Suchergebnisse

The objective of this study was to evaluate the forage mass, morphogenetic and structural characteristics, and nutritional value of tropical forage grasses in semiarid conditions. Nine grasses were evaluated, namely, three cultivars of Urochloa brizantha (Marandu, MG4, and Piatã); Urochloa decumbens cv. Basilisk; Urochloa humidicola cv. Llanero; Urochloa ruziziensis cv. Kennedy; and three cultivars of Megathyrsus maximum (Massai, Mombaça, and Tanzania). The experiment was laid out in a randomized complete block design in a split-plot arrangement in which the main factor were the grass cultivars and the secondary factor the seasons, with five replications per treatment. The statistical model included the fixed effect of treatment (grass), whereas the season was included as a random effect within treatments. Urochloa brizantha cvs. Marandu, MG4, and Piatã and Urochloa decumbens cv. Basilisk produced on average 858 kg ha-1 more forage mass than cvs. Kennedy and Basilisk. Megathyrsus maximum cv. Mombaça produced 40% more forage mass than the other cultivars of M. maximum (4205 vs. 3001 kg ha-1). Urochloa ruziziensis cv. Kennedy showed the lowest water use efficiency (36%). Urochloa ruziziensis cv. Kennedy exhibited the lowest leaf weight among the Urochloa cultivars (740 vs. 1319 kg ha-1). There was no treatment effect for leaf weight in the M. maximum cultivars. Urochloa ruziziensis cv. Kennedy showed the highest values of total digestible nutrients and dry matter digestibility (1.84 and 2.34%, respectively) among the other Urochloa cultivars. The M. maximum cultivars showed little differences in nutritional values. Cultivars Marandu, Piatã, and Massai exhibited better productive responses in the edaphoclimatic conditions of this study. However, future studies must be conducted evaluating the adaptation of the forage grass under semiarid conditions. Considering the settings of this study, the grasses Urochloa brizantha cvs. MG4, Marandu, and Piatã, as well as Megathyrsus maximum cvs. Massai and Mombaça, can be used in the semiarid condition.

This study was developed to examine the growth, yield, chemical composition and in situ degradability of elephant grass cv. Napier (Pennisetum purpureum). Five spraying protocols with biostimulants were tested, namely, Control - no application; 1BR - bioregulator at seven days; 2BR - bioregulator at seven days + bioregulator and foliar fertilization at 20 days; 2BR2 - bioregulator at seven days + bioregulator and foliar fertilization at 20 days + ethylene inhibitor at 30 days; and 3BR - bioregulator at seven days + bioregulator and foliar fertilization at 20 days + ethylene inhibitor and bioregulator at 30 days. The grass was cut evenly at a height of 15 cm and harvested at 70 days of regrowth. The experimental area was divided into two blocks according to the slope. Ninety plots were used, totaling an area of 4,608 m2. Each plot was composed of four 4-m rows spaced 80 cm apart. Chemical composition, morphological traits and forage digestibility data were evaluated. The 3BR protocol, with more bioregulator-based applications, resulted in higher canopy (9.78%) and stem (9.58%) compared with control group. The 2BR and 2BR2 treatments provided a 6.5% higher stem than control treatment. The improvement in the nutritional value of Pennisetum purpureum cv. Napier was due to the 17.55% increase in crude protein (CP) content provided by protocol 3BR relative to control group. Treatments 2BR2 and 3BR improved the effective degradability of dry matter (DM). The application of biostimulant protocols increased the potential degradability of neutral detergent fiber (NDF) (+4.1%), with the greatest response seen in treatment 2BR2 in comparison with control treatment. Biostimulant protocols increase the canopy and stem heights and CP content. The application of a bioregulator associated with foliar fertilization and ethylene inhibitor improves the effective degradability of DM and NDF and the potential degradability of NDF in Pennisetum purpureum cv. Napier harvested at 70 days of regrowth.