Drip fertigation with straw incorporation promotes soil microbial network complexity and potentially reduces pathogen abundance in greenhouse vegetable production systems

Continuous monoculture, conventional flood fertigation and low soil fertility increase the risk of soil-borne diseases in greenhouse vegetable production systems. Drip fertigation with straw incorporation (DIF+S) significantly improves resource use efficiency and reduces environmental risks compared to conventional fertigation. However, it remains unclear whether DIF+S positively affects soil microbial diversity and community structure and reduces the occurrence of soil-borne diseases. Therefore, a two-factor field trial was conducted in a greenhouse tomato production system with drip vs. flood fertigation, with and without straw incorporation across the seven growing seasons. The experimental treatments were as follows: (i) conventional flood irrigation with overfertilization (CIF); (ii) CIF + straw incorporation; (iii) drip fertigation with reduced irrigation and fertilization (DIF); and (iv) DIF + straw incorporation. Across the seven growing seasons, the average water and nitrogen use efficiency (WUE and NUE) was two- and threefold higher for DIF than for CIF, respectively, whereas tomato yields remained high. DIF significantly increased soil bacterial diversity and network complexity compared to CIF but had no effect on the soil fungal community. DIF significantly reduced the relative abundance of Fusarium-induced tomato wilt. Moreover, straw application significantly decreased fungal diversity while increasing fungal network complexity, although no effect on the bacterial community was found. The relative abundance of plant pathogens, such as Cladosporium, Fusarium and Alternaria, which are related to soil-borne diseases of tomato plants, was significantly reduced when straw was incorporated. Our results highlight that drip fertigation combined with straw incorporation significantly positively affects soil microbial diversity and stability. Thus, DIF+S is a sustainable and effective technology for maintaining soil health and reducing pesticide use in greenhouse vegetable production systems.