Vertical distribution and seasonal variation of soil moisture after drip-irrigation affects greenhouse gas emissions and maize production during the growth season

Abstract

Providing enough food for the increasing global population is difficult due to water shortages, which can be partially resolved by regulating soil moisture. Soil moisture influences soluble nutrient uptake and microbial activity, which determine crop growth, but also affects greenhouse gas (GHG) emissions. Farming is increasingly contributing to GHG emission, but little is known about the effects of the vertical soil moisture distribution on GHG or maize (Zea mays L.) yield over the growth season. In this study, there were five irrigation treatments: no irrigation (NI), and irrigation of the top (0–30 cm) (TI), middle (30–60 cm) (MI), bottom (60–90 cm) (BI), and all (0–90 cm) (AI) soil layers. The results showed that TI, MI, BI, and AI increased CO2 (25–60%), CH4 (80–270%), and N2O (17–96%) emissions, and the global warming potential (25–63%), while also increasing grain yield (13–119%) and reducing GHG intensity by 12–27%. While higher soil moisture in the shallow soil layer increased grain yield and GHG emissions, GHG intensity was lowest. Subsurface irrigation or control of the “drip irrigation interval” improve grain yield and resource use efficiency with lower environmental costs contributing agricultural sustainable development.