Does Biochar Improve Acidic Soil Physical Properties and Crop Yield Under Varying Climatic and Soil Conditions? A Global Comprehensive Meta‐Analysis
Muhammad Aurangzeib, Shaoliang Zhang, Sihua Yan, Zhimiao Wei, Haijun Zhang, Xiaoguang Niu, Pengke Yan
Abstract
ABSTRACT The ability of biochar to improve soil's physical properties and change the crop yield in acidic soil is still debated. Additionally, the factors influencing biochar's performance are not well understood. This meta‐analysis, combined with random forest regression, structural modelling and partial Mantel test, analysed 1889 paired observations based on 65 peer‐reviewed articles indexed in Web of Science. The findings indicated that biochar application in tropical climate zones with acidic soil (pH < 7) over < 3 years typically increases the soil porosity (23%), mean weight diameter (MWD) (46%) and yield (38%) while decreasing the soil bulk density (SBD) (−19%). In addition, biochar in continental climatic zones increased acidic soil field capacity (15%) and plant available water (47.3%). The minimum biochar's effect on soil's physical properties and yield was observed in soil pH < 5. Biochar produced from wood feedstocks, pyrolysed at 450°C–500°C, pH range of 7–8, application rates > 40 t ha −1 , carbon > 60%, nitrogen > 1.5%, ash < 10% and a bulk density of < 0.2 g·cm −3 was highly effective. Among factors, mean annual temperature (MAT) was relatively the most important key factor determining the effect of biochar on SBD (21%), MWD (15%), hydraulic conductivity (22%) and yield (15%). Therefore, the biochar application in acidic soil (pH 5–6), having initial soil organic carbon 0.87%–1.74%, coarse texture and tropical climatic zones (MAT 25°C–32°C, mean annual precipitation 800–2450 mm), is ideal for improving soil's physical properties and yield. Overall, the study emphasises the biochar potential to improve acidic soil's physical properties and yield based on varying soil and climatic conditions for better agricultural management practices.