Effect of nutrient management on soil organic carbon fractions and sequestration under bamboo plantation

Abstract:

An investigation was conducted to evaluate the influence of integrated nutrient management on soil organic carbon fractions and soil carbon sequestration under a Bambusa balcooa plantation. The field experiment was laid out in a randomized block design comprising six graded fertilizer treatments, ranging from 100 % to 150 % of the recommended dose of fertilizer, applied in combination with a bio-decomposer to facilitate in-situ decomposition of leaf litter. The results indicated that graded fertilizer applications significantly enhanced all oxidizable soil carbon fractions. The highest fertilizer treatment consistently outperformed all other treatments, recording the maximum values for very labile carbon (5.34 g kg⁻¹), labile carbon (2.50 g kg⁻¹), less labile carbon (2.02 g kg⁻¹) and non-labile carbon (3.72 g kg⁻¹). Consequently, the active and passive carbon pools reached their highest values under the maximum fertilizer dose. Improved soil carbon stabilization was reflected in the carbon management index, which increased substantially from 177.69 in the lower fertilizer treatment to 269.56 in treatment T₆. Furthermore, enhanced carbon stabilization led to superior below-ground carbon capture capacity. The highest soil carbon stock (52.45 t ha⁻¹) and a maximum soil carbon sequestration rate of 7.06 t ha⁻¹ yr⁻¹ were recorded under the highest fertilizer treatment. It is concluded that the application of 150 % of the recommended fertilizer dose, integrated with leaf litter decomposition, is an effective nutrient management strategy for improving soil carbon quality, enhancing stable carbon pools and maximizing long-term soil carbon sequestration in bamboo plantations.