Morphophysiology of forage peanut submitted to different intensities of defoliation on grazing with sheep

The aim was to monitor the growth, the dry mass accumulation curve, and the structural photosynthetic components of forage peanut pasture, in different intensities of defoliation in sheep rotational stocking. Experimental area of Arachis pintoi (cv. Amarillo) had 0.29 ha divided equally into 16 paddocks of 180 m2 where they were assigned in a randomized block design with four repetitions; intensities of grazing were very lenient, lenient, moderate, and severe, represented by the residue heights of 11.2, 8.4, 5.9, and 3.2 cm respectively, from 14 cm (pre-grazing height). Weekly evaluations were carried out in the remaining period and in the pre and post-grazing period, with the forage cut to soil level for the determination of the dry mass available, separation of the structural components of pasture, and determination of the area of the leaflets. From this information, the values of leaf area index, leaf to stem ratio, and growth ratios were calculated. With these results, for the growth variables, regression curves were estimated as a function of the rest days offered by each treatment. Despite the lower mass of forage obtained when the leaf area is severely defoliated, the species presents even accumulation of biomass and foliar area. Severe grazing intensity resulted in greater accumulation of leaves, reflected in the leaf area ratio and leaf weight ratio. The lenient intensities provide less rest time between grazing, requiring a greater number of paddocks. Under the research conditions, severe defoliation provides less forage to the animals.