Effect of dyke construction on water dynamics in the flooding savannahs of Venezuela

Abstract

In the flooded savannahs water is the main factor determining the ecosystem and its change. During flooding, the level of water and the duration of flooding are highly dependent on the relative height position of the ecosystem unit. To understand the spatial processes in the ecosystem one must know the water dynamics in the area. In order to quantify the water content during the year, a digital elevation model (DEM) is needed. Several areas in the Llanos de Orinoco have been dyked (modulos). A digital elevation model has been developed on a level of the dyked area of the modulo of Hato el Frio. Flooding has been studied at the regional level and a DEM has been developed for the modulo area. For the construction of the DEM various sources were explored for height information. Field measurements with GPS were necessary.After the high flooding period downstream of the dykes the area is totally dry. In the transition period between the dry and the wet season the distribution of water shows a clear influence of the dyke. In the natural situation the natural height differences create a complex system of sinks. The dyke construction has created a large artificial sink. Modulos form sinks by their banks preventing the outflow of the water. With the help of a DEM, inundation can be modelled with relatively little field research.

Fattening performance and carcass traits of implanted and supplemented grassfed bulls

“…With the construction of dikes (modules) to control floods and to have water available during the dry season [32], the native vegetation of the lower plains of Apure State (Venezuela) has been replaced with better forage (e.g., Brachiaria spp.) resources [21].…”

Crecimiento, características de la canal y calidad de carne de toros jóvenes de tres biotipos sometidos a reimplante y suplementación en sabana tropical mejorada

“…Modelos de suplementación (mineral vs. proteicoenergética) durante la fase de crecimiento no han afectado la calidad de la carne de toros (Torrecilhas et al, 2021). Sin embargo, en la zona de interés, con mejor infraestructura de irrigación (Smith et al, 2006) y el cultivo de nuevas especies forrajeras de mayor calidad nutricional que la vegetación nativa (Lascano, 1991; Tejos et al, 2005, se ha sugerido suplementar estratégicamente nutrientes deficitarios en el pasto (proteína, energía y minerales) para optimizar la respuesta animal (Byers et al, 1997; Chacón y Marchena, 2008. Por otra parte, el uso de implantes (esteroideos y no esteroideos) se ha evaluado ampliamente para acelerar crecimiento de bovinos bajo condiciones intensivas de clima templado (Johnson et al, 2013; Garmyn y Miller, 2014; Duckett et al, 2016; Smith y Johnson, 2020; Webb et al, 2020 y condiciones extensivas del trópico Pietrosemoli, 1991; MorónFuenmayor y RumbosGómez, 1997ab).…”

The Effects of Castration, Implant Protocol, and Supplementation of Bos indicus-Influenced Beef Cattle under Tropical Savanna Conditions on Growth Performance, Carcass Characteristics, and Meat Quality

“…The savanna ecosystem and the hydraulic infrastructure (grazing modules) in Apure State have been previously described [6,7,37], while others [1,38] have detailed the location of the experiments and its agro-climatic characteristics. Briefly, two experiments were carried out in a commercial ranch located at the Southwestern isohyperthermic savannahs of Venezuela, 25 km south of the Apure River between 7 and 8 • N and between 67 and 68 • W. The area corresponds to a tropical dry forest with an annual mean temperature that varies between 22 and 29 • C. The ranch has an approximate area of 25,000 ha, 8000 are flooded in the rainy months (May-October).…”

“…However, castration is encouraged by the Venezuelan beef carcass grading system [3] because only castrated males (steers) under 30 months of age (MOA) are eligible for the top carcass quality grade. Producers in the region of interest (Apure State) face environmental and managerial challenges to keep their cow-calf operations sustainable, despite major investments in crossbreeding programs [4,5] and pasture infrastructure improvements [6,7]. Within grazing systems, forage quality and quantity are the major factors affecting the metabolizable protein and energy allowable for body weight gain in ruminants [8].…”