Carbon Sequestration Potential of Perennial Horticultural Crops in Indian Tropics

Abstract

Large numbers of horticultural crops are grown in India due to its wide variety of soil and climatic conditions. However, perennial horticultural crops have edge over annuals as they generally need low inputs such as water, energy, etc., and have high productivity values. India has large tracts of waste and marginal lands (96 million hectares of cultivable wasteland). These lands can be brought under perennial horticultural crops for successful and profitable commercial horticulture. Moreover, putting these marginal lands to perennial horticultural crops can enhance carbon sequestration and improve organic carbon content and health of the soils. This also rejuvenates degraded soils, improves the land productivity, enriches the diversity, and protects the environment. Horticultural crops have a great scope for sequestering more carbon in terrestrial ecosystem than agricultural or agroforestry systems. Studies reported that the carbon dioxide sequestration was significantly greater under the perennial crops as compared to annual crops. The carbon sequestration potential of different horticultural cropping systems ranked in the order of mango > cashew > rose > vegetable > medicinal and aromatic plants, and addition of more residues in perennial systems to soil records less emission of CO2 than annual crops. As a consequence, perennial horticulture-based systems provide economic gain through carbon credits. Enhancement of carbon sequestration in perennial systems can be attained by improving soil health and through better carbon management strategies. These include planting high-biomass-producing crops, recycling crop residue, application of manures, switching from annual to perennial crops, adopting crop rotation in place of monoculture, and promotion of agroforestry systems. This chapter mainly describes the role of perennial horticultural systems in enhancing soil carbon, soil organic matter dynamics, carbon fractions, and its assessment in horticultural systems, carbon sequestration potential of perennial horticultural crops, and also the management options available for improving C sequestration under such system.