Dynamics of Biochar on Zinc and Iron Bioaccumulation in Groundnut Grown on Contaminated Soils in Amagu, Abakiliki Ebonyi State, Nigeria

Abstract

The study evaluated the influence of biochar on heavy metal accumulation in the pods of groundnut cultivated in heavy metal-contaminated soils in Amagu, Abakiliki Ebonyi State. The soil samples were collected from farmlands adjacent to the mining sites located in Amagu, in Abakaliki Local Government Area of Ebonyi State. Bulked soil samples were air-dried and sieved using a 5mm sieve. 10 kg of air-dried soil was put in a 12-liter bucket; water was applied to moisten the soil at 60% field capacity. The experiment was a completely randomized design. Biochar was applied at 0, 20, 40, 60, and 80 t/ha. Groundnut seeds were planted two (2) weeks after biochar application. Soil samples were analyzed for physical and chemical properties before planting and after harvest. Data collected were subjected to analysis of variance (ANOVA) using GenStat. The results observed that biochar applied had different responses to Zn and Fe accumulation across the entire plant parts. It also revealed that the amount of Zn in soil ranged between 167mg/kg to 1750mg/kg, while Zn in shoot ranged between 67mg/kg to 1133mg/kg, Zn amount in the pod of groundnut ranged between 102mg/kg to 1482mg/kg, the results on Zn content in seeds of groundnuts ranged from 283mg/kg to 1586mg/kg. It was observed from the results, that concentration of Zn increased as biochar rates increased. The Fe concentration in the pod ranged from 1601mg/kg to 5668mg/kg, and the result on Fe content in seed ranged from 1705mg/kg to 11537mg/kg. Bioaccumulation factor (BAF) and Translocation factor (TF) were ≥1, thereby classifying groundnut as an effective hyperaccumulator. The application of this research finding would go a long way in improving food safety and human health.