Bone biochar as a soil amendment for enhancing Okra (Abelmoschus esculentus) production in degraded bare, and eroded ultisols

Bone biochar is produced through the pyrolysis of cow bones in a limited-oxygen environment. It has been reported to be rich in essential soil nutrients, thereby enhancing the soil’s capacity for crop production. This study evaluates the effects of cow bone biochar on the soil health of degraded bare and eroded ultisols and its influence on okra production. A six-week greenhouse incubation study was conducted. Eroded and bare soils were obtained from a terrace at the field erosion experimental plots at the linkage and a motor park of the Faculty of Agriculture, University of Nigeria, Nsukka. Samples were collected during the peak of the rainy season (July 2024). Cow bone biochar pyrolyzed at 250–300 °C was applied at the rates of 0, 20, 40, and 60 g/4kg soil (w/w). The experimental design was completely randomized with three replicates. After the six weeks of incubation, Okra seeds were sown in the pots. At the end of the experiment, physicochemical properties of the bare and eroded soils, as well as Okra growth and yield components, were analysed. The eroded soil’s aggregate stability, MWD, base saturation, and exchangeable acidity were 109, 29.3, 26.8, and 33.9%, respectively, significantly (P ≤ 0.05) higher than those of the bare soil. In contrast, the bare soil had 55.1, 92.9, 8.3, 14.6, and 53.7% higher hydraulic conductivity (Ksat), available phosphorus, total nitrogen, CEC, and organic carbon, respectively, than the bare soils. The growth and yield of okra were significantly (P ≤ 0.05) higher in bare soils than in eroded soils. The coefficient of determination (R2) of soil properties and other growth and yield parameters of okra on fruit weight was relatively high at 91.7% and 93.9% on bare and eroded soils, respectively. The findings indicate that bone biochar significantly enhanced the fertility of degraded ultisols, thereby influencing okra production, with the most pronounced effects observed in bare soils compared to eroded soils.