LEVELS OF SULFUR EFFECTS ON ALFALFA PRODU CTION AND MINERAL-COMPOSITION

The sulfur (S) effect on alfalfa production and mineral composition wa s studied in plastic pots of five liters of soil Oxisol (Dark-Red Lato sol dystrophic). The experimental design was completely randomized fac torial scheme (4 x 6) with five replications. Four levels of sulfur (0 , 25, 50 and 100 mg dm(-3) of CaSO4.2H(2)O) and one level of K2SO4 (50 mg dm(-3) of S) in six cutting times, were studied. The analyzed vari ables were: dry matter production (DM) and amounts of crude protein (C P), P, K, Ca, Mg and S in the dry matter. The dry matter production an d the P and S levels varied according to the sulfur dosage and the cut ting time. The highest DM levels were observed with the 100 mg dm(-3) of S treatment, and the lowest with the one that did not receive S. Th e last two samples showed the lowest production, probably due to the n utrient extraction. The levels of S raised with sulfur application and diminished in the last cuttings. The opposite was observed with the l evel of P indicating a diluting effect or a negative interaction betwe en P and S. The levels of CP, K, Ca and Mg varied according to the cut ting number.