Synergistic Effects of Biochar and Irrigation on Sugar Beet Growth, Yield, Quality, and Economic Benefit in Arid Regions

Water scarcity hinders sustainable agriculture in arid and semi-arid regions. This study investigated the combined effects of trickle irrigation and biochar application on sugar beet cultivation in northwest China’s arid and semi-arid regions, addressing challenges of water scarcity. Three-year field experiments were conducted using plastic film mulch, four irrigation levels based on crop evapotranspiration (0.6–1.2 ETc), and four biochar application rates (0–30 t ha⁻¹). Results showed that biochar application increased sugar beet germination rates by 7.2–24.5% and enhanced relative chlorophyll content by 3.1–22.1%. Optimal combinations of irrigation and biochar significantly improved growth indices and yield, with maximum values observed under the highest irrigation (1.2 ETc) and 10 t ha⁻¹ biochar treatment. However, the 1.0 ETc irrigation treatment with 10 t ha⁻¹ biochar demonstrated superior water use efficiency (14.8% higher), sustainable yield index (1.1% higher), and economic benefits (1.4% higher) compared to the highest irrigation treatment. Considering growth, yield, quality, water use efficiency, sustainability, and economic factors, an irrigation level of 1.0 ETc combined with a biochar application rate of 10 t ha⁻¹ is recommended for sugar beet cultivation in Xinjiang. This study provides valuable insights and practical strategies for water conservation, high yield, and quality improvement in sugar beet cultivation under arid and semi-arid conditions, contributing to sustainable agricultural practices in water-scarce regions.