Amending triple superphosphate with chicken litter biochar improves phosphorus availability

Abstract

The reaction of H2PO42- and HPO4- with Al and Fe in acid soils to form a precipitate reducesP availability. Chicken litter biochar has been used to improve soil P availability for maizeproduction but with limited information on optimum rates of biochar and TripleSuperphosphate (TSP) to increase P availability. This study determined the optimumamount of chicken litter biochar and TSP that could increase P availability. Different ratesof chicken litter biochar and TSP were evaluated in an incubation study for 30, 60, and 90days. Selected soil chemical properties before and after incubation were determined usingstandard procedures. Soil pH, total P, available P, and water soluble P increased intreatments with 75% and 50% biochar. Total acidity, exchangeable Al3+, and Fe2+ weresignificantly reduced by the chicken litter biochar. The chicken litter biochar alsoincreased soil CEC and exchangeable cations (K, Ca, Mg and Na). The use of 75% and 50%of 5 t ha-1 biochar with 25% TSP of the existing recommendation can be used to increase Pavailability whilst minimizing soil Al and Fe content. This rates can be used to optimizechicken litter biochar and TSP use in acid soils for crop production especially maize andshort term vegetables.