Carbon Dioxide Flux Affected By Drip Irrigation Method in a Pomegranate Orchard.

Mitigation of greenhouse gas emissions has become essential to improve the sustainability of agricultural production systems. California faces a number of challenges with the efficient water and nutrient use as top issues in sustainable agriculture. In this research, field monitoring was carried out to evaluate the effects of drip irrigation methods on CO₂ flux in a pomegranate field with subsurface drip irrigation (SDI) and surface drip irrigation (DI) systems.  For each irrigation system, three N application rates (50%, 100%, and 150% plant requirement) were applied.  Data show that CO₂ flux not only is affected by the irrigation method, but also varied significantly spatially and temporally. Daily peak CO₂ flux appears much higher from DI system than from SDI system. Increasing N application rates also showed a positive correlation with CO₂ flux.  The highly spatial variation in CO₂ flux, caused by water and tree root distribution should  be considered when estimating total CO₂ emissions in orchard settings.