Carbon Sequestration in Agroforestry Systems

• Published in: Advances in Agronomy Vol. 108; pp. 237 - 307
• Main Authors: Ramachandran Nair, P.K., Nair, Vimala D., Mohan Kumar, B., Showalter, Julia M.
• Format: Book Chapter Journal Article
• Language: English
• Published: United States Elsevier Science & Technology 2010; Elsevier BV
• Subjects: Agricultural science; Agroforestry; Agronomy; Carbon sequestration; Crop husbandry; Developing countries; Ecological conditions; Environmental conditions; Farming systems; Forestry; Land use; LDCs; Organic carbon; Pasture; Planting density; Soil profiles; Soil science, sedimentology; Species richness; Trees
• ISBN: 9780123810311; 0123810310
• ISSN: 0065-2113; 2213-6789
• DOI: 10.1016/S0065-2113(10)08005-3

Agroforestry—the practice of growing trees and crops in interacting combinations—is recognized worldwide as an integrated approach to sustainable land-use. It is estimated to be practiced over 1 billion hectares in developing countries, and to a lesser extent in the industrialized countries. Agroforestry systems (AFSs) are believed to have a higher potential to sequester carbon (C) because of their perceived ability for greater capture and utilization of growth resources (light, nutrients, and water) than single-species crop or pasture systems. The estimates of C stored in AFSs range from 0.29 to 15.21Mgha−1yr−1 aboveground, and 30 to 300MgCha−1 up to 1-m depth in the soil. Recent studies under various AFSs in diverse ecological conditions showed that tree-based agricultural systems, compared to treeless systems, stored more C in deeper soil layers near the tree than away from the tree; higher soil organic carbon content was associated with higher species richness and tree density; and C3 plants (trees) contributed to more C in the silt-+clay-sized (<53μm diameter) fractions—that constitute more stable C—than C4 plants in deeper soil profiles. The extent of C sequestered in AFSs depends to a great extent on environmental conditions and system management. Trading of the sequestered C is a viable opportunity for economic benefit to agroforestry practitioners, who are mostly resource-poor farmers in developing countries. However, more rigorous research results are required for AFSs to be used in global agendas of C sequestration.