Continuous Digestibility Assessment of Tropical Grasses

The feed value for cattle of three tropical grasses, Gatton (Panicum maximum cv. Gatton), Estrella (Cynodon plectostachyus) and Tifton-85 (Cynodon sp. cv. Tifton-85) was investigated during the growing period, using the method of “continuous digestibility estimation”. Results indicate that feed value is hardly influenced by the growth stage from the 90th day on. Common European in-vitro feed evaluation procedures are not to be recommended for tropical grasses as they presented consistently lower values than did in-vivo measurements

Assessment of Ensilability of Six Tropical Grasses Using Three Different Approaches

The preparation of well-preserved silages is considered increasingly important in the tropics and subtropics. In these regions silage production played a minor role in the past, as ensilability of tropical grasses is generally considered poor. In this study ensilability of six tropical grasses grown in the Paraguayan Chaco Boreal (Panicum maximum cv. Gatton, Cynodon plectostachyus, Cynodon sp. cv. Tifton 85, Digitaria eriantha var. pentzii, Panicum maximum cv. Tanzania and Digitaria milanjiana) was assessed in three different ways: (1) The chemical determination of the ratio between water soluble carbohydrates (WSC) and buffer capacity (BC), (2) the biological rapid fermentation assay using additives of sucrose and/or lactic acid bacteria inoculants, and (3) modelling of silage preparation in plastic bags. BC and contents of WSC were low. Therefore, without additives, acceptable ensilability was attained only with two grasses when previously wilted, while four grasses were poorly ensilable. When soluble carbohydrates and lactic acid bacteria were added, ensilability was enhanced. The rapid fermentation test applied in this study represents an easy to handle tool to asses ensilability of plants with different contents of fermentation substrates (WSC) and to investigate interactions between plants and a variety of epiphytic micro-organisms

Potential Role of Native Bush in the Chaco for Mitigation of Dryland Salinity in Grassland

There is a zone of some 3.000.000 ha with an elevated dryland salinity risk in the Paraguayan Chaco due to a shallow saline ground water table. Evidence is shown of the crucial role native bush seems to play in keeping the water table at a low level and reducing therefore the risk of soil salinisation. In this paper a planned field experiment is outlined to define the tolerable level of deforestation and pasture establishment for a sylvopastoral production system in the Chacoan zone prone to dryland salinity

The physical origins and dominant emission mechanisms of Lyman alpha haloes: Results from the TNG50 simulation in comparison to MUSE observations

Extended Lyman alpha emission is now commonly detected around high-redshift galaxies through stacking and even on individual basis. Despite recent observational advances, the physical origin of these Lyman alpha haloes (LAHs), as well as their relationships to galaxies, quasars, circumgalactic gas, and other environmental factors remains unclear. We present results from our new Lyman alpha full radiative transfer code voroiltis which runs directly on the unstructured Voronoi tessellation of cosmological hydrodynamical simulations. We make use of the TNG50 simulation and simulate LAHs from redshift z = 2 to z = 5, focusing on star-forming galaxies with 8.0 < log10 (M∗ M⊙) < 10.5. While TNG50 does not directly follow ionizing radiation, it includes an on-the-fly treatment for active galactic nuclei (AGNs) and ultraviolet background radiation with self-shielding, which are important processes impacting the cooling and ionization of the gas. Based on this model, we present the predictions for the stacked radial surface brightness profiles of Ly α as a function of galaxy mass and redshift. Comparison with data from the MUSE UDF at z > 3 reveals a promising level of agreement. We measure the correlations of LAH size and central brightness with galaxy properties, finding that at the masses of 8.5 ≤ log10 (M∗/M⊙) ≤ 9.5, physical LAH sizes roughly double from z = 2 to z = 5. Finally, we decompose the profiles into contributions from diffuse emission and scattered photons from star-forming regions. In our simulations, we find rescattered photons from star-forming regions to be the major source in observed LAHs. Unexpectedly, we find that the flattening of LAH profiles at large radii becomes dominated by photons originating from other nearby haloes rather than diffuse emission itself

Brachiaria brizantha cv. BRS Piatã forage yield under integrated crop-livestock-forestry systems in Brazil.

Integrated crop-livestock-forestry (ICLF) systems are increasingly considered for a diversified agricultural production in Brazil. In this study we analysed the forage yield [kg DM ha?1], of Brachiaria brizantha BRS cv. Piat?a for ICLF demonstration plots at the Brazilian Agricultural Research Corporation - EMBRAPA, located in Campo Grande-MS, Brazil. The analysed plots with four replicates corresponded to three production systems: Two integrated crop-livestock-forestry systems (ICLF1 and ICLF2) and an integrated crop-livestock system (ICL). The trees (Eucalyptus urograndis) in the ICLF systems were planted in single rows with 2m between tress and 14 or 22m between rows, resulting in 357 trees ha?1 (ICLF1) and 277 trees ha?1 (ICLF2), respectively. The crop component is soy-bean, planted every 4 years. Grass biomass was sampled monthly in a line of five sampling points at equal distance from each other between tree rows to represent the understory shading gradient. Animal feed intake was considered using the moving cages method. During the dry season (June - October) the forage yields between the different treatments didn?t differ significantly from each other (average 5.4 kg DM ha?1). In the rainy season (November - January) the ICLF system had the highest forage yield (ICLF 17.7 > ICL 6.6 kg DM ha?1). Most likely the main reason for these results is due to the management practice. In the dry season the ICLF systems had such a low stocking rate compared to the ICL system, that in the rainy season the ICLF systems were able to exceed the forage production of the ICL system. In the tree plots during the dry season the forage yields along the shading gradient didn?t differ significantly (average 5.3 kg DM ha?1). In the rainy season the points with higher shading (near the tree rows) had lower forage yields (9.9 and 11.8 kg DM ha?1, respectively) than the central points (16.1 kg DM ha?1). The microclimate within the tree plots has a great effect on the forage production. During the dry season the shading effect of the trees on the whole area is more evenly distributed resulting in similar forage yields along the shading gradient

Respostas fisiológicas e estruturais do capim-piatã sob níveis de sombreamento em sistemas de integração na época seca.

O capim-piatã (Brachiaria brizantha cv. BRS Piatã) destaca-se como uma das principais forrageiras cultivadas em sistemas de integração no Brasil, por seu valor nutritivo e adaptação em consórcio. Sistemas de integração lavoura-pecuária-floresta (ILPF) são apontados como importantes estratégias para sustentabilidade na produção agropecuária, e seu sucesso depende da tolerância da planta forrageira ao sombreamento

Contrasting CO2 and water vapour fluxes in dry forest and pasture sites of central Argentina

The dry forests of South America are a key player of the global carbon cycle and the regional water cycle, but they are being intensively deforested. We used eddy covariance measurements to compare the temporal patterns of CO2 and water vapour fluxes and their relationships with environmental variables in dry forest and pastures sites of central Argentina. Ecosystem fluxes showed clear contrasts in magnitude, timing and response to environmental controls between ecosystems. The dry forest displayed higher daily gross primary productivity (GPP, 10.6 vs. 7.8 g CO2 m−2 d−1) and ecosystem respiration (Reco, 9.1 vs. 7.0 g CO2 m−2 d−1) and lower net ecosystem exchange (NEE, −1.5 vs. −0.7 g CO2 m−2 d−1) than the pasture. These differences were explained by a lower tolerance of the pasture to cool temperatures and drought. The lowest NEE rates were observed between 26°C and 34°C in the pasture, but below this range, NEE increased sharply, switching to a carbon source with temperatures <20°C. By contrast, the dry forest remained as a strong carbon sink down to 18°C. The pasture also showed a stronger drop of GPP with drought compared with the dry forest, becoming a carbon source with soil wetness <25% of soil available water. Rainfall was strongly coupled with GPP in both ecosystems, but the dry forest responded to longer rainfall integration periods. This study helps to understand how ecosystems can respond to climate change, improve global scale modelling and increase the productivity and resilience of rangelands.Fil: Nosetto, Marcelo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Luna Toledo, Emanuel Santiago. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de Chilecito; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Magliano, Patricio Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Figuerola, Patricia Irene. Universidad Nacional de Chilecito; ArgentinaFil: Blanco, Lisandro Javier. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentin

Fortified breakfast cereal consumed daily for 12 wk leads to a significant improvement in micronutrient intake and micronutrient status in adolescent girls: a randomised controlled trial

Background: Poor micronutrient status is reported among adolescents across Europe and USA. This may be related to the well-documented decline in the regular consumption of breakfast by this group. The regular consumption of a breakfast cereal offers a possible means to improve micronutrient status; fortified cereal is likely to have enhanced benefit. A study was conducted to determine the efficacy of the regular consumption of a fortified cereal with milk, compared with unfortified cereal, consumed either as a breakfast or a supper, in improving micronutrient intake and micronutrient status of adolescent girls. Methods: A randomised, double-blind, placebo-controlled intervention trial was conducted in girls recruited at ages 16–19 years, from schools and colleges in Sheffield, UK. Girls were randomised to receive 50 g fortified or unfortified cereal, with 150 ml semi-skimmed milk, daily, for 12 weeks, as a breakfast or as a supper. Dietary intake was estimated using a 4-d food diary and blood collected for the assessment of nutritional status. Within-group changes were tested using a paired sample t test; two-way ANOVA was used to analyse effects of the intervention, with cereal type and time of consumption as factors, correcting for baseline values. The analysis was conducted on 71 girls who completed the study. Results: Consumption of unfortified cereal elicited an increase in the intake of vitamins B1, B2 and B6; consumption of fortified cereal elicited increases in vitamins B1, B2, B6, B12, folate and iron (P < 0.001) and of vitamin D (P = 0.007), all increases were significantly greater than for unfortified cereal. Consumption of the fortified cereal also led to a significant improvement in biomarkers of status for vitamins B2, B12, folate and of iron, compared with girls receiving the unfortified cereal, and maintained vitamin D status, in contrast with the girls receiving the unfortified cereal (P < 0.001). Conclusions: The daily consumption of cereal with milk for 12 weeks by adolescent girls, increased intakes of micronutrients. The consumption of fortified cereal elicited greater increases than for unfortified cereal and improved biomarkers of micronutrient status. The findings justify strategies to encourage the consumption of fortified cereal with milk by adolescents, either as a breakfast or a supper