The Effect of Irrigation and Fertilization Reduction on Yield, Quality, and Resource Use Efficiency of Drip-Fertilized Sugar Beet (<i>Beta vulgaris</i> L.) in Northern China

Sugar beet (<i>Beta vulgaris</i> L.) is a crucial economic crop in northern China. Fertilizer and water waste and environmental contaminations were prevalent during sugar beet cultivation. To enhance sugar beet use efficiency and reduce the amount of water and fertilizer required in cultivation, a three-year experiment was performed. Drip fertilization was employed for irrigation and fertilization. The influence of irrigation reductions (15% and 30%) and fertilization reductions (20% and 10%) on yield, sugar content, and water and fertilizer use efficiency was evaluated. The yield of root and sugar was not significantly impacted by the 10% fertilizer and 15% reduction in irrigation relative to the conventional water and fertilizer supply treatment (CK). The yield was significantly reduced by 20% fertilizer and 30% irrigation reduction. The sugar yield was also reduced by 30% through irrigation reduction treatments. The root sugar content was increased by irrigation and fertilization reduction (except 10% fertilizer reduction treatment). Partial factor productivity (PFP) was significantly increased by fertilization reduction. The irrigation water use efficiency (WUEi) was significantly increased by irrigation reduction. Water use efficiency (WUE) and fertilizer agronomic efficiency (FAE) were increased by a 10% reduction of fertilization treatment relative to CK; the impact on FAE was more significant compared to WUE. The FAE was reduced by an irrigation reduction. The WUE was reduced by 20% through fertilization reduction treatments. The influence of each treatment on PFP, FAE, and WUEi of sugar yield was mirrored in yield, but the range was narrowed. To ensure high production and efficiency while conserving water and fertilizer during sugar beet cultivation within the test area, the optimal irrigation amount was 1041.91 to 1286.27 m³·ha⁻¹and fertilization amount was 394.04 to 408.03 kg·ha⁻¹. This investigation offers irrigation and fertilization parameters for drip fertilization of sugar beet and a theoretical foundation for the crop’s water and fertilizer use.