Effect of Biochar on CO2 Sequestration and Productivity of Pearl Millet Plants Grown in Saline Sodic Soils

Abstract

The use of biochar to increase the soil carbon sequestration is a vital tool to reduce greenhouse gas emissions. Biochar was added to pearl millet (Pennisetum glaucum L.) to investigated its role in carbon sequestration and increasing the plant productivity. In these 2-year filed studies, biochar was added to a saline sodic soil at five rates: 0, 5 (BC5), 10 (BC10), 15 (BC15), and 20 (BC20) ton ha−1. Biochar raised the soil organic carbon and improved the availability and uptake of N, P, and K compared with the non-amended soil. BC5, BC10, BC15, and BC20 increased the forage yield by 36, 45, 27, and 18%, respectively, above the control in the first year and by 45, 65, 35, and 25%, respectively, in the second year. Biochar significantly minimized the proline, phenolic compounds, Na+, and Cl− in the leaf tissue of pearl millet. BC20 increased CO2 emissions by 15, 13, and 10%, respectively, compared with the control in the first, second, and third cuts. Biochar had a positive effect on increasing CO2 emissions from saline sodic soils. The total amount of organic-C sequestered by the pearl millet was 6.00–9.45 ton C ha−1 per season, while the total CO2 emissions were 1.62–1.82 ton of organic-C ha−1 per season. The application of biochar enhanced the nutrient availability and uptake; moreover, it mitigated the salinity effects in the leaves tissues. Carbon sequestration by pearl millet amended with biochar is an effective strategy to mitigate gas emissions from saline sodic soils.