This chapter explores agricultural carbon (C) trading systems, highlighting their societal value in addressing climate change and promoting sustainable land use. It discusses the potential of C markets to encourage C farming through financial incentives and market-based solutions. Core elements of the C credit process such as project design, measurement, verification, and issuance are outlined, along with the distinction between regulatory and voluntary C markets. Challenges including low credit prices, additionality, permanence, leakage, and verification issues are critically examined. The chapter concludes with strategies such as Payment for Ecosystem Services, supportive policy frameworks, and innovation to enhance farmer participation and advance both environmental and societal goals.