Changes in soil carbon stocks across the Forest-Agroforest-Agriculture/Pasture continuum in various agroecological regions: A meta-analysis

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2018-11, Vol.266, p.55-67
• Main Authors: Chatterjee, Nilovna, Nair, P.K.Ramachandran, Chakraborty, Saptarshi, Nair, Vimala D.
• Format: Article
• Language: English
• Subjects: Agricultural land; Agricultural practices; Agriculture; Agroecological region; Agroforestry; Arid regions; Carbon; Carbon sinks; Climate change; Climate-change mitigation; Data points; Forestry; Forests; Greenhouse effect; Greenhouse gases; Land management; Land use; Land-use systems; Meta-analysis; Mitigation; Mixed-effects model; Organic carbon; Organic soils; Pasture; Semi arid areas; Semiarid lands; Soil C stocks; Soil depth; Soil layers; Trees; Tropical environments
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2018.07.014

[Display omitted] •Meta-analysis had 858 data points from 78 published studies across 30 countries.•Focused on SOC (soil organic carbon) stock under agroforestry systems (AFS).•The Agroforest aged between 10–20 years had higher SOC stock.•Higher SOC stocks under AFS across all regions except for the temperate region. The contribution of agroforestry systems (AFS) to enhance soil organic carbon (SOC) storage in soil layers due to the presence of deep tree roots are of interest in the context of promoting carbon sinks and greenhouse gas mitigation. To quantify the relative soil C contribution from trees in agroforestry systems (AFS), this study assessed the reported differences in SOC stocks under agroforestry systems in comparison with other land-use systems (Agriculture, Forestry, Pasture, or Uncultivated Land) in various soil-depth classes in four agroecological regions (arid and semiarid, ASA; lowland humid tropics, LHT; Mediterranean, MED; and temperate, TEM) around the world. Using mixed-effect models and a meta-analytical approach, we synthesized data from 78 peer-reviewed studies that generated 858 data points (sites) on SOC stock under various AFS practiced globally. Comparing Agroforest vs. Agriculture or Agroforest vs. Pasture, SOC stocks under AFS were higher by +27% in the ASA region, +26% in LHT, and +5.8% in TEM, but –5.3% in the TEM in the 0–100 cm soil depth. The Agroforest aged between 10–20 years had higher SOC stock than newly established, as well as