Tree species composition, diversity and soil organic carbon stock in homegardens and shifting cultivation fallows of Mizoram, Northeast India

Abstract

We examined tree species diversity and soil organic carbon (SOC) at different soil depth intervals (0–20, 20–50, 50–80, and 80–100 cm) of homegardens (HGs) and shifting cultivation fallows (SCFs) of Mizoram, Northeast India. Total tree species encountered in the sampled HGs and SCFs plots were 86 and 50 respectively. Significant differences (p < 0.05) in tree diversity and basal area was observed between different age categories of both land use systems. Tree diversity was inversely related to the age of homegardens, whereas a positive correlation (significant at p < 0.05) was observed with the increasing age in case of shifting cultivation fallows. On an average, SOC content in the older systems were significantly higher (p < 0.05) than the younger systems and small HGs had discernibly higher (p < 0.05) SOC than the large HGs. Highest SOC content was found in 0–20 cm and decreased with increasing soil depth. At 1 m soil depth, SOC stock was 183.42 and 123.24 Mg C ha− 1 in HGs and SCFs respectively. Values of SOC content were higher in HGs than the SCFs as a result of higher tree species composition and density. The study demonstrate that both HGs and SCFs, being tree based systems can sequester carbon and contribute to climate change mitigation.