Potassium cycling by brachiaria decumbens, used as a ground cover plant/Ciclagem de potassio pela braquiaria decumbens, utilizada como planta de cobertura de solo

The objective of this research was to evaluate in the edaphoclimatic environment of Coruripe, the growth rate and accumulation of potassium in brachiaria decumbens, used as a cover crop, in single cultivation. The experimental design was randomized blocks, with five replications, and the plots consisted of five grooves of five meters in length, spaced 0.60 meters apart. The evaluations of the accumulation and partition of dry matter were carried out at 30, 45, 60, 75, 90 and 105 days after the emergence of the plants (D.A.E), sampling in the central lines of the plots areas of 1.0 m2, determining the percentage allocation of dry matter and potassium in leaves and stems + petioles. There was a high rate of dry matter accumulation, ranging from 74.5 to 135 kg of matter per hectare per day. The equation Y (Accumulation of dry matter, in t [ha.sup.-1]) = 0.1561 x was obtained, being x the time in D.A.E. By this equation there is high accumulation of dry matter in the aerial part of the brachiaria decumbens: 14 t [ha.sup.-1] at 90 D.A.E and 16 t [ha.sup.-1] at 105 D.A.E. brachiaria decumbens is a soil cover plant with high productive potential and great potassium recycling.