Variation in biomass and C stocks in five promising Populus deltoides clones under an agroforestry system

Abstract

Deforestation and faulty land use practices in tropical regions contribute to the largest flux of CO2 to the atmosphere. Therefore, land use systems those sequester large quantities of C are promoted in a big way under CDM and REDD+ programmes. Agroforetry practices undoubtedly have strong potential for C sequestration and sustainable agriculture production. Poplar (Populus deltoides) has been recognised as a potential tree species, encouraged in agroforestry plantations in India. A large amount of variability exists in poplar clones in respect of adoptability, growth and biomass production. In this context, a study has been conducted to see the variation in biomass and C stocks under five promising clones of P. deltoides viz., G3, G48, 65/27, D121 and S7C1 grown under an agrisilviculture system. Monoclonal blocks were planted at 4 x 4 m in a randomised block design with three replications. Total biomass varied from 48.5 to 62.2 Mg ha-1 and C stocks from 24.2 to 31.1 Mg ha-1 in 6-year-old clones. Total C stock in clones was in the order: 65/27 > D121 > G48 > G3 > S7C1. Stem wood accounted 60.4-68.9% to total C storage followed by coarse roots (12.2-18.9%), branches (12.3-15%), leaves (3.02-6.9%) and fine roots (1.5-2.7%). Root-shoot ratio ranged from 0.20 to 0.35. It was the highest in clone G48 and lowest in clone S7C1. The C accretion in poplar clones between 4 to 6 years ranged from 7.38 to 9.43 Mg ha-1 yr-1. The study suggests that the two clones 65/27 and D121 are suitable for biomass production and C sequestration in Chhattisgarh plains.