Evaluation of bamboo as an alternative cropping strategy in the northern central upland of Vietnam: Above-ground carbon fixing capacity, accumulation of soil organic carbon, and socio-economic aspects

The mountains of northern Vietnam have lost significant forest cover during the last decades due to the conversion from natural vegetation to cultivated land, leading to the depletion of soil organic matter and land degradation. The study evaluated bamboo as an alternative cropping strategy in the northern central upland of Vietnam. We analyzed above-ground carbon fixing capacity of bamboo, accumulation of soil organic carbon, and socio-economic aspects as compared to other land use systems. Over the long term, a bamboo-based cropping system compared favorably to several other land use alternatives in the area. Compared to cassava, rice and maize, bamboo provides 49-89% higher average return to labor. Carbon content in bamboo's standing above-ground biomass is 17 tons ha(-1), 18% of that of forest. The soil organic carbon pool under bamboo amounts to 92 tons ha-1 to 70 cm depth, comparable to both forest and regenerated forest and 20% higher than land cultivated with cassava or maize. The study reveals that a shift in land use from annual crops to bamboo provides an annual net gain of soil organic carbon of approximately 0.44 tons ha(-1). Such a shift is constrained however by income insecurity in the early stages of plantation, because bamboo takes 3-4 years to mature and has a low return-per-area basis compared to annual cash crops. The study suggests that a crucial incentive for farmers shifting to bamboo production may be to create alternative off-farm income-generating activities which absorb the labor liberated by the labor extensive farming of bamboo. (C) 2011 Elsevier B.V. All rights reserved.