Genotype-Driven Carbon Sequestration And Soil Fertility Restoration In Coastal Agroforestry Systems: A Mechanistic Evaluation Of Nutrient * Genotype Interactions

Abstract Coastal agroecosystems are critical yet fragile carbon sinks, often limited by severe soil degradation and nutrient leaching. While agroforestry is a proven strategy for soil restoration, the role of intercrop genotype-level variation in regulating system-wide carbon sequestration remains poorly understood. This study evaluated a coastal guava ( Psidium guajava L.) agroforestry system in Odisha, India, to determine how the interaction between three brinjal ( Solanum melongena L.) genotypes and graded nutrient regimes influences carbon partitioning and soil health. Our results demonstrate that carbon sequestration is governed by a significant Genotype * Nutrient interaction. The ‘Utkal Madhuri’ genotype emerged as a superior biological regulator, maximizing total system carbon stocks to 59.49 t ha −1 and sequestration rates to 19.83 t ha −1 yr −1 . Simultaneously, optimized fertilization (200:50:50 kg ha −1 N:P 2 O 5 :K 2 O) increased soil organic carbon to 0.47% and significantly improved bulk density without inducing soil acidification. These findings reveal that intercrop genetic selection is as vital as chemical inputs for climate mitigation. Integrating high-performing genotypes with optimized nutrient regimes provides a scalable framework for restoring fertility and enhancing carbon sinks in vulnerable coastal landscapes.