Yield of Massai grass pastures in mixed with forage peanut under defoliation frequencies

The persistence of legume plants in mixed pastures is dependent upon its growth habit, and its escape strategy from grazing and defoliation management. The aim of this work is to define the defoliation interval on mixed pastures of Panicum maximum cv. Massai and Arachis pintoi cv. Belomonte. The experiment was conducted in completely randomized blocks with four replications and the seasons of year (SY) considered repeated measures in time. Experimental period occurs from September of 2013 to August of 2014, in an experimental area of 360 m?, divided into 16 plots. Treatments were defoliation intervals (DI) of 14, 28, 42 and 84 days (DI14, DI28, DI42 and DI84, respectively). The tiller density of Massai and stolons of the perennial peanut and the forage mass of both were quantified when the DIs coincided with DI84 (which corresponded to once per season). For the density of tillers and stolons, rectangular frames of 0.5x0.3m and 1.0x0.5m, respectively were used. However, for the forage mass samples a rectangular frame of 0.5x0.3m, at ground level was harvested. After harvesting, samples were separated into grass and legume, weighted and dried to a forced air circulation stove at 65?C for 72 hours. Datasets were submitted to variance analysis using PROC MIXED from SAS program and evaluated by means of regression analysis at 5% of probability. There was interaction between the DI and SY for the tiller density (P = 0.0211) and stolons (P = 0.0091). Linear increase for the tiller density and linear reduction for the stolon density were obtained with increasing DIs in all evaluated seasons. At the total forage mass from grass and legume there was interaction between DI and SY (P = 0.035; 0.0099 and < 0.0001). All SYs showed linear increasing of forage mass and linear decrease from legume mass with increasing DI. Therefore, it follows that cutting or grazing pastures mixed between Massai grass and forage peanut with 14 and 28-day frequency provides greater mass and density of stolons of the legume plant.