Effect of tillage and crop establishment, residue management and K fertilization on yield, K use efficiency and apparent K balance under rice-maize system in north-western India

•In rice-maize system, application of residues and K increased yields and soil K supply.•K use efficiency in both rice and maize was invariably greater under residue removal plots.•Responses to K fertilizer were greater with residue removal than residue retention.•Apparent K balance with residue removal were highly negative even with K fertilization.•Zero-till system helped retention of K in top soil layer.