EFFECTS OF DIFFERENT EARTHWORM EXTRACT CONCENTRATIONS ON THE GROWTH AND YIELD OF CHINESE CABBAGE (Brassica pekinensis) UNDER FIELD CONDITIONS

 The use of organic fertilizers has been increasingly promoted to enhance crop productivity while reducing the environmental impacts associated with excessive chemical fertilizer use. This study evaluated the effects of different concentrations of earthworm extract on the growth and yield of Chinese cabbage (Brassica pekinensis) under open-field conditions in Vinh Long Province, Vietnam, from July toOctober 2024. The experiment was conducted using a randomized complete block design with six treatments consisting of earthworm extract concentrations of 0, 20, 25, 30, 35, and 40 mL diluted in 20 L of water, with five replications. Earthworm extract was applied as a foliar spray at ten-day intervals throughout the crop cycle. Growth parameters, including plant height, leaf number, canopy width, and stem base diameter, were recorded at different growth stages, while biomass and yield were evaluated at harvest. The results showed that earthworm extract significantly enhanced plant growth and yield compared with the control treatment. The highest concentration (40 mL) produced the greatest plant biomass (290.1 g/plant) and the highest yield (32,757 kg/ha). These findings provide practical evidence for optimizing earthworm extract application to enhance yield and support sustainable Chinese cabbage production under field conditions.