Integrated Effects of Soil Sulfur and Foliar Calcium, Boron, and Sorbitol Application on Growth, Yield, and Quality of Broccoli

Abstract

With the aim of manipulating metabolism for increasing yield and bioactive compounds in broccoli, this investigation was carried out during the two winter seasons of 2021/2022 and 2022/2023 at Shabrawish Village, Aga, Dakahila Governorate to study the effect of sulfur addition to the soil in combination with foliar spraying with calcium, boron and sorbitol, either singly or in combination, on growth, yield and bioactive compounds attributes of broccoli. The experiment was laid out as a split-plot design in a randomized complete block with three replicates. Sulfur (S) was added at the rate of 100 kg/ fed in main plots whereas sub-plots were assigned to foliar spraying treatments comprising, chelated calcium (Ca) at 0.5 %, boron (B) at 100 ppm, and sorbitol (SOB) at 0.5%, as well as their combinations. Results revealed that S soil addition, foliar spraying with Ca, B, or SOB, or their combinations increased growth attributes; head’s weight, dimensions and dry matter; total head yield estimated aston / fed. as well as contents of N, P, K, Ca and B in both the leaf and head; chlorophyll a, b, as well as total chlorophylls; total carotenoids; ascorbic acid (AsA); total soluble solids (TSS) and total carbohydrates throughout the experimental period. The effect of the interaction between soil S addition and foliar spraying treatments was positive and significant on all tested attributes, with the combination between S, Ca, B, and SOB was the most effective in increasing these attributes. Moreover, without S addition, foliar spraying treatments increased all tested parameters, though with a lower magnitude, and the combination treatment (Ca+B+SOB) was the most effective in this respect. Based on obtained results, it could be concluded that yield of broccoli could be increased quantitatively and qualitatively by either soil addition of S at 100 kg/ fed. or its combination with either individual or synergistic actions of foliar fertilization with 0.5% Ca, 100 ppm B, 0.5% SOB, and preferably by combining all the tested materials.