Soil Fungal Community Structure Changes in Response to Different Long-Term Fertilization Treatments in a Greenhouse Tomato Monocropping System

Greenhouse vegetable cultivation (GVC) is an example of intensive agriculture aiming to increase crop yields by extending cultivation seasons and intensifying agricultural input. Compared with cropland, studies on the effects of farming management regimes on soil microorganisms of the GVC system are rare, and our knowledge is limited. In the present study, we assessed the impacts of different long-term fertilization regimes on soil fungal community structure changes in a greenhouse that has been applied in tomato (Solanum lycopersicum L.) cultivation for 11 consecutive years. Results showed that, when taking the non-fertilizer treatment of CK as a benchmark, both treatments of Conventional chemical N (CN) and Organic amendment only (MNS) significantly decreased the fungal richness by 16%–17%, while the Conventional chemical N and straw management (CNS) restored soil biodiversity at the same level. Saprotroph and pathotroph were the major trophic modes, and the abundance of the pathotroph fungi in treatment of CNS was significantly lower than those in CK and CN soils. The CNS treatment has significantly altered the fungal composition of the consecutive cropping soils by reducing the pathogens, e.g., Trichothecium and Lecanicillium, and enriching the plant-beneficial, e.g., Schizothecium. The CNS treatment is of crucial importance for sustainable development of the GVC system.