Biochar and poultry manure application effects on selected soil chemical properties and bioaccumulation of heavy metals in maize plant cultivated on degraded soils

Abstract

With the rapid development of industrialization and overpopulation, a significant number of heavy metals have been produced and entered the soil through anthropogenic (illegal mining) interference, and has become an issue of global focus. Soil samples for this study were collected in degraded farmland in Amagu, Abakaliki, Nigeria. The study evaluated the effect of composted poultry manure and biochar on heavy metals (Lead, Copper, and Zinc) in degraded soil and its bioaccumulation in maize plants. Biochar from three feedstocks were pyrolyzed at 42⁰C, while poultry manure from battery cage system was composted for 90 days before application. The study was a 4 × 2 factorial experiment in a completely randomized design. The soil's physical and chemical properties were analysed before treatment. The application of Composted poultry manure (CPM) and biochar sources reduced the acidity of the soil and recorded a significant increase in the organic carbon content. After harvest, Pb still exceeded the Food and Agricultural Organization (FAO) permissible limit of 100 mg/kg in Agricultural soils, but reduced significantly in the root region. CPM showed a significant (P≤0.05) increase by 33 % of the amount of Pb in the shoot after harvesting. Significant increases were recorded in the level of copper in the shoot across the biochar treatments. About 140 % reduction of Zinc in the soil was recorded after composted poultry manure was applied. The application of the organic treatments varied in their effects on different elements and plant bioaccumulation mechanisms. The amount of Pb in the root and shoot reduced after the application of biochar and poultry manure.