Effect of potassium fertilization on growth, yield, and some active ingredients of Prunella plant

Background Prunella vulgaris L. is a perennial herb belonging to the Lamiaceae family, it is used as antibacterial, antipyretic, antiseptic, antispasmodic, astringent, carminative, diuretic, febrifuge, hypotensive, stomachic, septic, tonic, vermifuge, and vulnerary properties are all seen to be alternatives to whole plants. Potassium is an important macronutrient for plants because of its ability to affect meristem development, water status, photosynthesis, long-distance assimilation of nutrients, enhancement of some enzyme functions, and regulate ionic equilibrium. Objective To investigate the effects of various potassium fertilizer applications and the quantity of additions on the growth, production, and some chemical constituents of the P. vulgaris plant. Materials and methods Prunella plants were cultivated at SEKEM Company Farm, Belbes, Sharkia, using a drip irrigation system during the two successive seasons of 2018/2019 and 2019/2020 to study the impact of application of different potassium doses (20, 40, and 60 U) and number of added portions (each dose added once or divided into two or three portions) on plant diameter, fresh and dry weight of herb (g/plant and ton/ha), and fresh and dry weight of flowering clusters at both seasons. Photosynthetic pigments in leaves (mg/g fresh leaves), total phenols (mg/g dry herb and flowering clusters), and antioxidant activity (%) in herb and flowering clusters and nitrogen, phosphorus, and potassium concentrations (%) were determined. Results and conclusion Increasing units of potassium fertilization from 20 to 60 U gave the highest plant diameter, fresh and dry weight of herb, and fresh and dry weight of flowering clusters. It also led to an intensification of total phenolics, antioxidant activity %, chlorophyll content, and N, P, and K percentages of all Prunella herbs, whether it was added at two or three portions.