Change in Greenhouse Gas Emissions from Soil in Greenhouse as Affected by Irrigation and Nitrogen Fertilization

Abstract

【Objective】 Facility agriculture has been increasing over the past few decades in China, but greenhouse gas (GHG) emissions from greenhouse agriculture, as well as their response to irrigation and fertilization are obscured. The objective of this paper is to investigate the impact of different combinations of irrigation and nitrogen (N) fertilization on GHG emission from greenhouse tomato production. 【Method】 The experiment was conducted in a solar greenhouse and compared four N applications: 0 kg/hm2 (F0), 150 kg/hm2 (F1), 300 kg/hm2 (F2) and 450 kg/hm2 (F3). For each N application, there were three irrigation amounts with each calculated based on the evaporation measured from an in-house evaporation pan installed in the greenhouse (Epan): 50%(W1), 70% (W2) and 90% (W3) of Epan. 【Result】 The emission of N2O increased after N fertilization. The emissions of CO2 and CH4 did not show noticeable dependence on N fertilization but increased with irrigation amount. The total cumulative emissions of N2O increased significantly with N application, maximizing at 0.959 kg/hm2. The global warming potential of the gasses was positively correlated with N application (P<0.05), and the greenhouse gas emission intensity and tomato yield were both positively correlated with irrigation amount and N application at significant level (P<0.01). 【Conclusion】 Balancing environmental impact and economic benefits, reducing N application coupled with optimizing deficit irrigation can effectively reduce GHG emissions from greenhouse tomato production. For our experiment, the optimal combination was irrigating 90% of water evaporated from an in-house evaporation pan and fertilizing 150 kg/hm2 of nitrogen.

Keywords

• deficit irrigation
• nitrogen application
• global warming potential
• greenhouse gas intensity