Combined application of poultry litter biochar and NPK fertilizer improves cabbage yield and soil chemical properties

Low soil fertility is a major problem limiting peri-urban vegetable production in the Kumasi metropolis. This study was conducted to assess the effects of poultry litter biochar (PLB) and NPK fertilizer application on soil chemical properties and the yield of cabbage. Twelve treatments (control, 100% NPK, 50% NPK, 2.5 t ha−1 PLB, 2.5 t ha−1 PLB + 50% NPK, 2.5 t ha−1 PLB + 100% NPK, 5 t ha−1 PLB, 5 t ha−1 PLB + 50% NPK, 5 t ha−1 PLB + 100% NPK, 7.5 t ha−1 PLB, 7.5 t ha−1 PLB + 50% NPK, and 7.5 t ha−1 PLB + 100% NPK) were evaluated under field conditions in a randomized block design with three replications. Combined application of PLB and NPK fertilizer improved the soil chemical properties, growth, and yield of cabbage relative to the control and sole PLB treatments. Application of 5 t ha−1 PLB + 50% NPK increased the soil pH, soil organic carbon, available phosphorus, and cation exchange capacity by 26.6, 41.4, 296, and 78.7%, respectively, relative to the control. Moreover, 5 t ha−1 PLB + 50% NPK increased the cabbage yield by 73% compared with the control. This study concludes that PLB and NPK fertilizers can be applied to improve the soil chemical properties and yield of cabbage.