Soil carbon stocks and land use change: a meta analysis

TLDR

Land‑use change impacts on soil carbon stocks are a key concern for global greenhouse‑gas mitigation, but limited data and diverse methods mean current conclusions are provisional and warrant further study. This paper reviews 74 published studies to investigate how land‑use changes affect soil carbon stocks. The authors conduct a meta‑analysis of these data to quantify the magnitude of soil carbon changes across different land‑use transitions. The meta‑analysis shows that converting pasture or native forest to plantations or crops generally reduces soil carbon (by 10–59%), while converting native forest or crops to pasture or secondary forest increases it (by 8–53%); broadleaf plantations have little effect, whereas pine plantations lower soil carbon by 12–15%.

Abstract

Abstract The effects of land use change on soil carbon stocks are of concern in the context of international policy agendas on greenhouse gas emissions mitigation. This paper reviews the literature for the influence of land use changes on soil C stocks and reports the results of a meta analysis of these data from 74 publications. The meta analysis indicates that soil C stocks decline after land use changes from pasture to plantation (−10%), native forest to plantation (−13%), native forest to crop (−42%), and pasture to crop (−59%). Soil C stocks increase after land use changes from native forest to pasture (+ 8%), crop to pasture (+ 19%), crop to plantation (+ 18%), and crop to secondary forest (+ 53%). Wherever one of the land use changes decreased soil C, the reverse process usually increased soil carbon and vice versa . As the quantity of available data is not large and the methodologies used are diverse, the conclusions drawn must be regarded as working hypotheses from which to design future targeted investigations that broaden the database. Within some land use changes there were, however, sufficient examples to explore the role of other factors contributing to the above conclusions. One outcome of the meta analysis, especially worthy of further investigation in the context of carbon sink strategies for greenhouse gas mitigation, is that broadleaf tree plantations placed onto prior native forest or pastures did not affect soil C stocks whereas pine plantations reduced soil C stocks by 12–15%.