Effect of alternate partial root-zone drip irrigation on soil bacterial communities and tomato yield

- ADI changed root-zone soil bacterial community significantly.
- Root length and activity affected soil bacterial communities deeply.
- 70% FC improved nitrogen and sulfur metabolism in root-zone soil.
- Soil bacterial community changing in ADI improved tomato yields.

The aim of this study was to assess the effect of alternate partial root-zone drip irrigation (ADI) on the soil microbial communities in the crop root zone and the relation between the soil microbial community changes and crop growth. We investigated the effect of ADI at different lower limits of irrigation (ILLs, 50%, 60%, and 70% of the field capacity (FC)) on soil bacterial diversity in the root zone of greenhouse tomato and analyzed the relation between the soil bacterial community changes and tomato growth. The soil bacterial community structure was markedly different under ADI compared with SDI (ground drip irrigation). It was closely related to the soil microenvironment. Among various environmental factors, the tomato root activity, root length, and soil CO2 flux showed significant effects on the difference in soil bacterial communities. Environmental changes in the root-zone soil inevitably affected crop growth, and SDI and ADI resulted in significant differences in root growth, single fruit weight, number of fruits and fruit yield per tomato plant. Our results suggest that an ILL at 70% of the FC could significantly improve the root-zone soil environment, which was beneficial for the organic matter, cellulose, nitrogen and sulfur metabolism and increased the oxygen content in the root-zone soil. Therefore, the root areas, root forks, the fruit number and the yield per plant were better under an ILL at 70% of the FC.