The documented traditional knowledge of West Bengal can be modified to develop viable agriculture technologies with respect to soil, water, crop, nutrient management, and plant protection measures. The essential features of the traditional water harvesting technologies of West Bengal include diversion drains, continuous bunds, contour farming, centralized water courses, stone checks in gullies, and water harvesting in farm ponds. In West Bengal, several ITKs on soil and water management had been practiced such as Bengal’s inundation channel, dongs or jampois, pitcher watering system (kalsi sech padhati), drip watering system, digging pit at agricultural land for water storage and conservation (happa), contour bunding, and roof rainwater harvesting system. Traditional weather forecasting/prediction is in place based on local beliefs and customs. For water management, it is recommended to update local happas. Also, the Gliricidia-based hedgerow agro-forestry systems reduce runoff by 23.3–32.5%, soil loss by 49.5–52.7%, SOC loss by 44.1–47.6%, N loss by 61.5–62.4%, P loss by 54.8–58.1%, and K loss by 53.1–56.3% over the farmers’ practice. For soil fertility management, in situ decomposition and incorporation of grasses and other weeds into the soil along with minimum tillage, green manuring, application of bio char, crop residue management, addition of paddy husk ash, jute leaves, tank silt, compost of water hyacinth, FYM, and vermicompost are recommended. Addition of paddy husk ash fulfill the nutrient requirement of colocasia (145 kg/ha K and only 70 kg N and 16 kg P). Addition of water hyacinth compost and FYM at 10 t/ha can substitute 50% (30 kg) P need of rice crop. FYM at 10 t/ha + crop residues can substitute 50% NPK in rice and therefore cut down 50% cost of chemical fertilizers. Jute leaf fall contributes at least 10–20 kg of N/ha to soil. Tank silt reduces the bulk density of soil and also improves soil organic carbon content. Use of neem leaves, cow dung, tobacco, garlic, silica, lemon leaf dust, and parasi leaves were very effective in controlling insect pests and diseases in various crops. Grain dressing with neem and mustard oil reduces insect pest infestation by 92%. Integration of traditional plant protection measures can reduce the chemical pesticides use to some extent.