Recovery of Pasture Degraded Urochloa Decumbens By Introducing Stylosanthes Spp.

In Brazil, more than half of the pasture areas are degraded; the introduction of leguminous can be a viable way to recover them. This study aims to evaluate different ways of introducing Stylosanthes in a degraded pasture of U. decumbens, in Andradina, São Paulo, Brazil. An experimental design in randomized blocks with four replications was used, in a 7x2x2 factorial scheme, being 7 treatments [control treatment B. decumbens (B), desiccation partial (E); total desiccation (D); tillage (T); scarification (S); harrowing rome (H); plowing+disking (C)]; split plots (with or without phosphate fertilizer); 2 years evaluation (2012 and 2013).  The treatments affected the dry matter production (DMP), which ranged from 10.7 (T) to 17.1 t ha^-1 (H) in 2012 and from 7.7 (C) to 11.7 t ha^-1 (T) in 2013. This drop in productivity can be explained by low rainfall in 2013. In the total DMP of two years, E, H, C and D treatments were superior to B, with no significant difference between the others. There was positive influence of P fertilization on the average DMP in 2012 (13.6 to 15.5 t ha^-1); in 2013 there was no influence of fertilization, possibly due to drought. For soil chemical properties, there was no significant interaction between the variables, however there was isolated effect of phosphorous fertilization and of the years evaluated. There was an increase in organic matter, K, Mg, Cu, Mn, pH and CEC, in 2013. Analyzing P fertilization, there was a positive response to Ca and CEC. There was positive interaction for P content in soil, which increased with time and with P fertilization. In conclusion, all methods of leguminous introduction responded positively to pasture production; there was a positive response of P fertilization on favorable weather conditions.