Drip irrigation mode affects tomato yield by regulating root–soil–microbe interactions

Abstract A deep understanding of root–soil–microbe interactions in response to drip irrigation can help optimize drip irrigation techniques and improve crop yield; however, relevant knowledge remains limited. In this study, field experiments were conducted for two consecutive years to investigate the effects of surface drip irrigation (DI), subsurface drip irrigation (SDI), and alternate drip irrigation (ADI) on root–soil–microbe interactions and tomato yield. The results showed that the soil moisture distribution uniformity in the root zone (0–60 cm depth) was reduced in the order SDI > DI > ADI. In the SDI treatment, the tomato root lengths were 4.83- and 3.94-fold higher than those in the DI and ADI treatments, respectively, and the relative abundances of Patescibacteria in the bacterial community and Blastocladiomycota in the fungal community were significantly elevated. In the ADI treatment, the root length was 1.23-fold higher than that in the DI treatment, and the relative abundance of Patescibacteria also increased significantly compared with that in the DI treatment. These changes led to distinct root–soil–microbe interactions. The most intensive positive root–soil–microbe interactions occurred in the SDI treatment, followed by the ADI and DI treatments. The differences in the root–soil–microbe interactions regulated tomato yield. The tomato yield in the SDI treatment was increased by 19.77% and 7.77% compared with that in the DI and ADI treatments, respectively. In the ADI treatment, the tomato yield was 24.09% higher than that in the DI treatment. Therefore, the different drip irrigation methods can regulate tomato yield by affecting root–soil–microbe interactions. The results provide a reference for the optimization of the drip irrigation mode to regulate root–soil–microbe interactions and increase tomato yield.