Residual Nutrients Of Some Horticultural Crops Waste Biochars In An Alfisol

The ability of a fertilizer to supply nutrients beyond a cropping season is as important as the nutrient composition. A pot experiment was conducted to compare residual nutrients of five horticultural crop wastes biochar after cropping with Corchorus olitorius, viz: locust bean pod (LB), Plantain Stalk (PtS), Plantain Peel (PtPe), Pineapple Pulp (PaPu) and Pineapple Pulp (PaPe). The biochars at 5 kg ha-1 were thoroughly mixed with 5 kg soil (Alfisol), Urea (60 kg N ha-1) and Murate of Potash (30 kg K ha-1) and arranged in a completely randomized design with three replicates. The control was without biochar. Corchorus olitorius seeds were sown in the pots after watering to field capacity and subsequently watered as required. Soil samples were collected from each pot at four weeks after sowing (4 WAS), air dried and analyzed for the pH, organic carbon (OC), total nitrogen (N), available phosphorus (Av. P), exchangeable bases (Ca, Mg, K and Na) and some micronutrients (Mn, Fe, Zn and Cu). Data were subjected to analysis of variance (ANOVA) while Duncan Multiple Range Test was used to separate treatment means at α0.05. There were significant differences among soil residual nutrients. Highest pH value was observed on PtS and PtPe, residual organic carbon and nitrogen on LB and PtPe, available phosphorus on LB, K on PtS, Ca, Mg, Mn, Fe and Cu on PaPe while Zn on PtPe. The soil residual nutrients of the biochars showed their ability to supply nutrients beyond a cropping season for Corchorus olitorius.