Hydrogel-assisted deficit irrigation improves sugar beet yield, quality, and water-use efficiency in arid sandy loam soils.

INTRODUCTION

Water scarcity is a major constraint to sugar beet production in sandy soils due to low water-holding capacity and rapid drainage.

METHODS

A two-season field experiment was conducted to evaluate the combined effects of deficit irrigation and hydrogel application on sugar beet yield, juice quality, and water-use efficiency (WUE). Four irrigation regimes were tested: I1 (100% ETc), I2 (85% ETc), I3 (70% ETc), and I4 (55% ETc), in combination with four hydrogel rates: H0 (0), H1 (5), H2 (10), and H3 (15 kg ha-1).

RESULTS AND DISCUSSION: Deficit irrigation significantly increased sucrose concentration and WUE, but reduced root yield from 101.37-103.55 to 80.09-81.73 t ha-1 under sever water deficit (55% Etc).Hydrogel application significantly enhanced root yield (88.12-96.39 t ha-1), sugar yield (12.65-15.52 t ha-1), sucrose content, and WUE while reducing juice impurities. Although the irrigation × hydrogel interaction was not statistically significant (P > 0.05), the combination of moderate deficit irrigation (85% ETc) with 10-15 kg ha-1 hydrogel consistently provided the most favorable balance between productivity, water savings, and economic performance. In contrast, full irrigation combined with 15 kg ha-1 hydrogel achieved the highest net return, whereas moderate deficit irrigation without hydrogel produced the greatest benefit-cost ratio.