LANZHOU — Chinese scientists have recently revealed how long-term cultivation impacts soil fauna diversity and the stability of ecological networks in desert agricultural ecosystems, according to the Northwest Institute of Eco-Environment and Resources of the Chinese Academy of Sciences.

The study provides a scientific foundation for evaluating soil health in oasis farmlands, with the findings published in two journals, Agriculture, Ecosystems and Environment, and Plant and Soil, according to the NIEER.

Soil fauna is a core component of soil food webs. However, its diversity is declining due to climate change and human activities, which is further driving the evolution in the structure and function of soil food webs, according to Liu Jiliang, an associate researcher at the NIEER.

Liu said that the decline rate in soil fauna diversity and function in global agricultural ecosystems exceeds that of other ecosystems. Intensive cultivation has caused multi-trophic-level declines in soil fauna diversity and triggered cascading effects, weakening the multiple functions of soil food webs in biological control of pests and diseases, litter decomposition, nutrient cycling and degradation of harmful substances. This, in turn, undermines soil health and stability.

The NIEER research team conducted an in-situ study at the field scientific observation and research station for farmland ecosystems, which is based in the oasis in Zhangye, Northwest China's Gansu province.

The study aimed to uncover the coupled effects and feedback mechanisms of oasis farmland cultivation and abandonment-driven interactions between vegetation and soil environment on soil fauna diversity and function.

The study sites included both abandoned land and cultivated farmland with farming histories of 10, 30, 50 and 100 years. Using natural desert as the control group, scientists systematically analyzed changes in soil fauna diversity and functional traits using the space-for-time substitution method.

The study found that compared with natural desert, cultivated farmlands in arid regions significantly boosted soil fauna diversity, while trophic functions increased alongside cultivation duration. However, long-term cultivation and abandonment both negatively impacted soil fauna diversity and function, subsequently affecting soil health and stability.

The findings indicated that cultivation in oasis farmlands can help improve the soil environment, increase the abundance and diversity of herbivorous and other feeding soil fauna, and reshape the trophic structure and function of soil fauna communities.

Therefore, a comprehensive analysis of the long-term response patterns of soil fauna diversity to oasis farmland cultivation can help unveil their intrinsic link with soil functions. It can also help assess the indicative role of soil fauna food web in ecosystem stability and can provide a scientific basis for soil health evaluation in oasis farmlands, according to Liu.

Xinhua