BackgroundOptimizing biochar application is vital for enhancing crop production and ensuring sustainable agricultural production. A 3‐year field experiment was established to explore the effects of varying biochar application rates (BAR) on crop growth, quality, productivity, and yields. The BAR were set at 0, 10, 50, and 100 t ha–1 in 2018, 0, 10, 25, 50, and 100 t ha–1 in 2019, and 0, 10, 25, and 30 t ha–1 in 2020. Crop quality and growth status and production were evaluated using DTOPSIS‐EW, PCA, MFA, GRA, and fuzzy Borda combination evaluation method.Results(1) Low‐dose BAR (≤25 t ha–1 for cotton; ≤50 t ha–1 for sugar beet) effectively increased biomass, plant height, leaf area index (LAI), water and fertility (N, P, and K) productivities, and yield. Biochar application increased the salt absorption and sugar content in sugar beet, with the most notable increases being 116.45% and 20.35%, respectively. Conversely, BAR had no significant effect on cotton fiber quality; (2) GRA method was the most appropriate for assessing crop growth and quality; (3) The most indicative parameters for reflecting cotton and sugarbeet growth and quality status were biomass and LAI. (4) The 10 t ha–1 BAR consistently produced the highest scores and was the most economically viable option, as evaluated by DTOPSIS‐EW.ConclusionThe optimal biochar application strategy for improving cotton and sugar beet cultivation in Xinjiang, China, is 10 t ha–1 biochar applied continuously.This article is protected by copyright. All rights reserved.