Country Pasture/Forage Resource Profiles
Vanuatu is a Melanesian island republic in the south-west Pacific, consisting of 80 islands spanning 850 km from 13°S to 22°S and covering 12,200 km2 (Anon. 1994) (see Figure 1). The country has a population of 169,000 (Anon 1994), concentrated on 3 of the major islands, and a total land mass of 1.2 M ha of which 41% is arable (Anon 1994). In 1990, the agricultural sector contributed 23% of GDP and national exports continue to be dominated by agricultural commodities, primarily copra and beef and to a lesser extent cocoa and timber (Anon. 1994). Subsistence agriculture accounts for 43% of agricultural production and 80% of working age ni-Vanuatu (indigenous citizens) cultivate their own land for their livelihoods. The livestock sector is dominated by beef cattle production and contributes 12% to GDP and 22% to national exports. A national goat herd of 12,000 is reported but this figure may be a significantly overestimated.
The national cattle herd is estimated to be 151,000 of which 77,000 are owned by the smallholder sector (Macfarlane 1998) and the remainder by the plantation or large holding sector (>100 head of cattle) which includes both ni-Vanuatu and expatriate graziers. Larger holdings are concentrated on the islands of Efate and Espiritu Santo whereas smallholder cattle are widely dispersed but more prevalent on Espiritu Santo, Malo and Epi. The average ni-Vanuatu household owns 9 cattle, increasing to 13 on Espiritu Santo (Anon. 1994). Vanuatu has 2 export standard abbatoirs, based on Efate and Espiritu Santo, and exported 1,200 tonnes of beef in 1992, primarily to Japan, Papua New Guinea and Solomon Islands. Approximately 20% of slaughtered cattle are sourced from ni-Vanuatu producers. Quite a number of cattle are sold by subsistence farmers to regional butcheries or to villagers for traditional ceremonies and feasts (Anon. 1994).
buffalo meat and milk production,cattle imports and beef and veal imports
for the period 1991-97
Source: FAO Database 1998; n.r. = no record
Figure 1. Map of Vanuatu
The topography of the island chain is dominated by low mountain ranges oriented roughly in a north-south direction. Highest peaks generally range from 800-1200 m a.s.l. but increase to 1800 m a.s.l. on Espiritu Santo. These mountain ranges greatly influence weather patterns in Vanuatu by trapping rain from the moisture-bearing south-east winds. The leeward side of the ranges typically experience extended dry seasons and substantially lower annual rainfall in comparison to the windward regions. Low plateaux perched at 100-400 m a.s.l. occur on the larger islands.
Soils in Vanuatu are derived from volcanic rock and ash, coral limestone and sedimentary deposition (Macfarlane and Shelton 1986). Soils of agricultural importance in Vanuatu consist of 4 major types:-
Alluvial soils (entisols)
Agro-ecological zones are determined by rainfall and soil type, and to a lesser extent temperature. The southern and eastern regions and plateaux of most islands are strongly differentiated from western and northern regions by rainfall. A dry season occurs from May to October but its severity and duration varies greatly between climatic zones. The dry season coincides with the cool season and the occurrence of south-east trade winds.
High rainfall regions
High rainfall regions, receiving 1800-4000 mm annual rainfall, occur predominantly on the windward side of the mountain ranges. Dry seasons are generally not severe and span a maximum period of 3 months. Mean monthly day/night temperatures range from 30/23°C in the wet season to 25/19°C in the dry season. The bulk of pasture, root crop and small crop production occurs in these areas.
Low rainfall regions
Regions in the lee of mountain ranges vary in rainfall from 1200-1800 mm annually and can experience severe dry seasons of up to 6 months duration. For example, the White grass region on north-west Tanna and the Tontar on north Malekula receive 1200 and 1400 mm rainfall annually, respectively. These areas can be subjected to annual burning which helps to control woody weed problems.
The free draining calcareous soils of the narrow coastal belt on the southern and eastern regions of most islands are utilised primarily for the production of coconuts. These regions include small, low altitude islands adjoining the larger islands. A sharp rainfall gradient is generally present at the escarpment between the lower rainfall coastal belts and the plateaux. Annual rainfall ranges from 1500-2000 mm and the duration of the dry season is significantly longer than the adjoining plateau regions.
Tanna Middle Bush region
The Tanna White grass region deserves special mention because of its subtropical climate. At latitude 19°30íS and altitude of 400-600 m a.s.l. the region experiences average monthly cool season minima of 11-12°C. Middle Bush receives 3500 mm rainfall annually and is occassionally subjected to acid rain from the Yasur volcano. Subtropical and temperate crops are produced seasonally in Middle Bush.
4. RUMINANT LIVESTOCK PRODUCTION SYSTEMS
Both smallholder and plantation graziers in Vanuatu predominantly utilise free-grazing systems. Tethering of animals occurs only occasionally and stall-feeding is not practised. The feeding system in both sectors is entirely pasture based and no supplements or conserved feeds are used.
Cattle under coconuts
The cattle industry in Vanuatu began in the early 1900ís with the introduction of cattle to control growth of understory vegetation in coconut plantations (Weightman 1989). Today nearly all smallholder and plantation graziers graze at least part of their herds under coconuts. As copra prices continue to decline in real terms, the importance of the cattle in the cattle/coconut farming system has increased. In general, daily liveweight gains of steers grazing under coconuts is below that of animals on open pastures due to the reduced quality of shaded pastures (Macfarlane 1993). Reduction in liveweight gains are exacerbated by dense plantings of coconuts (>150 palms/ha) that occur on some smallholder farms. However, high quality veal is produced by specialist graziers grazing cows and calves under coconuts on Efate and Santo.
Cattle grazing open pastures
The bulk of plantation sector cattle production occurs on open pastures on the islands of Espiritu Santo and Efate. In well managed operations, cattle are grazed at 1.5-3.0 AU/ha, depending on agro-ecological region, and turn-off slaughter weight cattle (280-300kg carcass) at 24-36 months. Over the past 20 years, an increasing number of commercial smallholder graziers have been developing open, improved pastures. The rapid increase in stockyard infrastructures on smallholder farms over the past 10 years has improved stock management. Production per hectare from the best smallholder farms is now equivalent to that from the best plantations.
The plantation sector grazes 58,000 ha, of which 16,000 ha is under coconuts. The pasture resource is 21,000 ha of improved grass pastures, 7,500 ha of naturalized buffalo grass (Stenotaphrum secundatum), 7,000 ha of carpet grass (Axonopus compressus) and T-grass (Paspalum conjugatum), and the balance is partly cleared bush (Macfarlane et al. 1994a). The productivity of the various pasture systems is dependent on edapho-climatic conditions, the presence or absence of a legume component, and the degree of weed invasion. Considerable pasture rehabilitation and development was stimulated by the activities of the recent AusAID Vanuatu Pasture Improvement Project 1988-1993 (Macfarlane et al. 1994b).
Carpet grass and T-grass dominate the native/naturalised pastures of the high rainfall regions in combination with the naturalized legumes Mimosa pudica, Desmodium canum, and Desmodium triflorum. In low rainfall regions, Dicanthium, Bothriochloa and Heteropogon spp. dominate (Evans et al. 1992). Herbaceous and woody weeds seriously reduce the productivity of native pastures throughout Vanuatu (Mullen et al. 1993).
Open pasture systems
The principal improved pasture system in Vanuatu is signal grass (Brachiaria decumbens). Over 16,000 ha of signal grass has been planted, predominantly on expatriate plantations on relatively fertile interior soils in full sun (Evans et al. 1992). Liveweight gains of 0.4 kg/ha/day are common from cattle grazing legume-deficient signal grass and 0.5 kg/ha/day is readily achieved when a significant legume component is included (Macfarlane 1993).
A significant research effort was invested in identifying legumes that would persist in vigorous signal grass swards (Macfarlane et al. 1994a). Puero (Pueraria phaseoloides), Amarillo peanut (Arachis pintoi) and to a lesser exent centro (Centrosema pubescens) and Glenn and Lee joint vetch (Aeschynomene americana) were found to persist well. Some problems with puero dominance of pastures were experienced but this was controlled by short-term heavy grazing once puero dry matter reached a composition of 40% of the pasture.
Other pasture grasses well suited to the high rainfall areas are para grass (Brachiaria mutica), koronivia (Brachiaria humidicola), hamil, green panic and embu (Panicum maximum) (Table 2). Pasture mixtures of signal and Hamil guinea are compatible with twining legumes and have been highly productive.
In low rainfall regions, sabi grass (Urochloa mozambicensis) and Bothriochloa pertusa proved to be valuable grasses in combination with Seca stylo (Stylosanthes scabra), siratro (Macroptylium atropurpureum) and leucaena (Leucaena leucocephala). In the subtropical environment of Middle Bush, Tanna, kikuyu (Pennisetum clandestinum) combines productively with Shaw vigna (Vigna parkeri) and Safari white clover (Trifolium semipilosum).
Stocking rates in Vanuatu range from 1.5 hd/ha in less fertile, lower rainfall sites (<1500 mm/yr) up to 3.0 hd/ha on fertile interior soils with >2200 mm rainfall.
* not sustainable
The preferred pasture species for coconuts planted at 8-10m spacings is buffalo grass. Buffalo grass is extremely tolerant of high grazing pressure and tolerates the lower rainfall coastal environments where coconuts are typically grown (Mullen and Shelton 1996). Where coconuts are mature and light transmission is >70%, grasses such as sabi grass and signal grass can be grown. The alkalinity of the coastal soils reduces the range of suitable companion legumes. Glenn and Lee joint vetch (Aeshynomene americana), Desmanthus virgatus and siratro (Macroptilium atropurpureum) have all proved to be well adapted to coastal coralline pastures but none are as persistent, productive or as high quality as Leucaena leucocephala.
Nitrogen is the most limiting nutrient for pasture production throughout Vanuatu. Regionally, low availability of phosphorus (Erromango, Whitegrass Tanna, south Santo plateaux and Middle Bush Santo, Montmarte Efate), potassium and sulphur (most coastal coralline soils) also limit pasture growth.
Animal production from pastures in Vanuatu is limited nationally by low crude protein levels and regionally by low levels of sodium (interior pastures), copper (Montmarte and coastal pastures) and phosphorus (Evans et al. 1992).
Only 31% of smallholder cattle in Vanuatu have access to drinking water. The effect of this on livestock production varies between agroe-cological zones, but it is likely to be substantial in low rainfall regions.
Weeds pose a serious threat to pasture productivity and sustainability in Vanuatu (Mullen and Banga 1993). Weeds of significance in coastal and interior pastures include Cassia tora, Solanum torvum, Cuphea carthagenensis and Sida acuta. Other weeds which occur in coastal pastures include Psidium guajava, Annona muricata, Stachytarpheta urticifolia and Urena lobata; or in interior pastures include Amaranthus spinosus and Mikania micrantha (Mullen et al. 1993). The combination of correct pasture species and appropriate grazing management will usually be sufficient to prevent serious weed invasion. Grazing management strategies should aim to maintain minimum pasture heights (Table 3). Rehabilitation strategies range from replanting with vigorous improved pasture species to strategic herbicide usage combined with appropriate grazing management (Mullen and Banga 1993).
Large-scale commercial development of livestock production is limited to islands with a reliable marketing infrastructure, and specifically, access to the export abattoirs. Small-scale commercial livestock farms can be developed on other islands where village butcheries, feast markets and cattle barging services are established. On islands where these services are not developed, pasture development for commercial cattle production is unlikely to progress.
There is no recurrent pasture research activity in the Vanuatu Department of Livestock or within the various research institutions. However, a considerable amount of pasture research activity was undertaken during the early 80s through the Vanuatu Pasture Improvement Project with AusAID support. Technical reports, technical bulletins and other materials published form the basis of the current research knowledge (Macfarlane and Shelton 1986, Macfarlane et al. 1994a and 1994b, Evans et al. 1992, Mullen et al. 1993, Mullen and Macfarlane 1998, Macfarlane 1998). The following Department of Livestock personnel have considerable practical knowledge of pasture research and development in Vanuatu:-
Department of Livestock, Ministry of Agriculture, Forestry and Fisheries (1998)
Anon. (1994). Vanuatu National Agricultural Census. Statistics Office, Port Vila Vanuatu. 190 pp.
For further information on forages in Vanuatu contact:
Mr Ben Mullen
Mr David Macfarlane
resource profile was prepared in 1998 by B.F. Mullen and edited by H.M.