Suchergebnisse

The objective of this study was to evaluate the ability of savanna thinning and enrichment with grasses to maintain local biodiversity and intensify biomass production in an area of Caatinga. The study was carried out in a Caatinga area thinned into savanna and an unmanipulated area during the rainy and rainy-dry transition seasons of 2016. The herbaceous biomass production, diversity, and equability of the thinned and unmanipulated areas were evaluated by calculating values of the Shannon-Weaver (H?) and Pielou (J?) indices. The establishment of massai and buffel grasses in the savanna-thinned area was also evaluated. The area thinned into savanna produced more native herbaceous forage biomass in both the rainy (1,940.55 kg ha-1) and rainy-dry transition seasons (1,918.55 kg ha-1) than that in the unmanipulated area in the same periods (78.42 and 37.40 kg ha-1, respectively), without compromising biodiversity, as the Shannon-Weaver and Pielou indices for the savanna-thinned area (H? = 1.48 and J? = 0.62, respectively) and for the unmanipulated area (H? = 1.29 and J? = 0.72) were comparable. The frequency of species with a known forage value in the area thinned into savanna was still able to increase by 141% in the rainy season and 1,700% in the rainy-dry transition season. Massai grass became better-established in the savanna-thinned area that buffel grass, where it produced up to 3 t of dry matter ha-1. The thinning and enrichment treatments promoted an increase in the biodiversity of the area, and moreover contributed to increases in forage biomass in the Caatinga.

This study aimed to analyze fragments of rangelands through spectral responses and land cover change by livestock in regions of the Caatinga biome through remote sensing. For spectral behavior, the surface reflectance bidirectional (SRB) and spectral indexes of vegetation were used to verify the ragelands seasonality. Land cover change detection of Ouricuri and Tauá through Landsat-8 images with a 16-day revisit interval, were processed in the Google Earth Engine platform (GEE) and software Quantum GIS version 2.18 (QGIS). In the GEE platform, annual mosaics and stacking of the spectral bands were generated for the classification of images, and in sequence the production of thematic maps in QGIS. The analysis of land cover change considered the classes: thinned Caatinga, conserved Caatinga, herbaceous vegetation, bare soil, water and others. The analysis of the spectral responses showed that the vegetation monitored in Ouricuri presented higher SRB in the infrared band and lower SRB in the red and blue bands, and that caused the pasture to produce higher vegetation indexes than the other locations. Through validation, it was observed that in Tauá, there was an overall accuracy of 91% and Kappa index of 89%, and in Ouricuri there was an overall accuracy of 90% and Kappa index of 86%, indicating excellent correctness of the classification model. The classification model proved to be effective in verifying the temporal and spatial land cover change, making it possible to identify places with the vegetation that was most affected and susceptible to degradation and generation of political support to minimize damage to the Caatinga Biome.

The objective of this study was to evaluate the influence of replacing soybean meal (SM) with castor bean cake (DCC), detoxified using two alkaline products, on the feeding behavior and physiological parameters of Saanen and Anglo-Nubian goat breeds with an initial body weight of 16.22 ± 0.67 kg. The treatments consisted of three diets that were isoproteic and isoenergetic: the first with a standard formulation based on corn and SM, the second with DCC detoxified using calcium hydroxide (Ca(OH)2 DCC), and the third with DCC detoxified using sodium hydroxide (NaOH DCC). A completely randomized design with a 3 × 2 (diets and breeds) factorial arrangement and four replicates per combination was used. A dietary effect on the intake of dry matter (DM) and NDFap (P = 0.02 and 0.01) was observed, with lower values for goats fed NaOH DCC than the other diets. The diets influenced feeding and rumination times (P = 0.04 and 0.03). An interaction (P = 0.04 and 0.01) between the breeds and the SM-based diet was found for time variables (other activity and idle time). Increased feeding and neutral detergent fiber (NDF) rumination efficiencies were observed for goats fed SM and Ca(OH)2 DCC (P = 0.03 and 0.01). Goats fed the NaOH DCC diet consumed large amounts of water, while Saanen goats urinated more times than did Anglo-Nubian goats. The diets had an effect on the heart rate and rectal temperature (P = 0.01 and 0.02), while the body surface temperature was influenced by the breed. Thus, Ca(OH)2 or NaOH DCC has a great potential to replace SM in the feeding of dairy goats. When used as diet for goats in the growth phase, NaOH DCC causes a reduction of DM and NDF intakes. Neither DCC negatively affected the physiological parameters of goats.

This study aimed to evaluate the morphophysiological characteristics of irrigated Pennisetum purpureum cv. Cameroon subjected to doses of an organic compost from waste generated by production and slaughter of small ruminants. The experiment was carried out in a grassland, during four growth cycles of 60 days. The area is located in the Embrapa Caprinos e Ovinos unit, in Sobral - CE, Brazil. Treatments consisted of organic compost doses (0, 13.3, 26.6, 39.9, 53.2 and 79.8 Mg ha-1) plus a mineral fertilization (nitrogen and potassium) at doses equivalent to 720 and 900 kg ha-1 year-1, respectively. The experimental design was arranged in completely randomized blocks, totaling four blocks with seven treatments each, in a split plot scheme with repeated readings over time. The plots corresponded to seven doses of an organic compost and an additional treatment (mineral fertilizer), and subplots to four growth cycles. The variables analyzed were total herbage biomass (THB), canopy height (CH), tiller population density (TPD) and water use efficiency for green leaf biomass production (WUEGLB) and green stem biomass (WUEGSB). In the first cycle, TPD decreased linearly with increasing doses of the compost, with 47 tillers m2 at the dose of 79.8 Mg ha-1, while THB and WUEGLB variables behaved quadratically, with a maximum point of 23.53 Mg DM ha-1 cycle-1, and 16.33 kg DM mm-1 for the doses of 66.52 and 62.94 Mg ha-1 of the organic compost. We concluded plant structural characteristics and water use efficiency were responsive to applications of the organic compost, and we recommend the dose of 67.7 Mg ha-1.

The objective of this study was to assess the agronomic and nutritional responses of the elephant grass cultivar Carajas when subjected to fertilization with protected and conventional urea. A randomized block design with 4×2+1 factorial arrangement was adopted. The treatments consisted of four doses (100, 200, 400, and 800 kg N ha-1), two nitrogen sources (conventional and protected urea), and one additional treatment without fertilization. The experiment was carried out from October 2015 to March 2016, in a semi-arid region with a dystrophic yellow latosol type soil. The application of conventional urea was done with each of the multiple cuts performed per year, whereas the protected urea was applied in a single dose. Total senescence rate (TSR), leaf and stem elongation, height, tiller density, total forage biomass, green leaf and stem biomass, and dry matter all increased with increasing N doses. However, the phyllochron, live material/dead material ratio, and agronomic efficiency all decreased with N increasing dose. Plants fertilized with protected urea presented greater TSR and phyllochron. Mineral matter content was higher in plants fertilized with conventional urea. Neutral detergent fiber content was maximized at a dose of 437.63 kg N ha-1. The protected urea resulted in a higher value of leaf/stem ratio at the 400 kg N ha-1 dose, whereas ether extract and crude protein at the 800 kg N ha-1. With application of conventional urea, the highest crude protein value occurred at a dose of 100 kg N ha-1. The morphogenesis, structure, production, and chemical composition of elephant grass 'Carajas' were all positively influenced when nitrogen doses were increased, with the recommended optimal dose for use being 400 kg N ha-1 for both sources. The use of protected urea is recommended because of its slow release and need for only a single application.

This study aimed to evaluate the agronomic characteristics and nutritional value of Massai grass (Megathyrsus maximus 'Massai') pastures fertilized with different nitrogen levels and subjected to deferred grazing. A completely randomized experimental design (CRD) was adopted, with including five nitrogen levels (zero, 100, 200, 300, and 400 kg ha?1), and five replications (plots). The degradability trial used a CRD including a 6 × 5 factorial arrangement, consisting of six rumen-incubation times (6, 24, 48, 60, 84, and 96 h) and five levels of nitrogen in different plots. One fistulated sheep, with a live weight of 60 kg, was used in the experiment. Total herbage biomass, dead herbage biomass, and height showed a quadratic response to nitrogen fertilization levels of 100 to 200 kg ha-1 resulted in greater tillering. Protein and dry matter content increased linearly with nitrogen fertilization level, leading to increase in fibrous components. The increase in NDF and ADF contents might be a consequence of the reduction in NCE, and the high flowering rate of the grass, owing likely to the reduction in metabolism of the grass in an attempt to extend its lifetime. Nitrogen levels of 300 kg ha?1 or higher affected the productive characteristics positively, whereas the chemical characteristics were negatively affected.

This study aimed to evaluate the production performance, quantitative carcass characteristics, and economic viability of lambs of genetic group Pantaneiro finished under four production systems: 1) Stockpiled Brachiaria brizantha cv piatã pasture; 2) Consortium of sorghum intercropped with Brachiaria brizantha cv piatã; 3) Feedlot based on sorghum silage and 2% body weight energy-protein supplementation, 4) Feedlot based on sorghum silage and 4% body weight energy-protein supplementation. Were used one hundred Pantaneiro lambs with an average body weight of 17.85 ± 2.50 kg and at 70 ± 15 days of age, approximately. The average final body weight and total body weight gain of the animals finished on the consortium of sorghum intercropped with Brachiaria brizantha cv piatã were higher than those obtained with feedlot based on sorghum silage and 2% body weight energy-protein supplementation. However, when this system were compared with sorghum silage and 4% body weight energy-protein supplementation, these characteristics did not differ (P > 0.05). Hot and cold carcass weights were lower when animals were fed sorghum silage and 2% body weight energy-protein supplementation as compared with the animals finished on the other systems. The greatest hot (48.20%) and cold (45.83%) carcass yields were observed in animals finished on sorghum silage and 4% body weight energy-protein supplementation. For the carcass compactness index, animals that received sorghum silage and 4% body weight energy-protein supplementation obtained higher values than those observed for 2% of supplementation. The economic evaluation showed a great return for the finishing systems, except for sorghum silage and 4% body weight energy-protein supplementation, and concluded that finishing lambs in a crop-livestock integration system presented a higher benefit/cost ratio (1.61). Therefore, based on the conditions under which this study was conducted, the crop-livestock integration is the most viable system for finishing lambs.

This study aimed to evaluate the physiological parameters and the biomass flow and structural characteristics of BRS Massai and BRS Tamani grasses under different irrigation conditions. The rating of gas exchange, biomass flow and structural characteristics were performed in dry periods and dry/rainy season, under the water supply of 30; 60; 90 and 120% of the reference evapotranspiration (ETo). The experimental design was completely randomized in a factorial arrangement 4x2 (water supply and grass). The experiment was conducted in pots with capacity for 7.5 dm³, using as substrate layer of 0-0.2 m soil. There was no effect (P < 0.05) between the gas exchange in the dry period, having the largest growing parameters of irrigation schemes. In the transition period of dry/rainy, we observed a reversal behavior in relation to the dry period, showing a rapid recovery of grasses under the minor water supply. It was observed quadratic behavior to concentrations of CO2 in the leaf mesophilic (Ci) with maximum point to the BRS Massai grass and minimum point to the BRS Tamani grass, where the major and minor Ci were 119 and 48 ppm in the water supply of 107 and 35% of ETo, respectively. In relation to the biomass flow, the BRS Tamani grass presented greater stem elongation rate and leaf senescence rate in relation to BRS Massai in both periods assessed. In the dry period, we observed a higher biomass production of green leaf blades in the BRS Tamani grass, while in the transition dry/rainy season, the results for this variable were similar, and at the same time that observed higher accumulation of green culm biomass to the BRS Tamani grass, which certainly affected its structure. It is concluded that the application of a minimum daily water supply of 30% of ETo allows the maintenance of BRS Massai and BRS Tamani grasses without incurring the death of tillers and reduction of regrowth vigor, whereas the water supply of 90% of ETo favors the morphophysiological characteristics, especially of BRS Tamani grass.