TITLE:
Implementing Reduced Tillage, Residue Retention and Nitrogen Rates on CO₂ and CH₄ Fluxes in Irrigated Wheat on Subtropical Floodplain Soils
AUTHORS:
Rafeza Begum, Mohammad Mokhlesur Rahman, Md. Mahbubul Alam, Md. Khyrul Islam Bashar, Md. Hafizul Islam, Abdul Awal, Md. Afnan Hossain Chy, Shah Mohammad Kamrul Hasan
KEYWORDS:
Carbon Dioxide Emissions, Methane Emission, Nitrogen Rate, Tillage, Residue Retention
JOURNAL NAME:
Open Access Library Journal,
Vol.13 No.9,
September
9,
2026
ABSTRACT: Quantifying carbon (C) sequestration in soils is necessary to help better understand the effect of agricultural practices on the C cycle. The estimated contribution of agricultural carbon dioxide (CO2) and methane (CH4) to global warming potential (GWP) has a wide range. The underlying causes of this huge uncertainty are the difficulties in predicting regional CO2 and CH4 losses due to lack of experimental evidence on CO2 and CH4 emissions and associated drivers. The CH4 and CO2 emissions were measured in irrigated wheat in a subtropical floodplain soils which have been under two soil disturbance levels (strip vs. conventional tillage; ST vs. CT being both with 30% residue retention) and three N fertilizer rates (60%, 100% and 140% of the recommended N fertilizer dose, RD) in an annual wheat (Triticum aestivum)-mungbean (Vigna radiata)-rice (Oryza sativa L) for seven consecutive years. The highest CH4 and CO2 emission peak was observed on day 3 after urea application in both tillage systems, except for CO2 flux in CT. Nitrogen fertilizer application rate significantly influenced mean and cumulative CH4 and CO2 fluxes. At the optimum dose of N fertilizer, both CH4 and CO2 fluxes decreased, except for CH4 under ST. CO2 emissions were significantly higher under minimum (60% of RD) fertilizer application in both tillage systems. Soil microbial biomass carbon (MBC), organic carbon (SOC), particulate organic carbon (POC), permanganate oxidisable carbon (POXC), and basal respiration (BR) were significantly higher in ST which were negative and significantly correlated with CO2. However, POC and POXC were positively and significantly correlated with CH4 emission.