Climate-smart agriculture represents a sustainable approach that promotes food production and soil fertility while reducing greenhouse gas (GHG) emissions. Within this framework, organic agriculture serves as a vital strategy as it increases soil carbon, lowers GHG emissions, and supports long-term sustainability. Biochar is a key innovation in this context, enhancing soil carbon sequestration and contributing to GHG mitigation. However, despite its role in soil conditioning, biochar was found to have some limitations related to improving soil nitrogen. Hence, this study was initiated with the aim of developing biochar-formulated fertilizer to complement what biochar lacks and evaluating it on model winter and summer crops. A Randomized Complete Block Design (RCBD) experimental setup was employed, with 17 treatments (including four organic amendments, twelve formulated fertilizers, and a control), each replicated three times. The research followed a two-phase experimental design: an initial screening during the winter season of 2024 using mustard greens as a winter model crop, followed by a summer 2025 trial with sorghum as a summer model crop. Measurements included soil parameters, plant growth performance, and soil GHG emissions (nitrous oxide, N2O), methane (CH4), and carbon dioxide (CO2), analyzed using state-of-the-art methodologies. Among the 17 treatments, five (T6, T7, T8, T15, and T17) demonstrated notable improvements in soil nitrogen content, plant growth, and emission reduction. These five amendments were subsequently compared to standard NPK fertilizer during the summer trial. The findings demonstrated that treatments T7 (40% biochar, 20% chitosan, 40% chicken manure) and T17 (75% biochar, 25% cow manure) markedly improved sorghum growth, yielding results comparable to those observed with the positive control group that received NPK fertilizer. It is evident that these two formulations are substantially mitigating GHG emissions from the soil and improving crop performance. This study suggests that these two biochar-based formulations should be tested on larger farms and with both winter and summer crops to determine their effectiveness and potential for broader use.