Characterization of Cob Rind Biochar and Its Effect on Primary Nutrient Content and their Uptake by Finger Millet (Eleusine coracana)

Biochar has gained attention as a sustainable soil amendment for improving soil fertility and nutrient use efficiency. The present study evaluated the physicochemical characteristics of maize cob rind biochar and its effect on primary nutrient content and uptake by finger millet (Eleusine coracana). Biochar was produced through controlled pyrolysis and characterized for pH, electrical conductivity, bulk density, organic carbon, and nutrient composition. A pot experiment was conducted to assess the influence of biochar application alone and in combination with farmyard manure (FYM) on nitrogen, phosphorus, and potassium content and uptake by finger millet. Results indicated that cob rind biochar possessed favorable properties such as alkaline pH, high organic carbon content, and appreciable nutrient concentrations. Combined application of biochar and FYM significantly enhanced N, P, and K concentration and uptake in grain and straw compared to the recommended fertilizer and FYM treatment alone. The highest nutrient uptake and dry matter production were recorded with biochar application at 4 t ha⁻¹ along with 100% recommended FYM. Improved nutrient uptake was attributed to enhanced nutrient retention and improved soil conditions. The study concludes that cob rind biochar, when integrated with organic manure, can effectively improve nutrient uptake and promote sustainable nutrient management in finger millet cultivation.