This work was carried out to evaluate biomass allocation in Brachiaria subquadripara plants at different concentrations of N, P and K in nutritional solution. The experiment was arranged in a completely randomized design with six replications and treatments were 5 levels of N, P and K (0, 25, 50, 75 and 100% of the base solution concentration) for 5 times (intervals of 7 days). The base solution used refers to the dilution of 20% of the nutritional solution used for crops. The absence of N provided greater allocation of biomass in roots than on stems until the fourth week (28 DAT). The addition of 25 and 75% phosphorus in the solution provided biomass increments of 6.6 and 5.8%, respectively, in relation to the absence of phosphorus. Under potassium deficiency conditions, the plants tended to maintain a constant proportion of stems and roots, but leaf production decreased with plant age.
aquatic weed; nutrient; weed