Contributions of Ammonia-Oxidizing Archaea and Bacteria to Nitrous Oxide Production in Intensive Greenhouse Vegetable Fields

Abstract

With excessive nitrogen (N) input, high nitrous oxide (N2O) emissions are frequently observed in greenhouse vegetable fields. We hypothesized that the underlying production mechanisms can be derived across a wide selection of vegetable fields in the middle and lower reaches of the Yangtze River. Thus, we investigated the emission characteristics and relative contributions of ammonia-oxidizing archaea (AOA) and bacteria (AOB) and other microbial processes to the N2O production from five long-term greenhouse vegetable fields through an incubation experiment with combined inhibition methods. The results showed that the ammonia oxidation process is the dominant contributor to N2O production at all five sites, accounting for 88–97% of the total N2O emissions. Regardless of acidic, neutral, or alkaline soil, AOA-driven N2O emission rates were consistently higher than AOB-driven N2O emission rates. Both AOA-driven and AOB-driven N2O emissions exhibited positive correlations with soil pH, with significant increases in soil N2O production associated with high pH levels. Therefore, general production mechanisms were derived, such that more attention should be paid to AOA-driven N2O emissions and to vegetable soils with a relatively high pH in the middle and lower reaches of the Yangtze River.

Effective Control of the Nitrogen Gap—Higher Yields and Reduced Environmental Risk

“…According to Zhong et al [30], in soils where vegetables are grown and fertilized with large doses of nitrogen, AOB plays a greater role in ammonia oxidation than AOA. Dong et al [31] confronted the conclusion of Zhong et al [30], assessing the role of both groups of microorganisms in N 2 O emissions in five selected subregions of the middle and lower reaches of the Yangtze River. The authors documented that the ammonia oxidation process is responsible for N 2 O production in greenhouse vegetable fields, accounting for 88-97% of the total N 2 O emissions.…”