Effect of Foliar Fertilization with Humic Acid and Garlic Extract on Growth and Yield of Broccoli and its Content of some Secondary Metabolites

Abstract

An experiment was conducted in one of the open fields of the Department of Horticulture and Landscape Engineering, College of Agriculture,Al-Qasim Green University for the autumn season 2021-2022. The experiment included a study of three levels of humic acid (0, 2, 4) ml / liter and three levels of garlic extract (0, 10, 20) ml / liter and the interaction between them in the growth and yield of broccoli plant and its content of total phenols and flavonoids. A factorial experiment (3×3) was conducted according to the split plot design and with three replicates, where each replicate contains 9 treatments. Test the least significant difference L.S.D at the level of 5%. The results showed the humic acid at a concentration of 4 ml / liter in excelled and gave the highest plant height of 57.60 cm, the number of leaves 17.46 leaves / plant, the percentage of dry matter 19.06%, the diameter of curd 23.24 cm, the weight of curd 0.736 kg, and the total amount of phenols in the leaves 1.93 mg / kg. Humic treatment at a concentration of 2 ml / L was significantly excelled in the total amount of phenols in the pink disc at a rate of 1.98 mg / kg. The garlic extract at a concentration of 20 ml/L recorded significantly excelled in recording the highest plant height of 58.42 cm, the percentage of dry matter 19.40%, the curd diameter 23.12 cm, and the curd weight 0.766 kg. In the leaves, it reached 38.15 mg / kg,As for the interaction treatments, most of the interaction treatments recorded significantly excelled in most of the studied traits, but the best interaction treatments were H3G3, which recorded the highest number of leaves 13.60 leaves and the percentage of dry matter 19.73% and the diameter of the pink disc 25 cm and the weight of curd 0.870 kg.While treatment H2G2 recorded the highest value of total phenols in leaves 2.07 mg / kg and treatment H3G2 recorded the highest value of flavonoids in leaves 38.37 mg / kg. Treatment H2G1 recorded the highest value of total phenols in curd amounted to 2.10 mg/kg, and treatment H3G1 recorded the highest value of flavonoids in curd amounting to 38.61 mg/kg.