A field and a pot experiment with rush "Seven Islands" (Cyperus malaccensis Lam.) were carried out on a hydromorphic soil at Vale do Ribeira, State of São Paulo, Brazil. Both trials had N, P, K and lime treatments arranged in randomized complete block designs. The highest dry matter yields were obtained for the N-treatments. Potassium was the nutrient absorved in greatest amount by the plants. The highest dry matter yields and the largest stalk diameters were obtained on the N, P and K plus lime treatment. In this treatment, nutrient uptake decreased in the following order: K, N, Ca, S, Mg, P, Mn, Fe, Zn, B and Cu.