水保所知识产出(1956---)知识库

The lack of knowledge on the effects of alternating drip irrigation (ADI) on soil gas emissions limits the un-
derstanding of the trade-off between irrigation and soil gas emissions. To determine the effects of ADI on soil gas
emissions, this study investigated soil gas emissions, microbial community composition and root–soil in-
teractions in a tomato crop under ADI with different lower limits (50%, 60% and 70% field capacity (FC)), with
mulched drip irrigation (MDI) used as a control. ADI with different lower limits differentially affected root
growth and microbial community composition. These differences regulated root–soil interactions and affected
soil gas emissions. Compared with ADI at 60% FC, ADI at 50% and 70% FC increased root fork numbers by 14.7%
and 26.5%, respectively, and compared with MDI and ADI at 60% FC, these treatments also increased the
abundance-based coverage estimators of bacterial communities. Furthermore, the total cumulative CO 2 emis-
sions from ADI at 50% and 70% FC were 42.1% and 46.8% greater than that of MDI, respectively, and the total
cumulative N 2 O emissions from both treatments were 70.0% and 35.0% greater than those under MDI,
respectively. Compared with MDI, ADI at 60% FC increased the total cumulative CO 2 flux by 27.7%, although the
latter decreased the root fork numbers and abundance-based coverage estimators of bacterial communities.
Importantly, the tomato yield and water-use efficiency under ADI at 60% FC were intermediate for the various
treatments, and the yield-scaled soil gas emissions were significantly lower than those under ADI at 50% and
70% FC. Therefore, ADI at 60% FC is a suitable irrigation method for optimizing tomato crop water-use efficiency
and reducing gas emissions. Taken together, these results provide a new perspective for reducing soil gas
emissions based on regulating the soil microbial community and root–soil interaction mechanisms through soil
water management.