Evaluating the impacts of irrigation and fertilization on soil CO2 emissions and cotton yields

Cotton is an important commercial crop in Texas. The application of irrigation and fertilizer has a significant influence on cotton production and environmental effects, including greenhouse gas emissions (GHG) and carbon sequestration. The study addresses a critical gap in current research by examining the integrated effects of nutrient and irrigation management on yields and GHG during cotton cultivation. Three different nitrogen treatments were evaluated: low (19.6 kg N/ha), moderate (39.2 kg N/ha), and high (78.5 kg N/ha). Irrigation treatments included plots with no irrigation, moderate irrigation, and high irrigation rates, and soil sensors were installed on each plot. Soil CO2 emission was measured using Soil-CO2 Flux Chambers, and cotton yield was taken. Cotton yield increased by 59% under high irrigation compared to moderate irrigation, and by 97% relative to no irrigation. Different N levels showed no significant impact (p = 0.773) on the cotton yield. Cotton yield and CO2 emissions were significantly higher (p < 0.05) under the high irrigation level, indicating that increased water availability facilitated favorable conditions for microbial decomposition and root respiration. The daily average CO2 emission varied from 86.3 kg CO2/ha/day under no irrigation to 132.9 kg CO2/ha/day under high irrigation during the measurement period. Moderate irrigation combined with moderate nitrogen fertilization yields 670.3 kg/ha of cotton, offering the best balance between yield optimization and CO2 emission reduction. These findings underscore the importance of water management in optimizing cotton yield and suggest its influence on productivity compared to variations in N fertilizer application.