The Efficiency of The Mineral K-Fertilization Combined with Soaking/Spraying by Chitosan Solution to Enhance the Sugar Beet Productivity under Sandy Soil Conditions

Expanding the sugar beet (Beta vulgaris L.) production in sandy soils, as reclaimed soils, is highly recommended. This study aims to evaluate the single and combined effects of soaking and/or spraying with chitosan solution, with the application of mineral K-fertilization on the availability, uptake of the N-P-K nutrients, and the yield of sugar beet cultivated in sandy soil. Two field experiments were carried out in a split-plot design with three replicates. The main factor (F1) was the mineral potassium (K) fertilization applied at the rates of 50%, 75%, and 100% of the recommended dose (RD). The sub-factor (F2) was the chitosan soak and/or spray treatments. The results indicated that increasing the applied K2O rate from 50% to 100% RD has increased the range of the soil available (mg kg-1) N-P-K by 54.5-106.7%, 60.6-140.1%, and 15.5-101.9%, respectively, relative to the initial soil before the experiment. The sugar beet yield (Mg ha-1) was increased significantly by 18.1% at a significance level p ≤ 0.05. The combined application of 75% K2O with soaking seeds has increased the nutrient availability by 26.2% (N), 41.6% (P), and 62.5% (K), relative to the zero-chitosan treatment. The 75% K-fertilization rate combined with repeated spray by the chitosan solution can be recommended to improve the sugar beet yield and quality.Chitosan can be included in the fertilization programs by soaking/sprayingthe fertilizer solutionunder sandy soil conditions.