Control of Gas Emissions (N2O and CO2) Associated with Applied Different Rates of Nitrogen and Their Influences on Growth, Productivity, and Physio-Biochemical Attributes of Green Bean Plants Grown under Different Irrigation Methods

The use of nitrogenous fertilizers in agriculture can cause uncontrolled gas emissions, such as N2O and CO2, leading to global warming and serious climate change. In this study, we evaluated the greenhouse gases emissions (GHGs) that are concomitant with applied different rates of N fertilization, such as 60%, 70%, 80%, 90%, 100%, 110%, and 120% of the recommended dose in green beans grown under three irrigation systems (surface, subsurface, and drip irrigation). The obtained results showed that GHGs were positively correlated with increasing the rate of N fertilization. Meanwhile, the subsurface irrigation system followed by drip irrigation achieved the highest significant (p ≤ 0.05) values regarding the growth and pod yield attributes. Furthermore, N supplements at 90% and/or 100% of the recommended dose under the subsurface irrigation system led to the highest concentration of chlorophyll, vitamin C, total protein, and activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POX). Proline and pod fibers were decreased in parallel with increasing the N rate, while water use efficiency (WUE) was improved with increasing the rate of N supplements up to 100% or 110% of the recommended dose.