REPUBLICA BOLIVARIANA DE VENEZUELA
Venezuela is on the northern tip of South America between 0º45 and 15º 40 N, and 59º 45 and 73º 25 W. Its surface area is 916,445 km2, of which 882,050 are continental. It borders on the Caribbean Sea and the Atlantic Ocean to the North, and Colombia, Brazil and Guyana to the West and South respectively (see Figure 1).
Venezuela is a federal nation, including 23 States and a Federal District. Its population in 2001 was 24,600,000 (World Bank, 2001), and its rate of population growth 1.9 percent per year. According to the World Factbook the population in July 2006 was 25,730,435 with a growth rate of 1.38%. The urban population is 87 percent of the total. The valleys and piedmont of the Coastal Mountains (Cordillera de la Costa) and the Andean mountains ("Cordillera Andina") contain 60 percent of the population, whereas people are much sparser in the large basin of the Orinoco and Apure rivers. Over 40 percent of the population is in the largest eight cities On the other hand, only 1.5 percent of the population, including the majority of the indigenous population, is located South of the Orinoco River and in the State of Zulia (bordering the South and West of the Maracaibo Lake).
The gross internal product is approximately US$ 5,100 per capita (World Bank, 2002). Industry contributes 50 percent of the total, services 45 percent and agriculture only 5 percent (CATIE/FAO, 2000; World Bank, 2001). Venezuelas human development index was 0.765 in 1999 (UNDP, 2001). In spite of a long agricultural tradition, starting with the Spanish colonization, the discovery of oil in the Llanos or western Plains led to the present day economic importance of the industrial sector.
Venezuela's abundant farmland and temperate climate provide ideal conditions for agriculture. However, as oil came to dominate the economy, agriculture languished and, during the oil-boom years of the 1970s, imports of agricultural products rose rapidly. The sector today only provides less than five percent of GDP, whereas four decades ago it was one of the main backbones of the economy. Even though today approximately only one-fifth of the land is used for agriculture, it remains an important source of employment (around 14 percent of the labour force). More than half of agricultural income is from cattle ranching, while dairy products, fruit, grain, poultry farming and vegetables aggregated generate approximately 40 percent, with the balance coming from forestry and fishing.
Despite long periods when heavy subsidies were provided to the agricultural sector, Venezuela imports more than half of its needs for wheat, sugar, vegetable oil and yellow maize, with the United States supplying more than one-third of Venezuela's total food imports (LatinFocus, 2002). Nevertheless, the oil industry also led to the development of good infrastructure (roads, markets, communications, etc.) in the interior of the country (Pittevil and Buroz, 2001), which should facilitate agricultural intensification. Nearly 80 percent of Venezuelas income comes from oil (Venezuela, 1995). Other important mineral resources are bauxite and iron (CEPAL, 2001).
The agricultural area of Venezuela is variously reported as 21,600,000 hectares (FAO databases) to 34,600,000 hectares (Venezuela, 1995). The FAO databases report that 84 percent of the former figure is covered by permanent pastures, a fraction that remained stable over the last 20 years, while Venezuela (1995) estimated that 79 percent of the latter area was adequate for livestock production.
The number of ruminant livestock over the last decade has also remained fairly stable with some increases, and is shown in Table 1, whereas the production of beef and milk during the late 1990s decreased somewhat in a difficult political and socio-economic scenario (Table 1).
Table 1. Stock of ruminant animals (FAO databases, 2006)
The most important region for livestock production is the Llanos (see section 3, below), which contains 8,200,000 cattle, 270,000 sheep, 50,000 buffalo and 78,000 goats (Pittevil and Buroz, 2001).
Table 2. Production of beef and veal and cow milk, and beef and veal and milk imports in Venezuela, metric tons selected years 1985-2005 (FAO databases, 2006)
Important crops, in decreasing order of sown area, include maize, coffee, sorghum, sugarcane, rice and cassava (CEPAL 2001). Several species and types of bean, although sown in smaller areas, are important components of the diet.
Beef consumption per capita is 17.3 kg/year (FAO, 1999), a figure slightly below the average for South America (in 1996), and milk consumption is 82 l/capita.year (Paredes, 2002).
As indicated above, Venezuela is a land-rich country with a highly urbanized population, employed mostly in industry and services. Nevertheless, despite agrarian reform efforts that began in 1960, Venezuela's land tenure patterns in 1990 still portrayed the typical Latin American dichotomy between latifundios and minifundios (small holdings) as shown in Table 3.The country's major land reform programme began with an initial decree in 1958, and the Agrarian Reform Law of 1960 created the National Agrarian Institute (Instituto Nacional Agrario--INA), which sought to provide land to those who worked it, initially by transferring public lands and later by expropriating private holdings of arable land not under cultivation. Despite the provision of roads, markets, schools, and clinics, new agricultural colonies rarely had the conveniences of earlier farming towns and only modest progress was realized. The average size of the country's 400,000 farming units stood at eighty hectares in 1989, considerably higher than earlier decades but, according to the 1998 census, the average was 60 ha/farm (Pittevil and Buroz, 2001). Venezuelas Gini coefficient in the 1990s stood at 0.54.
Table 3. Land tenure in Venezuela as of 1985. Modified from Delahaye (1996)
As indicated above, agricultural production is relatively less important in Venezuela than in the rest of Latin America, and the sector has also grown only at very modest rates, as inferred from Table 4, which also shows several important macroeconomic indices.
Table 4. Important macroeconomic indicators of agricultural resources and production, 1990-2000 (CEPAL, 2001)
|2. SOILS AND TOPOGRAPHY
Six different relief formations are recognized (CATIE/FAO, 2000):
The main natural regions are shown in Figure 2.
Figure 2. Natural Regions of Venezuela
There is considerable variation in Venezuelan soils, partly linked to the geology of each region. Agricultural use of soils is constrained by a number of limitations: 4 percent of the territory is arid, 18 percent has drainage limitations, 32 percent are soils of low fertility, and 44 percent is on steep slopes, thus leaving only 2 percent without limitations (Casanova et al., 1992).
The geologically oldest formation is that of the acid Guyana shield to the south of the Orinoco River, frequently identified as the Pantepui Region, it extends into north-western Guyana and northernmost Brazil. The geology consists of a mainly granitic Precambian base (the Guyana Shield), overlain by younger sedimentary sandstones and quartzites of variable thickness. This gave rise to very infertile, leached soils that include: (a) soils of the flat-topped table mountains ("tepuys") and the Gran Savanna, characteristically very sandy, with extremely low organic matter content; (b) mountain clay-sand soils, derived from granite and gneiss and (c) soils along the Orinoco River, influenced by alluvial sediments.
Along the more recent Andean region (the Andes, the Interior Chain and the Coastal Chain), soils are newer than those of the Guyana shield but have been altered by erosion, particularly in the piedmont, where human intervention has been drastic through deforestation.
In the oldest plains or Llanos (Eastern and Central Plains, and the Plains of the Meta River) oxisols predominate, frequently with very superficial horizons and an underlying ferrous layer. The more recent plains (Western Llanos, and South of Lake Maracaibo), some of the best soils are found. These are deep relatively fertile soils, though may have drainage limitations during the peak of the wet season.
The delta of the Orinoco River includes soils limited by salinity and by the presence of high sulphate concentrations.
Utilization of soils along much of the coast is severely limited by low rainfall. Soils are mostly superficial litosols, or poorly developed entisols, very low in organic matter and P.
A large proportion of soils in Venezuela are acid (Table 5) and therefore have low cation exchange capacity, are low in P and frequently in several bases.
1Data includes samples from several States, as
AND AGRO-ECOLOGICAL ZONES
Venezuela has two very large and important catchments, those of the Atlantic Ocean and the Caribbean Sea respectively. The Atlantic Ocean Catchment, which receives the Orinoco and several other important rivers, covers 82 percent of the territory, with 70 percent drained by the Orinoco (see Figure 3) , which divides Venezuela in two. The Caribbean catchment, receives water from several smaller basins, including the Maracaibo Lake and those that drain the northern portions of the mountains. Although it covers only 17.5 percent of the territory, it is extremely important as it is densely populated.
Figure 3. The basin of the Orinoco River, including the Colombian portion
The geography of Venezuela is relatively complex, and detailed analyses recognize 27 climatic zones, 12 types of vegetation, 23 of relief and 38 geologic units (Venezuela, 1995). In a broader analysis, the following ecozones (see Figure 4) are generally recognized (FUDENA, 2001):
Figure 4. Ecoregions of Venezuela
a) Maracaibo Lake and the Coro System
These two regions are extremely variable in terms of landscape and climate. The Coro system includes the States of Falcón, Lara and parts of Zulia, Yaracuy and Carabobo. It is a combination of mountains, valleys and plains with the highest altitude at 1,900 metres. Rainfall between 500 and 1,500 mm, and average temperatures between 20 and 28 ºC. At sea level, it can be quite hot. Mountains are covered by forest, that evolves to dry forest in the driest altitudes towards the coast where the vegetation is xerophytic to desertic. Lake Maracaibo is well known for its oil deposits. The landscape around it is very variable. In the west, towards the Colombian border, the vegetation is xerophytic to desertic, with rainfall amounting to no more than 250 mm. This gradually increases to 1,000 mm in the plains surrounding the city of Maracaibo. At the western extremity of these plains the vegetation evolves towards premontane and tropical forests. Dense tropical rainforest are found south of the Lake.
This region contains one third of the countrys sown pastures, and produces 60 percent of the milk, 80 percent of which comes from 20 percent of the farms (Betancourt et al., 2001).
b) South of the Orinoco River
This is a large region covered by the Guyana Shield, one of the oldest (1,500,000,000 years) geologic formations. Towards the (eastern) border with Guyana, the predominant vegetation is savanna, with deciduous forest which alternates with mesophyll forests in the lower areas as well as south in the area that borders with Brazil. Here is also found the Gran Savanna, or plains located above 1,000 metres. A characteristic geologic formation of the ecozone are the flat-topped table mountains known as "tepuys", which rise to heights of 1,300-3,000 metres and are frequently covered by a diversity of forest formations. Throughout the ecozone the vegetation tends to be exuberant despite the poverty of the soils, and plant biodiversity is very high. It is estimated that it includes over 9,000 species of trees, shrubs and herbs. Despite its size, the region is unimportant from an agricultural point of view, but mineral resources are important (e.g., bauxite), as is ecotourism.
The Llanos. This ecozone is distributed between Colombia and Venezuela and extends over 355.112 km2, 68 percent of which is in the latter country. From an ecological point of view it includes some of the largest wetlands in the world, and constitutes a major reserve of water.
The Llanos cover approximately 75 percent of Venezuela, house only 16 percent of the population( 15 persons/km2, ranging between 6 and 50 depending upon the State) but nevertheless contribute the largest portion of cereal and livestock production of the country. The extent to which the Llanos have been developed varies greatly between States. Although cattle, cereal and oilseeds are more or less common to all, cattle constitute the main economic activity in the States of Barinas, Guárico and Apure, cereals production is dominant in Portuguesa and Cojedes, and oilseeds in Monagas and Anzoategui.
The Andes. In reality, the Venezuelan Andes are a group of ecoregions common to the highest parts of the tropical Andes and intermontane valleys that extend through Venezuela, Colombia, Ecuador and northern Peru covering 49 million hectares (the "Green" Andes). The region is of worldwide importance as one of the principal centres of endemism and contains close to one half of the plants, birds, butterflies and frogs of the neotropics, as well as constituting a major source of water. In Venezuela it includes two distinct regions: the montane forests, and the Páramos of Mérida, which are mainly differentiated by altitude. Part of the area drains towards Maracaibo Lake, and the rest to the Orinoco.
The Coastal, Central and Eastern, Andes. This is where Caracas, as well as several other important cities are located. Therefore, it is probably the region that has suffered most intensive human intervention, resulting in widespread erosion, sedimentation of valleys and considerable contamination. The Southern slopes descend into the plains or Llanos. Depending upon the variable rainfall, they may contain rich cloud forests, or dry montane forests. The valleys house approximately 40 percent of the human population and a higher proportion of economic activities. In the intermontane valleys, sugar cane is the most important crop, followed by horticultural crops and orchard. Warmer parts grow cocoa, plantain and root crops.
The Coastal area includes arid regions located between the Caribbean border with Colombia to the Gulf of Cariaco. Equally arid areas are located in the Venezuelan islands, some dry Mesas in the Andes, and the highlands of Barquisimeto State. All together, these areas amount to 41,023 km2 (Matteucci and Colma, 1997).
RUMINANT LIVESTOCK PRODUCTION SYSTEMS
Ruminant based systems can be found in over 42 percent of the national territory (Thornton et al., 2002), with rangeland-based systems occupying 26 percent of the surface area, mixed rainfed systems 15 percent, and irrigated systems 1 percent.
A general overview of traditional cattle production systems in Venezuela summarized by Chacón (cited by Betancourt et al., 2001) is shown in Table 6.
Table 6. Average productivity of cattle production systems in different ecozones. Source: Betancourt et al. (2001)
*Rotationally grazed well managed kikuyu pastures; cows supplemented with concentrates according to milk yield
Although specialized beef and dairy systems exist in Venezuela, the majority of small and large ranches have a high proportion of crossbred, Bos taurus x B. indicus cattle (sometimes called "mosaic"), of which a proportion of lactating females may be milked. Even large ranches dedicated to cow-calf operations frequently include a proportion of crossbred cows regularly milked. These "dual purpose" systems are common to all tropical countries of Latin America, with some variations to accommodate local circumstances. Typical dual-purpose systems in the tropical lowlands use crossbred females that are hand-milked most frequently once a day with the calf on foot to stimulate milk letdown. Following the morning milking, cows and calves are generally pastured until the afternoon when calves are separated from their dams and yarded until the following morning. The amount of milk collected in the morning milking, generally represents 50 percent or more of the total milk produced by the cow. Common variations on this basic system may involve machine milking, particularly in cows with a high percentage of Bos taurus, restricted suckling by calves to 30 or more minutes once or twice a day. This system is of major importance in Venezuela, and it is estimated that it provides 95 percent of the milk produced (Betancourt et al. 2001). Vaccaro (1986) reviewed the literature covering 1306 dual purpose farms in 8 countries of tropical Latin America and the summarized results (Table7) apply well to Venezuela.
Table 7. Characteristic parameters of dual-purpose milk and beef systems in tropical America. Source: Vaccaro (1986)
The largest stock of cattle is in the State of Zulia and around the Maracaibo Lake (Zulia contains 22 percent of the national stock), but since most cattle are dual purpose, the state is more of a milk, than a beef producer. Numerous surveys have been conducted in this area with the aim of further characterizing dual-purpose systems and identifying possible entry points for technological and managerial improvements. Carrizales et al. (2000) surveyed dual purpose systems biased towards milk production among farms providing 55 percent of the milk received by an important dairy processing plant in the most important municipal district south of the Lake, and grouped the results according to farm size (range 15-400 ha), as shown in Table 8.
Table 8. Characteristics of dual purpose systems South of Lake Maracaibo (Santa Bárbara). Source: Carrizales et al. (2000)
The above results demonstrate the upper limits of this type of system, particularly in small to medium farms located in a favoured environment, that attempt to maximize yields within the constraints of current costs.
These systems in the area of influence of Lake Maracaibo are essentially grassland-based, but the relative importance of pasture species and management practices vary according to climatic conditions. Thus, Peña et al. (1999) reported that in the drier portion (dry tropical forest), as well as in the region of humid tropical forest, Panicum maximum was the dominant species (65 and 57 percent of sown pastures respectively), whereas Brachiaria species increased from 3 to 16 percent in the above two subregions, and were the main species (56 percent) in the very humid tropical forest subregion. Forage conservation (hay and silage) was practiced by 54, 41 and 10 percent of the farms respectively, with stocking rates increasing from 0.6 to over 1 AU/ha in the same order. The previous set of characteristics and patterns apply with some modifications to the rest of Venezuela as well. Although in general over 50-60 percent of farmers live on-farm, frequently farmers in relatively less favoured areas (e.g., parts of the Llanos) may work off-farm as well (in some areas > 40 percent), frequently in the oil industries. The importance of family labour in these dual purpose systems varies between regions, ranging between 50 and 100 percent.
The early evolution of the agricultural development of the Llanos was discussed by Crist (1983, 1984 and references therein).
Beef production systems, essentially cow-calf systems selling yearlings and with limited fattening of steers, tend to concentrate on the poorly drained savannas of the alluvial overflow plains of the southwest, and on the high mesas and plains of the north-eastern Llanos (see section 5 for descriptions). In both cases, systems are extensive in the use of land, and a large portion of the capital invested is represented by cattle. Beef systems on the high mesas were studied in detail in the early 1980s and little further, up to date information is available. Plessow (1985) collected detailed information on 15 representative ranches located in the States of Monagas and Anzoátegui, averaging 1,533 hectares each (range 516-4,664) that included 57 percent of the area in high savanna (well drained year round), 33 percent of lowland savannas partially flooded in peak rainy season and 10 percent of forests, mostly gallery forests along water courses. Close to 80 percent of the area as covered by native pasture, and the rest with sown species (Brachiaria decumbens and Digitaria decumbens, the latter frequently fertilized at a time when subsidies were substantial) with very small areas of sorghum in some cases. Since then there has been a major, but unquantified replacement of the above sown pastures with Brachiaria humidicola and to a lesser degree Brachiaria brizantha. On average these farms carried 610 AU, 90 percent of which were the breeding herd, heifers and yearlings. But even in these systems, out of the 263 cows present on average, 60-80 depending upon the season, were milked, thus constituting a hybrid system between a purely beef system and a dual purpose one. The availability of pastures averaged 3.12 hectares per AU, including 2.77 hectares of native savanna and 0.4 hectares of sown pastures. Average production parameters are shown in Table 9.
Table 9. Average production parameters for cow-calf system in the high Llanos of Venezuela. Source: Plessow et al. (1985)
The study concluded that nutrition, and therefore the quantity and quality of the forage, was the main biological constraint of these systems, a view that is supported by the widely recognized low nutritional value of these savannas. Thus, improvements in biological performance would have to rely much more on the improvement of forage resources, via sown pastures, than on the limited scope for improved savanna management.
Sheep production systems are far less important in Venezuela than cattle systems, and there is limited information about them. Rondón et al. (2000) summarize results of 74 farms owning more than 15 sheep each and located across the central and western parts of the Llanos with annual rainfall ranging from 728 mm to 1,325 mm. These farms averaged 260 hectares each, and 19 percent of the surface area was allocated to sheep production. Tropical meat breeds predominate, including West African, Barbados, Barriga Negra, Persa Cabeza Negra and numerous crosses among them. Animals of the wool breeds Bergamasca and Dorset were far less common. In the smaller farms, sheep were for household consumption, whereas larger properties had a commercial orientation. Forage resources across these farms were very variable, including 22 percent that used only pastures, 16 percent that supplemented pastures with concentrates, and 19 percent that supplemented with agroindustrial residues.
The Andean region has peculiar production systems. Until the arrival of the Spanish colonization, the Andes were used for agricultural production up to an altitude of 3,000 metres (Monasterio and Molinillo, 2001), but subsequently their use extended above that height. Three altitudinal levels are distinguished, but farming systems may frequently occupy the two lower levels. The Andean region between 2,000 and 3,000 metres concentrates on the production of tubers, horticulture and floriculture in the most fertile, flat areas, that are irrigated thanks to re-routing of watercourses. The slopes are covered with communities of shrub-rosettes to pure shrubs, which extend into the second level, the High Andes (3,000-4,000 metres) which constitutes the upper limit for agricultural production. Here crops such as potato are rotated with fallows utilized by cattle a proportion of which is used for animal traction. The native grasslands are constituted by shrubs such as Espeletia schultzii, Hypericum laricifolium and Acaena elongata, and a herbaceous layer of Festuca myurus, Stipa mexicana, Luzula sp. Poa sp., Calamagrostis sp., Geranium sp, and Rumex sp. (Molinillo and Farji-Brener, 1993; Molinillo and Monasterio, 1997). In this area a type of extensive, and very variable pastoralism is practiced which combines intensive use of gramineous grasslands in the valley floors with extensive use of the rosette-shrub communities on the slopes. Fallows and crop residues are used during the dry season when native forage is scarce. It is considered that improved animal and grazing management, rather than elimination of pastoralism, is essential to the preservation of the ecosystem.
Lastly, goats are concentrated in the arid regions of Venezuela, and are raised in extensive systems that make free use of arid rangelands. They constitute the main source of income, which is complemented with subsistence agriculture and handicrafts. The use of native vegetation by humans and goats for fuel, construction and grazing has provoked considerable desertification of some of these areas.
|5. THE PASTURE RESOURCE
As indicated in section 3, Venezuela has a rich flora. This includes grasses, and particularly herbaceous legumes that have been amply collected for characterization and eventually, breeding improved forages in a variety of tropical countries. An ample list of native species that have potential as forages is available (Venezuela, 1995).
Venezuela has an estimated 11,000,000 hectares of native pastures (52 percent in the well drained Llanos, and 48 percent in the poorly drained savannas) and 6,000,000 hectares of sown pastures, 75 percent of which are distributed between the Andean region and the Maracaibo basin and neighbouring areas (States of Zulia, Falcón and Portuguesa).
The Llanos of Venezuela are part of the 50,000,000 hectares of savannas found in the basin of the Orinoco River. Sarmiento (1994) has traced their development through geological eras. The Venezuelan Llanos are amongst the better-studied neotropical savannas, and an extensive literature is available which, among others, has been reviewed by Sarmiento (1983, 1994, 1996). Numerous vegetation communities have been classified and mapped, but for the purpose of this profile, the classification of the Llanos into four main subregions by Sarmiento is appropriate.
The first subregion is that of the Piedmont Savannas, which consists of large alluvial areas and terraces covered originally by semi deciduous tropical forests and savannas, though the latter predominates. As indicated by their name, they are located S.E. of the Andes and gradually descend into the plains. They are characterized by a rich flora of trees (e.g., Acrocomia sclerocarpa, Bowdichia sp., Byrsonima sp., Casearia sylvestris, Curatella americana among others), shrubs (e.g., Clitoria guianensis, Desmodium pachyrrhiza, Galactia jussieana, etc.) and numerous grass species most of which are common also to the other types of savanna. These include Andropogon selloanus, Andropogon semiberbis, Axonopus canescens, Axonopus purpusii, Bulbostylis spp., Elyonurus adustus, Leptocoryphium lanatum, Panicum olyroides, Paspalum plicatulum, Paspalum gardnerianum, Trachypogon plumosus, Trachypogon vestitus and Trachypogon montufari. On average, the maximum aboveground stand of savanna reaches seven ton/ha.yr, with about twice that amount below ground (to two metres).
The savannas of the High Plains or Mesas are located immediately north of the Orinoco River at 150-270 metres, descending into a lower portion identified as "Llanos de Monagas". The relief varies from gently undulating to dissected hills. It is covered by a seasonal tree savanna where the herbaceous layer predominates. The latter is dominated by Trachypogon plumosus or T. vestitus, (thus the name "Trachypogon savannas") with Andropogon selloanus, Axonopus canescens and Leptocoryphium. lanatum as subdominant grasses. Overall, 95 species of 29 families have been identified (Berroterán, 1988), but the Poaceae constitute the largest group with 33 species. Although Papillionaceae are the second largest group of species (Centrosema angustifolium, Desmodium incanum, Desmodium pachyrhizum, Stylosanthes spp., Zornia spp.), their presence is low. The scarce layer of trees is composed of Curatella americana (possibly the most characteristic species), Byrsonima crassifolia and Bowdichia virgiloides. Primary above-ground production of the grass layer peaks at 3,200-4,200 kg/ha when burnt, whereas yields are 30 percent lower if protected from fire. Fire is the only economically feasible management tool available. Burning, even in mid dry season, induces a regrowth if water reserves allow, which is faster than if mown (Medina and Bilbao, 1996)
The Alluvial Overflow Plains occupy a vast depression of 3,800,000 hectares (Flores and Argenti, 1987) in the central part of the Llanos between the piedmont and the high plains. It is a very flat area which shows differences of only 1-2 metres between the highest and lowest points. The upper part constitute natural levees where the soil is a sandy alluvium, whereas the lower parts (basins or cuvettes) settle the clay particles and have therefore slow drainage. Consequently, rainfall drains very slowly, the lower parts remaining flooded during most of the rainy season, but have a high carrying capacity during the dry season. The area is used exclusively for extensive cattle and buffalo grazing (96 percent of the area for cattle, 4 percent under forests; Tejos, Schargel and Berrade, 1990), although frequently free ranging, wild, capybara (Hydrochoerus hydrochaeris) are raised together with cattle. The botanical composition of levees and basins is different but in general this type of savanna has more palatable species than the rest, and it has been modified somewhat by human intervention. Intervention has been most pronounced in an area of approximately 250,000 hectares which have been enclosed by low dikes and floodgates to regulate water levels in sections of 3,000 to 6,000 hectares each (these sections are known as "módulos"; Torres et al., 1987; Tejos, Schargel and Berrade, 1990). Average soil chemical compositions ranges between 4.6-4.7 for pH, 1.4-2 percent OM, 6-8 ppm P, 36-62 ppm K and 36-69 ppm Ca. The sections of the microrelief permanently above water are colonized by Axonopus purpusii, Axonopus affinis and Leptocoryphium lanatum; sections moderately flooded contain Panicum laxum, and Leersia hexandra as dominant species, and the strongly flooded areas are dominated by Hymenachne amplexicaulus, Reimarochloa acuta and Leersia hexandra, together with cattle. Cyperaceae are also abundant. Aboveground yields vary between the 5 tons DM/ha of the levees to 2-3 tons in the basins. According to some estimates (Torres et al., 1987) regulation of water level in the Modulos can increase carrying capacity up to five fold.
The Aeolian Plains are an area that extends north-east from the Colombian Andean Piedmont into Southern Venezuela. It is characterized by extensive dunes covered by a sparse vegetation, almost treeless, and dominated by Trachypogon ligularis and Paspalum carinatum whereas the inter-dunal depressions are occupied by a Mesosetum savanna. Both formations are low yielding and of low palatability.
As indicated in section 3 the original vegetation of these two regions varies from dry to very humid tropical forest, with few herbaceous species. Nevertheless, much of the area has been heavily deforested due to the existence of valuable timber. Subsequently, adventitious grasslands developed in areas where pastures were not purposefully established. Recent collections of grass species along the subhumid to very humid areas have identified grasses that are common throughout the humid lowlands of tropical America. González and Piña (1995) collected grass species across a gradient of rainfall from 1,300 mm to well over 1,800 mm, and found that Paspalum virgatum is very widely distributed. Another well known tropical species, Homolepsis aturensis (found in most of the Amazon basin as well) was also widely distributed on acid, well-drained soils, and Imperata contracta was found in more infertile soils with even lower pH. Reputedly good quality species such as Leersia hexandra and Hymenachne amplexicaulus were limited to the better soils. Nevertheless, it was found that 82 percent of the farmers surveyed in the region attempted to replace native species with introduced grasses. Fire and overgrazing constitute the first step in this process.
Sown species vary according to climate and soil conditions. On well drained, relatively fertile soils which generally coincide with lesser amounts of rainfall, Panicum maximum is generally the preferred species, distantly followed by Echinochloa polystachya, Digitaria spp. and Brachiaria spp. Mixtures of two or more of these species are very common. In the wettest areas, Brachiaria spp. (B. humidicola, B. decumbens and B. brizantha, possibly in that order) dominate sown pastures, sometimes in mixtures as well. Legumes are very rarely used, although in the early 1990s it was clearly shown that Desmodium ovalifolium was a valuable forage in this environment.
Research on improved forages for the arid parts of this ecozone, along the coast, has been limited. Forages such as Stylosanthes hamata, Leucaena leucocephala, Macroptilium lathyroides, Pennisetum typhoides, Cajanus cajan and Cenchrus ciliaris have given promising experimental results. Buffel grass for example, has been shown (Matteucci and Colma, 1997) to support 10 goats/ha.year, which can potentially be complemented with some of the native leguminous trees (Prosopis juliflora, Acacia tortuosa, Caesalpinia coriaria).
|6. OPPORTUNITIES FOR IMPROVEMENT OF FODDER
In the late nineteen-eighties and early nineteen-nineties over a thousand accessions of forage grasses and legumes were introduced to Venezuela, largely for agronomic evaluation (Chacón, 2000). A few of these, most notably Brachiaria humidicola and Andropogon gayanus were rapidly and widely adopted by farmers and ranchers, whereas the eventual use of herbaceous and tree legumes remains a major challenge across all ecozones. Improved management of the above species, as well as of existing forages appear to offer considerable scope for increasing ruminant production, as shown by demonstrations carried out on-farm (Betancourt et al., 2001), based on intensive rotational grazing, and summarized in Table10.
Table 10. Grassland-based animal productivity realized in on-farm demonstrations. Source: Betancourt et al. (2001).
Sylvopastoral systems have been widely promoted for improving forage resources, particularly in dual purpose systems, and have demonstrated considerable potential. For example, Ojeda and Escobar (1997) reported that in the association Cynodon nlemfuensis-Gliricidia sepium, the legume successfully replaced most of the soybean offered in the concentrate supplement consumed by cows yielding 9 kg saleable milk per day. Similarly, in the drier areas and where soils allow (e.g., on alfisols with little free Al, otherwise of low to moderate fertility) Leucaena leucocephala has provided high biomass yields of equally high quality. Nevertheless, if cows in dual purpose systems have moderate milk potential (< 10 kg/day) and if grass paddocks are constituted by high quality, well managed species such as Cynodon sp., Digitaria decumbens and Panicum maximum, the effects of supplementation with the legume tree have not been significant in many cases. These variable results point to the existence of considerable interactions in terms of expected results between the grass, the forage trees and animal genotype, issues that are still poorly documented. Also, adoption of these, or similar systems, in situations in which the legume tree(s) have to be established, is questionable as opposed to systems where there is already a natural stand of the trees.
There is some evidence that successful improvement of at least some grassland-based dual purpose systems may depend relatively more on improved management and organization of existing resources rather than on the adoption of new, hard, pasture technologies. Thus, in at least some cases, appropriate seasonal adjustment of rest and grazing periods of existing pasture resources appear to be critical to superior performance.
In the high Andes (1,000-3,500 metres), where moisture permits or where irrigation is available, species such as kikuyu grass (Pennisetum clandestinum) and various Lolium spp and hybrids have been tested. Kikuyu in particular is regularly used by farmers, particularly for dairy cows.
RESEARCH AND DEVELOPMENT ORGANIZATIONS AND PERSONNEL
Institutionalized agricultural research in Venezuela is a relatively recent development. It is traced back to 1936 when the first experiment station was created, which in 1961 gave rise to the national research institute FONAIAP (now INIA). It is interesting to note that the first survey of native grasses was undertaken in 1940 by the famous American agrostologist Agnes Chase.
Given the importance of ruminants and grasslands in Venezuela, research is carried out by a wide constellation of institutions. Nevertheless, in the late 1990s research on all aspects of forage production declined significantly relative to the 1980s and early 1990s when considerable resources were available (Tejos, 2000).
In 2000, 12 of the 18 experiment stations of INIA carried out research on dual purpose, beef and milk productions systems, and the institutes strategic plan for 2001-2006 (Chacón, 2000) includes research subprogrammes on cattle, and on sheep and goat systems, each of which includes forage research. INIA also has a well equipped central research institute, CENIAP, which provides leadership and centralized services.
Several large, national and regional, universities carry out relevant and active research on forage resources, livestock production systems, disciplinary areas and veterinary sciences. Among these, the following are noted: Universidad Central de Venezuela, UCV, in Maracay, focuses research on the Llanos; Universidad de los Andes, in Mérida, concentrates on research in the Andes and Piedmont; Universidad Nacional Experimental de los Llanos Ezequiel Zamora, UNELLEZ, focused on the western, most productive Llanos, and Universidad del Zulia (LUZ), located in Maracaibo and specializing on research around the lake. In the late 1990s these and other universities have taken a leading role in carrying out research on grassland-based systems, in parallel with re-organization, and reduced funding of INIA.
The national science council (Consejo Naconal de Investigación, Ciencia y Tecnología, CONICIT) supports basic research on a competitive basis:
Fondo Nacional de Ciencia, Tecnología e Innovación,
The Venezuelan institute for scientific research, IVIC, houses an international centre for tropical ecology, sponsored jointly by the Government and UNESCO, which has conducted a substantial amount of ecological research in the Llanos and elsewhere:
Centro Internacional de Ecología Tropical
A number of private foundations and institutes either provide financial support and/or carry out research, including:
This foundation, in addition to financing research, maintains a very complete agricultural library online
Fundación para la Investigación Agrícola, DANAC
Fundación Servicios para el Agricultor
The Ministerio de Agricultura y Cría is the ministry involved in formulating policies, and surveying the development of agriculture. The Ministerio del Ambiente y de los Recursos Naturales Renovables is the environmental executive branch, and it is active among other things, in mapping, surveying and prioritising the use of natural resources. It has a wealth of relevant information regarding soils, climate, vegetation, and others.
Important financial and manpower resources have been allocated at the national level to research on an important syndrome causing severe losses and limiting the productivity of cattle in the Llanos ("síndrome paraplégico"), associated with undernutrition, mineral deficiencies and possibly other causes.
Technology transfer and extension have undergone many changes and remains underdeveloped at the national level. Nevertheless most universities, particularly the regional universities, have effective on-farm research and cooperation with ranchers and farmers organizations.
Lastly, a large number of NGOs are active at the national and regional levels, with particular emphasis on the protection of natural resources. A most important one is FUDENA:
Fundación para la Defensa de la Naturaleza, FUDENA
Ave. Principal de los Cortijos
Centro Empresarial Senderos, Piso 6, Ofic. 611
use systems in the Andes, including cattle-potato systems:
National Research Institute:
Dual purpose systems, cattle management systems, genetics:
Sown tropical pastures, improvement, germplasm evaluation
in the area of influence of Lake Maracaibo:
Pastures in the Llanos, germplasm testing, sown pastures
Dr. Raul R. Vera is a former Senior Scientist and Leader of the Tropical Pastures Program, International Center of Tropical Agriculture, CIAT, based in Cali, Colombia. He is currently a private consultant and part-time researcher of the Catholic University in Santiago, Chile.
Raúl R. Vera
[The profile was prepared in January 2003 and lightly edited by J.M. Suttie and S.G. Reynolds in February, 2003 and slightly modified by S.G. Reynolds in May 2006]