Stimulating the growth, storage root yield and quality of carrot plants by phosphoric acid, potassium and boric acid foliar applications

Abstract

Two field experiments were conducted on November, 2017/2018 and 2018/2019 at the Faculty of Agriculture, Ain Shams University Farm, Shoubra El-Kheima, Egypt. Foliar applications of phosphoric acid (as P source at 1000 and 2000 ppm), potassium (KOH as K source at 1000 and 2000 ppm), boric acid (as B source at 500 ppm) and their combinations were designed in complete randomized block design with three replications and sprayed at 30, 55 and 75 days after sowing to enhance the growth, yield and the biochemical constituents of carrot (Daucus carota L.) cv Kuroda orange. Data indicated that spraying phosphoric acid, potassium, boric acid individually and in combination stimulated vegetative growth characters, biochemical constituents and storage roots yield compared to control plants in both seasons. Foliar supply of the individual phosphoric acid (2000 ppm) and the combined treatment of P (2000 ppm) plus K (2000 ppm) and B (500 ppm) achieved higher significant improvements of most vegetative growth traits, macro and micronutrients, photosynthetic pigments in carrot leaf at 90 days after sowing and storage roots yield, N, P, K, Mg, Ca, Fe, Mn, Zn, Cu, carotene, vitamin C, total sugars concentrations and TSS in storage roots at 105 days after sowing compared to control plants.