Ethnopedology and soil properties in bamboo (Bambusa sp.) based agroforestry system in North East India

• Farmers' folk soil knowledge system provides a framework for evaluation of land quality of agroforestry systems
• Farmers' knowledge of kalo mati (black soil) being the most fertile is supported by the laboratory analyses
• Soil nutrient status is positively correlated with the age chronosequences of bamboo plantation
• The SOC sequestration rate declines with increase in age of the bamboo plantation

Bamboo (Bambusa cacharensis) stands are dominant ecosystems in the North East region of India, and have been intricately linked with the livelihood of the rural population for millennia. Therefore, indigenous people have classified soils under bamboos on the basis of their physical appearance for sustainable management of bamboo ecosystems. These traditional systems are still being practiced by the farmers' in the region. This article describes the available information on the system used by indigenous people for bamboo-based agroforestry systems in the Barak Valley, North East India. It also presents analytical data of different soils for their physico-chemical characteristics in relation to soil depth and the clump age. The objective of this study is to integrate farmer-led suitability assessment with that of scientific interpretation of the analytical data. The data presented indicate four basic soil (mati) types: kalo (black soil), lal (red soil), pathal (stony soil) and balu (sandy soil), of which, lal mati soil was the most predominant soil type (40%) in bamboo-based agroforestry system. Increasing clump age was positively correlated with the soil fertility for 0–10 cm, 10–20 cm and 20–30 cm depth, respectively: soil organic carbon (R2 = 0.95*, 0.94*, 0.91*), total N (R2 = 0.95*, 0.88*, 0.69**), available P (R2 = 0.94*, 0.77**, 0.90*) and exchangeable K+ (R2 = 0.91*, 0.79*, 0.61**), suggesting significant impact of bamboo in improving soil fertility through profuse root system and onsite nutrient conservation (*significant at 0.001; **significant at 0.005). The data on scientific analyses are consistent with the traditional soil taxonomy classification used by the farmers. Soil carbon stock (26–35 Mg C ha− 1) and sequestration rate (0.28–0.59 Mg C ha− 1 year− 1) to 30 cm soil depth of bamboo agroforestry suggest its potential role in soil carbon sink management.