Conservation agriculture based sustainable intensification: Increasing yields and water productivity for smallholders of the Eastern Gangetic Plains

•CASI management options were evaluated for two years in five rice-based cropping systems across the EGP.•The yield and water productivity of crops and cropping systems was quantified in 433 participatory on-farm trials.•CASI practices increase the yields of both maize and wheat crops by an average of 5%, and improve the water productivity of rice-maize and rice-wheat systems by an average of 9%.•Partial CASI options provide lesser, but valuable, benefits to yields and water productivity in rice-based cropping systems.