[Effects of optimized fertilization on nematode community in greenhouse soils]

Excessive fertilization easily leads to the degradation of greenhouse vegetable fields, therefore rational fertilizations are important to maintain the production and sustainable development of vegetable. In this study, two fertilization treatments (optimized fertilization and conventional fertilization, noted as OF and CF, respectively) under continuous tomato-pepper cropping were arranged to investigate soil physicochemical properties, abundance and trophic groups of nematode and vegetable yield. The results showed that OF could maintain soil pH at the relatively higher level and increase the yield of tomato and pepper by 9.0% and 6.9% compared to CF treatment. In contrast to CF, OF increased nematode quantity and the relative abundance of bacterivores, but decreased the relative abundance of fungivores and plant-parasites, more obviously in the growth season of tomato. No obvious differences in plant parasite index, diversity, and richness were observed between CF and OF treatments across all sampling stages of tomato and pepper. Nematode channel ratio ranged from 0.39 to 0.64 in CF treatment, which was significantly lower than that in OF treatment (0.67-0.84), suggesting that the decomposition of food network was dominated by fungi in CF treatment but by bacteria in OF treatment. Based on soil physicochemical properties, nematode groups and vegetable yield, we concluded that optimized fertilization could not only increase vegetable growth but also improve soil ecological environment.