Optimization of Irrigation and Nitrogen Levels for a Trade-Off: Yield, Quality, Water Use Efficiency and Environment Effect in a Drip-Fertigated Apple Orchard Based on TOPSIS Method

•Less irrigation amount could improve apple quality and reduce soil nitrate leaching.•Nitrogen over 240 kg ha−1 reduced yield, water use efficiency and fruit quality.•Multi-objective evaluation of water and nitrogen rates was conducted based on TOPSIS.•The upper irrigation limit of 85% FC with 240 kg N ha−1 was optimum for apple orchard.