University Romulo Gallegos
University Romulo Gallegos
Organic matter composition, pH, cation exchange and texture, on five soils located between 670 and 1600 meters above sea level in the basin of river Maracay, Venezuela [Composição da materia orgânica, pH, troca catiônica e textura de cinco solos localizado entre 670 e 1600 metros acima do nível do mar na bacia do rio Maracay, Venezuela] [Composición de la materia orgánica, pH, intercambio catiónico y textura de cinco suelos ubicados entre 670 y 1600 msnm en la cuenca del río Maracay, Venezuela]
Ruiz Dager M.,University Romulo Gallegos |
Elizalde G.,Central University of Venezuela |
Rios Cabrera M.M.,Libertador Experimental Pedagogical University
Revista de la Facultad de Agronomia | Year: 2017
The variability of some soil attributes was studied according to their depth in a pedogeomorphological sequence of the Maracay river basin, Venezuela. The study was part of an overall project, oriented towards the diagnosis of the factors that had an impact on this soil degradation and the role of organic matter in these changes. Samples were taken from the genetic horizons of five soils located between 670 and 1600 meters above sea level. Total organic carbon (TOC), carbon associated with humin, humic acids and fulvic acids and non-humic carbon were determined, as well as pH, interchangeable Ca and Al, cation exchange capacity, exchangeable bases and texture. TOC reached 5.1% in the highest altitude site, while the values did not exceed to 1.48% in the foothills, showing a tendency to increase with altitude. The texture was uniform, especially the content of clay and sand, giving a textural class sandy loam, except at the point of highest altitude where the textural class was loam. The values of pH ranged between 3.39 and 5.37 with a tendency to increase with reducing elevation. In conclusion, the contents of organic matter were related to the altitudinal tier, parent material, slope, vegetation, texture and pH. Most of the organic carbon was associated with the humins, indicating that a high proportion of organic matter was not easy to biodegrade and was forming chelates with the mineral fraction. 2017, Universidad del Zulia. All Rights Reserved.
Schargel W.E.,University of Texas at Arlington |
Rivas G.A.,University of Zulia |
Makowsky R.,University of Alabama at Birmingham |
Senaris J.C.,Museo de Historia Natural la Salle |
And 4 more authors.
Systematics and Biodiversity | Year: 2010
The phylogenetic relationships and species boundaries of the diurnal geckos of the genus Gonatodes in the Guayana region are examined. Seven species of Gonatodes are recognized for the region, six of which are endemic to this region and form a monophyletic group together with G. hasemani from the southern part of the Amazon Basin. Two of the six species in this group are new to science, one of which is endemic to Venezuela and it is described here. Taxonomic accounts are provided for all the Venezuelan species of Gonatodes that are endemic to the Guayana region. The phylogenetic relationships of Gonatodes suggest that the diversity of this genus in the Guayana region has resulted mostly from in situ diversification rather than multiple colonization events by different lineages. The phylogenetic analyses also support that G. antillensis, the only nocturnal species in the genus, is indeed nested within Gonatodes, indicating re-evolution of some traits associated with nocturnal life. Finally, we comment on a recently proposed framework of temporal diversification in Gonatodes and suggest that we are still a long way from attaining a complete understanding about the systematics of this genus. © 2010 The Natural History Museum.
Effect of rice grain (Oryza sativa L.) particle size and non protein nitrogen source on in vitro ruminal digestibility of Cynodon dactylon [Efecto del tamaño de partícula del grano de arroz (oryza sativa l.) y la fuente de nitrógeno no proteico sobre la degradación ruminal in vitro de cynodon dactylon]
Olivo A.,Central University of Venezuela |
Ojeda A.,Central University of Venezuela |
Landinez J.,University Centroccidental Lisandro Alvarado |
Pizzani P.,University Romulo Gallegos
Livestock Research for Rural Development | Year: 2013
The objective was to evaluate the effect particle size of supplement and two non proteic nitrogen (NPN) sources on in vitro gas production and apparent degradation of Cynodon dactylon (6.3% PC, 36.6% FC, 0.37% Ca and 0.79% P). A complete randomized design with a 3×2 factorial arrangement, three particles size (PS: 0.5, 1 and 2 mm Ø) of rice grain and two NPN sources with different rate of release: urea and protected urea, was used. Protected urea was a commercial product consisting of granulated urea covered with a slowly biodegradable polymers film. The rice grain was equivalent to 20% fibrous resource, including urea or protected urea in respect to 8.7 g NPN/kg diet. Gas production at 3, 6, 9, 12 and 24 h, and apparent degradation of dry and organic matter at 24 h were measured. Independently of the NPN source used, and after 12 h of fermentation, 0.5 mm PS increased (P= 0.03) the gas production in 32.7%, and the dry and organic matter degradation (P<0.01) in 14.5 and 14.1%, respectively. No effects (P>0.05) were observed of the others evaluated factors in the rest of the fermentation period. The present study showed that protected urea didn't have effects on the parameters of in vitro ruminal fermentation, and the supplement particle size could be considered a tool to increase the fibrous resources used by ruminants.
Herrera A.M.,National Experimental University of Táchira |
Martinez N.,Central University of Venezuela |
Herrera P.,University Simon Rodriguez |
Colmenares O.,University Romulo Gallegos |
Birbe B.,University Simon Rodriguez
Zootecnia Tropical | Year: 2010
To evaluate the effect of the supplementation with multinutritional blocks (MB) on milk production, 20 dual purpose cows were used with breeding and 1 or 2 calving, in hilly area of the central plains of Venezuela. The experiment was carried with duration of 60 days of supplementation and 30 additional days of evaluation. A completely randomized design was used, with two groups: Control group (CG) (n=10): animals with ad libitum basal diet and Experimental group (EG) (n=10): animals with diet basal ad libitum plus MB. Sold milk and consumed by the calf were measured, and used to estimate total milk. As basal diet these animals were in paddocks with species like Cynodon nlemfuensis, Panicum maximun, Andropogon gayanus, Brachiaria arrecta and Dichanthium aristatum, and consumed milled hay of Cynodon nlemfuensis and crop residues of Sorghum bicolor in corrals. The chemical composition of the MB was: 29,6% of crude protein, 2,1% of ethereal extract, 16,9% of DNF, 9,9% of calcium and 2,5% of phosphorus. The average of MB intake was 67,92± 21,41 g.100 kg-1 live weight. The effect of treatment was significant in the milk consumed by the calf (P<0,01), with EG=1,17 ± 0,34 and CG= 0,75 ± 0,36 kg; sold and total milk did not show significant differences between treatments (P>0,05). A tendency exists to the increase in the milk production in supplemented cows with multinutritional blocks in these conditions, evidenced in the consumption of milk by the calf.
Rodriguez-Parilli S.,University Romulo Gallegos |
Velasquez M.,University Romulo Gallegos
Entomotropica | Year: 2012
With the aim to estimate the contribution of biomass, bees were collected weekly during 8:30 am to10:30 am, from August 2007 to July 2008. The collected biomass was 66 748.4 mg distributed in four families: Apidae 65 434.6 mg, Colletidae 5.5 mg, Halictidae 541.3 mg and Megachilidae 706.7 mg. The major contribution of biomass was of Xylocopinae (67.30 %). The Shannon-Wiener's diversity (H') was 0.68 and Pielou's equity (J') 0.37. A minor diversity and equity exists, as well as also a variation of the dominant bees as result on having used the biomass as variable of calculation and not the abundance. © 2012, Sociedad Venezolana de Entomología.
Rodriguez-Parilli S.,University Romulo Gallegos |
Velasquez M.,University Romulo Gallegos
Zootecnia Tropical | Year: 2011
The bees use diverse materials from the nature to support their metabolism, nests construction and/or defense. To know these sources is very important for the management of the apiculture and meliponiculture in order to guarantee the pollination of cultivated and not cultivated plants. The purpose of this study was to determine the bees' activity places in dry tropical forest of Guárico State in Venezuela. The sampling began in August 2007 and finished in July, 2008, with 8 hours effort/month. Bees were captured in 72 places through a transect of 500 m long. Results show that 65% of plants encountered represent species of plants distributed in 30 families. In Fabaceae (15 sp.), Asteraceae (6 sp.), Rubiaceae (4 sp.) and Malvaceae (4 sp.) recording the major numbers of species visited by bees, which represent 44,61% of the botanical species determined in the study and which received the visit of 35,58% of the bees. Apinae was the group more polilectic including 28 vegetable families visited, followed by Xylocopinae and Halictinae with 21 and 20 families respectively. The most important vegetable species for the bees, considering a frequency of visiting bigger than 100 individuals, were Amaranthus spinosus, Vernonia brasiliana, Hyptis sp. and those with higher diversity of visiting, including more than 13 species were V. brasiliana, Sida sp., Casearia sp., Wedelia caracasana.
Gomez Z.T.,University Romulo Gallegos |
de Rios M.V.,University Romulo Gallegos |
Gorayeb I.,Museo Paraense Emilio Goeldi
Entomotropica | Year: 2010
Arrieche-Luna E.,Instituto Nacional Of Investigaciones Agropecuarias Inia |
Ruiz-Dager M.,University Romulo Gallegos
Agrociencia | Year: 2010
Inappropriate soil management practices that have been applied in the Yaracuy River basin, Venezuela, have led to the loss of soil organic matter and crop productivity. The incorporation of composted organic residues has been suggested as an alternative management practice in order to increase organic matter (OM) content and crop yield in these soils. The objective of this study was to determine the effects of different application rates of an organic fertilizer obtained from sugarcane industry wastes, filter cake and bagasse with or without inorganic fertilizers, on microbial biomass carbon (MB-C), soil organic carbon (SOC), maize (Zea mays L.) yield and N, P, K content in the maize leaves, in Yaracuy River basin. The experiments were established in an acid soil and an alkaline soil, both of them with low OM contents. The experimental design was a randomized complete block with seven treatments and three repetitions. It was found that the highest MB-C, SOC and maize yield were obtained with the combination of organic and inorganic fertilizers: 160 kg N ha-1 + 120 kg P2O5 ha-1 + 80 kg K2O ha-1 + 2000 kg ha-1 organic fertilizer. In the alkaline soil this treatment increased the MB-C and SOC with respect to the control by approximately 97 %, and 43 %, and in the acid soil by 48 % and 43 %. A linear statistically significant correlation was found between MB-C and the SOC in the alkaline soil. Maize yield and MB-C, N, P, K content in the maize leaves were found to be significantly correlated in both soils.
Bess (Hymenoptera: Apoidea) visitors of Waltheria americana L. (Sterculaceae) in Rómulo Gallegos Universitys agricultural area, guárico, Venezuela [Abejas (Hymenoptera: Apoidea) visitantes de waltheria americana L. (Sterculaceae), en área agrícola de la Universidad Rómulo Gallegos, guárico, Venezuela]
Rodriguez-Parilli S.A.,University Romulo Gallegos |
Graterol M.R.,Bolivarian University of Venezuela
Zootecnia Tropical | Year: 2011
The bees are important animals in the pollination of them natural and cultivated plants, inclusive they have established specific relations, appearing botanical important species in the sustentation of bees's populations. The intention of this investigation was to identify the bees (Hymenoptera: Apoidea) visitors of W. americana L. (Sterculaceae) in agricultural area of the Rómulo Gallegos University, Guárico, Venezuela; in order to evaluate the potential of this plant in the managing of the bees. An area was established by 10 plants of W. Americana and all the visitors bees of this plant were collected with insect-net. The samplings were done between the hours 6:00-14:00, during October-November months (2008) by eight samplings for month. There were collected 3009 individuals distributed in four families and 40 species of bees, correspondents to: Apidae 2785 individuals, 22 species; Halictidae 186 individuals, 11 species; Megachilidae 35 individuals, five (5) species and Andrenidae three (3) individuals and two (2) species. Apis mellifera turned out to be the most frequent specie (52,21%). Ten species of bees (25% of the richness) 2835 individuals add up. W. americana is a specie of great potential for the maintenance of the richness and abundance of bees in the agricultural areas of the Rómulo Gallegos University.
Manrique A.J.,Federacion Bolivariana de Apicultores de Venezuela FEBOAPIVE |
Colmenares O.,University Romulo Gallegos
Zootecnia Tropical | Year: 2014
The present research was carried out from february 2009 to february 2012, in Experimental Station “Jaime Henao Jaramillo”, Universidad Central de Venezuela, located in Guaicaipuro municipality, Miranda state, Venezuela. Some colonies of bees (Apis mellífera) produce more propolis than others, and this characteristic is genetically controlled; usually these propolis are produced by scraping, doubt to in certain areas the nets are full of beeswax and not with propolis. The objectives were to select and improve (genetically) propolis collector bees, and to determine seasonality in propolis production, using collector plastic screen. Base population were 50 colonies of Africanized honey bees, being evaluated 25. The best colony was selected as parent of the next generation, evaluating 11 selected colonies (S1) versus 13 non selected colonies (NS1) the first year, and 11 selected colonies (S2) versus 13 non selected colonies (NS2) thesecond year. Obtained results indicated higher values of propolis production in S1 andS2, statistically differents (P<0.05) to NS1and NS2, with averages of 623.36; 684.45; 365.61 y 420.61 g of propolis/colony/year, respectively. The propolis production was superior during December, January and February. Determined the bees respond to selection to improve the propolis production, there was seasonality collection propolis and the used nets were useful to collect them, in the evaluated conditions. © 2014, Instituto Nacional de Investigaciones Agricolas (INIA). All rights reserved.