Agronomic characteristics and nutritive value of elephant grass clones managed under rotational stocking during the dry period

This study aimed to evaluate the agronomic characteristics and nutritional value of two clones of elephant grass (CNPGL 00-1-3 and BRS Kurumi) operating under rotational stocking in the dry season. A completely randomized design with repeated measures (grazing cycles) and three replicates (paddocks) was used. Clones were managed under rotational stocking with a defoliation interval of 24 days and four days of occupation of paddocks, using Holstein x Gyr heifers with mean body weight of 150 kg. The evaluations were conducted in April/May, May/June, June/July and July/August 2010. Green forage mass was influenced by clone and grazing cycle, with higher mean value observed for CNPGL 03-01-00, which was 17% higher than the value observed for BRS Kurumi, and there was decreased of dry mass of green forage with the advance of grazing cycles. Leaf mass was influenced only by grazing cycle, with gradual reduction from the first to the third cycle. However, in fourth cycle was increase in biomass of leaves, which did not differ from that observed in the second cycle. There was interaction for dry matter production of stem, being observed differences in the first and third cycles for the clones. There was no effect of the factors studied for the production of senescent material. The leaf:stem ratio was influenced by grazing cycles, with interaction of the factors studied. The clone BRS Kurumi kept the leaf:stem ratio stable over the cycles, while clone CNPGL 1-3-00 presented a decrease in leaf:stem ratio from first until to third cycle. The content of crude protein (PB) was not influenced by the factors studied, with average values of 15.3% and 15.8% PB for the CNPGL 00-1-3 and BRS Kurumi clones. Neutral detergent fiber (NDF) and the in vitro dry matter digestibility (IVDMD) were affected only by grazing cycles. The highest values of NDF were observed in the three first grazing cycles, with values of 55.5%, 56.0% and 55.7% from the first to the third grazing cycle, respectively, while in the fourth cycle was obtained the value of 50.5%. There was a decrease in the IVDMD until the third cycle. In the fourth cycle the IVDMD values were similar to the first cycle. The clones did not differ in relation to biomass production, morphological composition and nutritional value, during the dry season

Agricultural answers and chemical composition of Massai grass under different nitrogen doses and urea sources

Under the hypothesis that modifying nitrogen sources and doses could increase nitrogen fertilization efficiency and productivity and improve forage quality, this study aimed to evaluate the morphological composition, structural characteristics and chemical composition of Panicum maximum cv. Massai forage cultivated under different urea sources (common and coated with Policote®) and nitrogen doses (200, 400 and 600 kg ha-1 year-1) during the autumn, winter and spring of 2014 and the summer and autumn of 2015. The experiment was carried out in Seropédica, RJ, under a randomized complete block design in a factorial arrangement (3x2) + 1 with four replications. High nitrogen rates promoted higher percentages of leaf blade dry mass and lower percentages of dead material dry mass in the forage mass and provided higher tiller population density and forage accumulation rate of Massai grass during the studied seasons. The use of coated urea promoted higher levels of crude protein in the forage than did the use of common urea in all seasons. The intensification of nitrogen fertilization reduced the nitrogen use efficiency but benefitted the structural characteristics, forage accumulation and chemical composition of Massai grass forage. The use of coated urea promoted greater of nitrogen use efficiency during all seasons of the year