at day 360). (2) Soil fauna also enhanced the decline rate of carbon and nitrogen content in dung during the first 60 days of the experiment. (3) Dung addition increased the soil microbial respiration, and the increase was most obvious in the presence of soil fauna (T3) on days 15 and 30 of the experiment. (4) Compared to the soil with no dung (CK), the soil with horse dung had higher contents of soil available N, soil organic carbon and soil moisture, and the contents were higher in the presence of soil fauna (T2 and T3); whereas the soil with cattle dung had no changes.
Conclusion: We conclude that the feeding and activities of dung beetle in the early stage of dung decomposition alter the physicochemical properties of dung, which indirectly affect the role of soil biota in the decomposition in the later stage.