Utilization of biochar in rainfed farming systems: A meta-analysis

Biochar application in rainfed farming can increase crop productivity by improving the water retention capacity and nutritional status of rhizosphere. This meta-analysis was carried out to assess the quantitative effects of biochar addition to the soil on the productivity of crops under rainfed conditions. The results indicated that increments in plant biomass and grain yield production of cereal crops in response to biochar application under rainfed conditions were higher than in legume crops. Low-temperature pyrolyzed biochar (<= 500 degrees C) with high carbon (>50 %) and nitrogen (>1 %) contents and pH <8 was more effective in enhancing biomass and grain production, compared to other types of biochar. The ideal biochar application rate to improve biomass and grain yield of plants under rainfed conditions was about 20-40 tons ha-1. In general, biochar can increase plant biomass (by about 13 %) and grain yield (by about 14 %) of crops under rainfed conditions.