Impact of Carbon-Based Biochar Application on Red Pepper Yield and Soil Carbon Sequestration

This study investigates the impact of biochar derived from red pepper by-products on crop growth, soil carbon storage, and agricultural productivity, with a focus on adapting red pepper cultivation to climate change. The experiment was conducted over two years at the Chungcheongnam-do Agricultural Research and Extension Services in South Korea. Biochar was applied at varying rates based on its carbon content (0.0, 2.5, 5.0, 10.0 Mg C ha⁻¹) to evaluate its effects on soil properties and red pepper yield. The biochar, produced using a Top-Lit Updraft (TLUD) gasification system, possessed a carbon content of 68.7% and a high pH of 10.3. The results demonstrated that biochar application significantly enhanced red pepper growth and yield, with the highest total yield observed at the maximum application rate (BC_10.0, 10.0 Mg C ha⁻¹). However, yield efficiency (yield increase per Mg of biochar C) was highest at the lowest application rate (BC_2.5, 2.5 Mg C ha⁻¹). Soil analysis revealed that biochar amendment improved soil pH, electrical conductivity (EC), and total carbon content. Although the standard soil analysis protocol (<2 mm sieving) resulted in an underestimation of soil carbon stock by excluding coarse biochar particles, the persistence of these coarse fractions confirms the high physical stability of the biochar, validating its potential as a long-term carbon sink. These findings provide a scientific basis for optimized biochar application strategies that balance productivity with carbon sequestration.