Among the treatments, WUE was lowest for conventional ridge planting (treatment 7). The second lowest WUE was for the flat gravel–sand mulched field or RFRHS with no-plastic-covered. In general, WUE was relatively high for all RFRHS treatments with plastic-film mulching. The WUE was the highest for the RFRHS with sand mulched furrow plus plastic film whole mulch and the ratio 5:3 of ridge: furrow (treatment 4),