The Impact of Incorporating Humic Acid and Poultry Manure Fertilizer on the Growth and Yield of Kale Plants

The research aimed to investigate the effects of humic acid and poultry manure on the growth and yield of kale plants throughout the growing season. Two concentrations of humic acid (4 and 6 g L^-1) and two levels of poultry manure (100 and 200 g m^-2), in addition to the control, were used. The findings revealed notable variations in the vegetative, quantitative, and qualitative traits of kale plants in response to humic acid. The incorporation of 6 g L^-1 humic acid markedly enhanced all vegetative and quantitative traits, including leaf weight, leaf count, average yield per plant, and total yield, which were recorded at 8.55 g, 30.87 leaves per plant, 265.9 g per plant, and 10.63 tons ha^-1, respectively. The application of poultry manure at a rate of 200 g m² significantly influenced all vegetative and quantitative traits, including leaf weight, leaf count, average yield per plant, and total yield, except leaf chlorophyll content, which measured 9.55 g, 30.90 leaves per plant, 299.3 g per plant^-1, and 11.93 tons per hectare, respectively. The interaction outcomes revealed substantial disparities in the examined characteristics. The two-way interaction treatment (6 g L^-1 humic acid and 200 g m² poultry manure) significantly enhanced the majority of vegetative, quantitative, and qualitative attributes of kale, including leaf weight, leaf count, average yield per plant, total yield, and percentages of NPK, protein, and vitamin C, in contrast to the control treatment, which exhibited the lowest values, as well as the other treatments..