Soil N2O and N2 emissions during anaerobic soil disinfestation period in a greenhouse vegetable production system: quantified by in situ 15N labeling method

Abstract

Abstract Background and Aims: Greenhouse vegetable production (GVP) is expanding worldwide. The high application of nitrogen (N) fertilizers has caused soil diseases and nitrate residue. Farmers usually adopt anaerobic soil disinfestation (ASD), involving organic carbon addition, extensive irrigation, plastic films laying, and greenhouse sealing during the summer fallow. These conditions may promote denitrification, causing nitrous oxide (N2O) and dinitrogen (N2) emissions. However, this is rarely reported. Methods: We used ¹⁵N labeling for in situ monitoring of N₂O and N₂ emissions during ASD in a GVP system in Shouguang, Northern China. Two treatments were implemented: conventional organic fertilization (Fertilizer) and a control (No-fertilizer), with continuous monitoring over 14 days. Results: Within 14 days, cumulative gaseous N emissions in Fertilizer and No-fertilizer treatments were 0.82, 0.47 kg N ha-1 for N2O, and 40.7 and 25.5 kg N ha-1 for N2, respectively. Organic fertilization significantly increased N2O and N2 emission. From days 1–6, the predominant gaseous N was N2, with an N2O/ (N2O + N2) ratio (RN2O) between 0.007 and 0.015. From days 7–14, N2O proportion increased, with RN2O ranging from 0.21 to 0.75. Isotopic information showed that denitrification contributed to 48.9%–51.2% and 27.1%–36.7% of total N2O and N2 emissions. The structural equation model showed that high soil temperature during ASD significantly reduced N2O emissions. Conclusion: Our findings emphasize the importance of N2 emissions in N loss and provide a basis for studying the fate of N, as well as developing measures to reduce N2O emissions within GVP systems.