Biochar for Wastewater Treatment and Soil Improvement in Irrigated Urban Agriculture: Single and Combined Effects on Crop Yields and Soil Fertility

Urban Farm DB summary

This study evaluated the agronomic and soil fertility effects of using municipal wastewater or anaerobically treated wastewater for irrigation and applying biochar to a soil from the Guinea savanna agroecological zone of Ghana. In a pot trial, lettuce and carrot were grown on soil mixed with raw biochar, water-washed biochar, or biochar used as wastewater filter material at 20 t ha−1, and irrigated with untreated municipal wastewater, anaerobically treated wastewater, or clean water. Results indicated higher crop growth and yields (up to 90% increase) with untreated and anaerobically treated wastewater than clean water, with anaerobically treated wastewater being more beneficial than untreated wastewater (up to 10% increase). Combining raw biochar with anaerobically treated wastewater increased pH, CEC, and P availability in the highly weathered acidic soil.