Productivity and Quality Variations in Sugar Beet Induced by Soil Application of K-Humate and Foliar Application of Biostimulants Under Salinity Condition

Abiotic stresses are the most major limitation to crop production, causing yield losses up to 50%, and consider the major challenges for production of crops. Thus, an experiment was conducted to determine how sugar beet would respond to soil application of K-humate rates and foliar application of biostimulants under salt stress. Split-plot design in three replicates was used in both seasons, where K-humate rates fertigation (control, 12, and 24 kg ha−1) allocated in the main plots, and different foliar application of BS arranged within the subplot (i.e., (1) water spray, (2) salicylic acid (SA) at the rate of 100 mg L−1, (3) fulvic acid (FA) at the rate of 1.2 kg ha−1, (4) hydroxyproline (HP) 1000 mg L−1, (5) SA at 100 mg L−1 + FA at 1.2 kg ha−1, (6) SA at 100 mg/L + HP at 1000 mg L−1, (7) FA at 1.2 kg ha−1 + HP at 1000 mg L−1, (8) SA 100 mg L−1 + FA 1.2 kg ha−1 + HP 1000 mg L−1) in the two seasons. The finding results revealed that soil application of K-humate, foliar application of BS, and their interaction significantly affected yield, growth, and quality characteristics of sugar beet under soil salinity, furthermore with soil application of K-humate at the rate of 24 kg ha−1 with foliar spray of FA + HP recorded the highest of growth traits, top, root, sucrose %, sugar yields/ha−1 and the lowest values of Na content in the juice and quality of sugar beet under the study conditions, Alexandria, Egypt.