Responses of Soil Nematode Communities to Different Fertilizer Measures in a Peach Orchard

Soil nematodes constitute a vital component of the soil food web, playing a crucial role in ecosystem energy flow and material cycling. They serve as important bioindicators for assessing soil health and ecosystem recovery. However, research exploring the effects of selenium and organic fertilizers on soil nematode community and structure remains limited. In this study, we selected locally used bio-organic fertilizer as a control (CK) and established various fertilization strategies in a newly established peach orchard in southwestern China. These strategies included rapeseed meal cake fertilizer (RMC), green manure (Euphorbia helioscopia, GM), selenium fertilizer (SF), a combination of green manure + rapeseed meal cake fertilizer (GM + RMC), and a combination of selenium fertilizer + rapeseed meal cake fertilizer (SF + RMC). High-throughput sequencing and q-PCR methods were employed to determine the nematode genus composition and abundances. The results revealed GM + RMC significantly increased the total abundance of soil nematodes, while SF enhanced nematode diversity. Furthermore, GM + RMC notably promoted the metabolic activity of bacterivorous nematodes, and SF boosted the metabolic activity of fungivorous nematodes. However, most ecological indices of soil nematode communities did not exhibit significant differences among the six fertilization treatments. This may be attributed to the relatively short duration of the fertilization treatments. The soil nutrient level, particularly total nitrogen, emerged as the primary factor shaping the soil nematode community and its functional groups. Our findings provide a deeper understanding of how nematode communities respond to fertilization measures in orchard ecosystems and offer valuable insights into sustainable development management.