Evaluation of Different Biochar Sources on Growth, Yield and Soil Fertility of Okra and Brinjal in Inceptisol from Odisha : A Pot Study

Declining soil organic carbon and nutrient imbalances in Inceptisols of eastern India have reduced productivity of intensive vegetable systems under sole chemical fertilizer use. However, limited information exists on the comparative effectiveness of different biochar sources integrated with farmyard manure (FYM) and recommended dose of fertilizers (RDF) for improving soil fertility and yield of okra and brinjal. In this context, a pot experiment was conducted during 2021–2022 at the ICAR–Indian Institute of Soil Science (IISS), Bhopal, India, to evaluate the effect of different biochar sources and application rates, alone and in combination with FYM and RDF on growth, yield, and soil fertility of okra and brinjal grown in an Inceptisol soil collected from Belpada, Odisha. The experiment was laid out in a Completely Randomized Design (CRD) with eleven treatments replicated four times, involving two biochar sources {crop residue biochar (CRB) of groundnut, mustard, and rice husk and mixed wood biochar (WCB) of Prosopis juliflora and coconut husk} applied at 0, 4, and 8 g kg⁻¹ soil, with and without FYM (5 g kg⁻¹ soil) and (RDF). Results revealed that integrated application of biochar, FYM, and RDF significantly (p < 0.05) improved plant height and yield of both the crops over the control (0) and fertilizer-alone treatments. The treatment crop residue biochar @ 8 g kg⁻¹ soil + FYM @ 5 g kg⁻¹ soil + RDF (F CRB M ) consistently recorded the highest yields of 1 8 5 okra (182.4 g pot-1) and brinjal (262.5 g pot-1), resulting in nearly two-fold higher fruit yield of okra and three- to four-fold higher fruit yield of brinjal compared to the control across both years. This treatment also improved N, P, and K uptake substantially, with N uptake increasing more than four fold in okra and over twofold in brinjal, accompanied by marked increases in P and K uptake across both crops. Biochar application moderated soil reaction, raising soil pH from near-neutral control levels (~7.26) to ~7.64, indicating its liming potential, while soil organic carbon (SOC), available P, and available K increased by 114%, 170%, and 27%, respectively, under integrated treatments. Unlike earlier studies focusing on single biochar sources or short-term responses, this study provides a comparative assessment of crop residue and mixed biomass biochars at graded rates under integrated application with FYM and RDF, highlighting their cumulative effects. The findings offer new insights into optimized biochar-based nutrient management strategies for sustaining vegetable productivity and soil fertility in Inceptisols. Although it is just a pot study but it concludes that biochar alone is insufficient, but its integration with FYM and RDF, particularly crop residue biochar at higher rates, is an effective and sustainable strategy for enhancing vegetable productivity and soil fertility in Inceptisol soils.