Ghimire, Rajan;Lamichhane, Sushil;Acharya, Bharat Sharma;Bista, Prakriti;Sainju, Upendra Man

New Mexico State Univ, Agr Sci Ctr, Clovis, NM 88101 USA;Nepal Agr Res Council, Soil Sci Div, Khumaltar, Nepal;Oklahoma State Univ, Dept Nat Resource Ecol & Management, Stillwater, OK 74078 USA;USDA ARS, Northern Plains Agr Res Lab, Sidney, MT 59270 USA;Oregon State Univ, Columbia Basin Agr Res Ctr, Pendleton, OR 97801 USA

carbon mapping;carbon sequestration;crop residue;no-tillage;rice-wheat system

Soil organic carbon (SOC) sequestration is one of the major agricultural strategies to mitigate greenhouse gas (GHG) emissions, enhance food security, and improve agricultural sustainability. This paper synthesizes the much-needed state of-knowledge on the effects of tillage, crop residue, and nutrient management practices on SOC sequestration and identifies potential research gap, opportunities, and challenges in studying SOC dynamics in rice (Otyza sativa L.)-based cropping systems in South Asia, mainly in Bangladesh, Bhutan, India, Nepal, Pakistan, and Sri Lanka. Improved management practices such as reduced- and no-tillage management, nitrogen (N) fertilizer and farmyard manure (FYM) application, and crop residue addition can improve SOC accumulation. Positive effects of no-tillage, crop residue addition, N addition through manure or compost application, and integration of organic and chemical fertilizers on SOC accumulation in rice -based cropping systems have been documented from South Asia. However, limited data and enormous discrepancies in SOC measurements across the region exist as the greatest challenge in increasing SOC sequestration and improving agricultural sustainability. More research on SOC as influenced by alternative tillage, crop residue, and nutrient management systems, and development of SOC monitoring system for existing long-term experiments will advance our understanding of the SOC dynamics in rice -based cropping systems and improve agricultural system sustainability in South Asia.