What is the planting cost and income range for colocasia (arbi/taro)?

Take these as ranges. The main establishment costs for colocasia are seed corms (cormels), land preparation, organic manure, fertiliser and labour for planting and earthing up. Seed corm cost can be a meaningful share if you buy fresh material, but you can save your own for the next season. Yields vary widely by variety, soil moisture and crop length, generally a few tonnes per acre with good management on rich moist soil. Income depends on local demand and whether you also sell leaves and petioles. Colocasia is usually a steadier local-market vegetable than an export crop, so returns are tied to nearby mandi demand. Confirm corm cost and current rates with your KVK and local mandi.