Effects of Biochar on Soil Fertility and Crop Yields: Experience from the Southern Highlands of Tanzania

Abstract

The world’s agricultural production is declining due to severe loss of soil fertility through natural processes or because of human activities. Biochar has been identified as a potential soil amendment to regain its fertility and increase crop productivity. This study aimed to assess the effects of biochar on soil nutrients and crop yields in the southern highlands of Tanzania. Data were collected through key informant and household interviews, and from sampling of soils in coffee farms where biochar of maize cobs origin was incorporated at the rate of 3 t ha^-1. Purposive sampling approach was deployed to identify the villages in which farmers have been incorporating biochar in farms. A total of 172 households, 30 key informants, and 12 top and subsoil samples were involved in this study. Quantitative data were analyzed using SPSS version 20, and excel spreadsheet was used for descriptive results and relationships. The findings revealed that biochar significantly increased soil pH, iron (Fe), organic carbon (OC), cation exchange capacity (CEC) and exchangeable bases (potassium-K, magnesium-Mg). T - tests showed significant increase of soil nutrients in biochar treated soils. In addition, biochar increased coffee and maize yields from 1 t ha^-1 to 3 t ha^-1.

Keywords: Biochar; Soil Nutrients; Food Security; Resilience; Adaptation