International Journal of Environmental Science and Development

Abstract—Soil fertilization is one of the major sources for nitrous oxide (N₂O) emissions and soil moisture is among the most important factors affecting its production. Thus, one of the important mitigation strategies in semiarid or arid regions is through irrigation and/or fertigation management. The objective of this research was to evaluate the effects of different drip irrigation methods and N application levels on N₂O emissions. Nitrous oxide emission flux and N₂O concentration in soil profile were measured in a pomegranate field for two growing seasons under two irrigation systems [subsurface drip irrigation (SDI) at ~0.5 m depth and traditional surface drip irrigation (DI)], and three N application rates (50%, 100%, and 150% of current practice rate). Both years’ data showed that N₂O emissions has a high and positive correlation with N fertilization events and application levels. Nitrous oxide emissions from DI at 100% and 150% N levels were over an order of magnitude higher compared to those from SDI based on the data of the first year. Data from the second year confirmed the first year’s findings of high emissions from DI. A positive linear correlation between the N₂O emission flux and N₂O concentration in soil-gas phase was identified that supported emission data. This research demonstrated that although N fertilization is a major cause for N₂O emissions, subsurface drip irrigation/fertigation can lead to a significant emission reduction in addition to other benefits, such as increased water and nutrient use efficiencies, and reduced weed pressure.

Index Terms—Chemical nitrogen fertilizer, greenhouse gas emission, high-frequency drip irrigation.

S. Gao, and A. Hendratna are with USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Parlier, CA, USA 93648 (e-mail: suduan.gao@ars.usda.gov, aileen.hendratna@ars.usda.gov).
Z. Cai and Y. Duan is with Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China (e-mail: caizejiang@caas.cn, duanyinghua@caas.cn).
R. Qin is with Hermiston Agricultural Research & Extension Center, Oregon State University, Hermiston (e-mail ruijun.qin@oregonstate.edu).
R. Tirado-Corbalá is with Agro-Environmental Science Department, University of Puerto Rico, Mayagüez, Puerto Rico, USA (e-mail: rebecca.tirado@upr.edu).

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Cite: Suduan Gao, Aileen Hendratna, Zejiang Cai, Yinghua Duan, Ruijun Qin, and Rebecca Tirado-Corbalá, "Subsurface Drip Irrigation Reduced Nitrous Oxide Emissions in a Pomegranate Orchard," International Journal of Environmental Science and Development vol. 10, no. 3, pp. 79-85, 2019.