Seed treatment with cobalt and molybdenum on soybean germination and early growth

Abstract

Cobalt (Co) and molybdenum (Mo) are used in seed treatment to improve seed physiology and initial plant development, but it is necessary to identify the best dose for each cultivar, as these micronutrients in excess are harmful to seeds and plants. Thus, the objective was to evaluate the effect of Co and Mo doses on the physiological quality of seeds and on the initial development of soybean plants. The physiological quality test was carried out on germitest paper rolls and beds of sand, using five doses (0; 0.625; 1.25; 2.5; and 5 ml kg^-1) of a product containing Co at 0.5% and Mo at 6% applied to soybean seeds cultivars SYN1163 and M7739. The initial development of the plants was evaluated in pots in a greenhouse, using the same treatments as the physiological quality test. Increasing doses of Co and Mo increased the number of abnormal seedlings and decreased the germination percentage of both cultivars, with cultivar SYN1163 being the most sensitive to Co and Mo. Increasing doses benefited plant height, SPAD index and number of trefoils in plants. Although the 5 ml kg^-1 dose provided better plant development, this dosage is not recommended, as it impairs seed germination, recommending a dose of 0.625 ml kg^-1 of the product for both cultivars, which corresponds to 0.25 g ha^-1 of Co and 3.0 g ha^-1 of Mo.