Biochar’s effect on crop productivity and the dependence on experimental conditions—a meta-analysis of literature data

BACKGROUND AND AIMS: For the last decade, there has been an increasing global interest in using biochar to mitigate climate change by storing carbon in soil. However, there is a lack of detailed knowledge on the impact of biochar on the crop productivity in different agricultural systems. The objective of this study was to quantify the effect of biochar soil amendment (BSA) on crop productivity and to analyze the dependence of responses on experimental conditions. METHODS: A weighted meta-analysis was conducted based on data from 103 studies published up to April, 2013. The effect of BSA on crop productivity was quantified by characterizing experimental conditions. RESULTS: In the published experiments, with biochar amendment rates generally