Response of soil nematode communities in Stipa baicalensis meadow steppe to mowing frequencies

Soil nematodes are essential indicator of organisms for assessing the health of grassland ecosystems, and their community structure is sensitive to changes in grassland utilization practices. However, there is still a lack of research on how long different mowing frequencies affect the characteristics of soil nematode communities. Therefore, this study aimed to address this gap by studying the impacts of different mowing frequencies M1, M2, and M3 on the nematode community structure and metabolic footprints. The results showed that a total of 45,320 soil nematodes were captured in the experimental area. Among them, the most dominant genera were Cervidellus and Acrobeloides (23.84%), and the dominant genera were Nygolaimus, Chiloplacus and Cephalobus (20.57%). Compared with no mowing treatment, the total abundance of soil nematodes and the abundance of each trophic group showed inflection points in the M2 treatment. The life history of nematode community tended to be k-strategist, and the Wasilewska index was > 1, indicating that soil microbivores were sensitive to the environment and the soil mineralization pathway did not change. NCR value was > 0.5, indicating that the decomposition of grassland organic matter is still dominated by bacterial and fungal channels, which is not affected by mowing frequency. In addition, Soil pH and ammonium nitrogen (NH₄⁺-N) are environmental factors that affect nematode communities. In summary, M2 treatment can increase nematode diversity and metabolic activity, improve anti-interference and soil health, and promote soil food web maturation. It is the best cutting frequency for grassland soil health, and has potential benefits for grassland restoration.