Dynamics of biomass and soil carbon sequestration across an age-sequence of Lawsonia inermis plantation in semi-arid Region, Rajasthan, India

Abstract

Lawsonia inermis (henna) is a perennial shrub cultivated as a ratoon crop (annual pruning of hoots) in the hot semi-arid regions of India for its dye-containing leaves. Considering its perennial nature, we hypothesized that henna plantation may sequester carbon in the biomass as well as soil; further, severe shoot pruning may affect the distribution of carbon in the above and below-ground biomass and different soil layers. Therefore, we quantified biomass and soil carbon stock in an age-sequence of 2-, 13, 21- and 56-year old henna plantation to study dynamics and pattern of carbon accumulation. Biomass and soil carbon stock significantly increased with the age of the plantation. While, shoot pruning and plant populations significantly impacted the distribution of carbon in the aboveground and belowground biomass as well as in the soil. Within the plant system, belowground biomass stored more carbon as compared to aboveground biomass. While within the soil, carbon stock was higher in the lower soil layer (15-45cm) as compared to the surface soil layer (0-15 cm). The 2-, 13-, 21- and 56-year old plantation stored about 1.60±0.44, 10.13±1.28, 10.14±1.02 and 11.42±2.50 Mg biomass-C ha-1 respectively with a higher rate of sequestration during early stages of the plantation.