Overstory #37 - Trees/Livestock Examples

Editor's Note

This is the third in our series on animals in agroforestry. The first (#35) covered the advantages and disadvantages of integrating animals with agriculture and forestry. The second (#36) introduced the practice of silvopasture, integrating livestock in forestry system. In this edition of The Overstory, special guest authors Dr. Ross Gutteridge and Dr. Max Shelton summarize examples of several important agroforestry systems which incorporate animals Productivity of Animals in Agroforestry Systems.

Plantation crop systems

The principal plantation crops where integration of livestock is possible are rubber, oil palm and coconuts. In the past, most attention has focused on the integration of cattle with coconuts and this system has the greatest potential for further development. The unique quality of coconuts, compared to most other plantation crops, is the relatively constant and bright light environment over the life of the crop (60-80 years). Consequently, understorey pastures can be grazed on a semi-permanent basis. Liveweight gain potential can be quite high and is influenced by a number of factors but particularly light level. Improvement is possible through the use of shade-tolerant pasture species.

There is increasing interest in the grazing of sheep in rubber and oil palm plantations. In Malaysia, the productivity of sheep under rubber has been extensively investigated. Experiments showed that productivity was moderate under young rubber (2-5 years) provided palatable leguminous cover crops were grazed, but low under mature rubber where light levels had fallen to 20% transmission of light. There is potential to increase productivity by using shade-tolerant forage species and by altering the conventional rubber planting system to a hedgerow system.

Forestry systems

Successful forest grazing systems based on Pinus radiata and sheep have been developed for the temperate regions of southern Australia and New Zealand. Sheep are preferred because they are less inclined to browse the trees than cattle. Stocking rates vary between 12 and 25 animals/ha in the early stages of tree development, but need to be reduced by at least 50% by year 10.

In the tropics, forest grazing systems have been less successful. In the Solomon Islands, pastures and cattle under Eucalyptus deglupta plantations at densities of 130 stems/ha could not be sustained in the long term. In a young plantation (trees 23 years old), a stocking rate of 2.5 beasts/ha, giving liveweight gains of 0.45 kg/hd/day was achieved; however, by year 7 with almost complete tree canopy cover, stocking rates had to be reduced to less than 1 beast/ha, producing only 0.25 kg/hd/day liveweight. Substantial damage to the trees due to bark stripping by the cattle also occurred.

Animal production in forest plantation is therefore transient unless the trees are widely spaced, permitting ample light penetration to the pasture.

Horticultural systems

A number of other tree crop species such as mangoes, kapok, tamarind, cocoa and cashews have some potential for integration with livestock as they are usually planted on a wide spacing (10 x 10 m or 8 x 8 m) which promotes food light penetration especially in young crops.

The animal production potential from these systems, although not well documented, would not be high because of the precautions necessary to prevent damage to the often palatable leaves of the crop and the low light profile when the trees reach maturity.

A specialized agrosilvopastoral horticultural system in Bali is vanilla production under coconuts—the vanilla orchid is supported and shaded by the tree legumes Gliricidia sepium or Erythrina sp. The shade level is regulated by lopping the branches of shade trees which are fed to livestock.

Livestock and Alley farming

The inclusion of livestock into alley farming systems necessitates that farmers change their tree management and foliage use practices. The daily demands of animals for feed require tree pruning at times unnecessary for cropping. Thus in alley farming, prunings taken at or near crop planting are used as mulch for the crop while all or part of later prunings can be used for animal feed.

At Ibadan in Nigeria, Reynolds and Atta-Krah suggested that the surplus foliage from 1 ha of Leucaena leucocephala and Gliricidia sepium from alley farming could provide half the daily fodder requirements for 29 goats. In the dry season fallow period, livestock can be allowed direct access to the cropping area to graze crop residues and browse the trees. In Malawi, a 0.25 ha leucaena alley farm produced enough leaf material to feed three dairy cattle 3 kg/DM/hd/day during the dry season.

In lowland humid regions of the tropics where farm size is often small, the amount of forage generated from alley farming is very low. However, in semi-arid regions, the additional forage from both prunings and crop residues may be the major incentive attracting farmers to use the alley farming technique.

Trees in cropping systems

In the more intensive agricultural areas of Asia and Africa where land is scarce and livestock are raised in small numbers by smallholder farmers, forage tree legumes are planted as 'fodder banks' along border or fence lines, and on rice paddy bunds or in home gardens. Foliage from these trees is usually harvested under a 'cut-and-carry' system and is a principal source of high quality fodder to supplement low quality fodder such as crop residues. In China, the leaf of the deciduous tree Paulownia, grown over an area of 1.8 million ha of cropping land, is collected in autumn and fed to cattle, sheep and pigs.

In parts of Africa, the incorporation of tree legumes in cropping areas has been described as 'the bedrock of traditional agroforestry systems in Africa'. The trees are occasionally lopped for feed and are grazed in the dry season. Animal productivity is generally low. In the Batangas region of the Philippines, a 2ha area of Leucaena leucocephala grown in association with the fruit tree Anonna squamosa was able to supply the forage requirements of 20 growing cattle over a 6-month period.

Three strata systems

The three strata forage system is an integrated agroforestry practice developed in Bali, Indonesia. It enhances crop and livestock production through the provision of forage, to supplement crop residues from the cropping area, from a combination of pastures, shrubs and trees. The system comprises three tiers or strata of forage grown as borders in an upland cropping system.

The system aims to produce a constant high quality feed supply throughout the year. The first stratum of herbaceous grasses and legumes supplies forage from the early wet to the early dry season; the second stratum of tree legumes provides forage for the early dry to the mid-dry season while the third stratum of taller trees covers the period mid-dry to early wet.

Results indicated that the three strata system produced 90% more feed and carried a 29% higher stocking rate in the wet season and 46°%, higher stocking in the dry season compared to the traditional system. The growth rate of animals from both systems was similar. Although crop production was reduced slightly in the tree strata system, an economic analysis of both systems indicated that profitability was higher and risk more widely spread in the three strata system.

This system would appear to have wide applicability outside the Bukit Peninsula where it was tested. The environmental conditions there (1000 mm rainfall, long dry season 7-8 months) are similar to many other regions of the semi-arid tropics.

Summary and Conclusions

There is substantial potential for animal production in animal-based agroforestry systems and a number have been designed specifically to improve or enhance animal productivity. High levels of production are only possible through the use of high quality fodder-tree legumes when livestock production is the major economic activity. Further evaluation of the existing tree legume varieties will broaden the resource base available and enable the expansion of these systems into a wider range of environments.

The animal production potential of forest and plantation crop grazing systems is relatively low and improvements in these systems will come largely from the identification and selection of herbaceous forage species tolerant of lower sunlight conditions. Improvement is also possible through changes in plantation management practices such as tree spacing and pruning regimes.

In all systems the service role of the trees in providing shade and shelter must be taken into account as this aspect is often undervalued in assessing the productivity of agroforestry systems. This article was adapted from the original Animal Production Potential of Agroforestry Systems by Dr. Ross Gutteridge and Dr. Max Shelton, from ACIAR Proceedings entitled "Agroforestry and Animal Production for Human Welfare" editors J.W. Copland, A. Djajanegra and M.Sabrani Proceedings No.55 1994. ACIAR Canberra. Kind permission to reprint was granted by the Australian Centre for International Agricultural Research (ACIAR)

References

FACT Net, 1998. Nitrogen Fixing Trees for Fodder Production - A Field Manual, Forest, Farm, and Community Tree Network (FACT Net), Winrock International, 38 Winrock Drive, Morrilton, Arkansas 72110-9370 USA Tel: 501-727-5435, Fax: 501-727-5417, Email: Web:

Ross Gutteridge and Max Shelton, Eds, 1994. Forage Tree Legumes in Tropical Agriculture. CAB International, Oxon, UK.

Related Editions to The Overstory

• The Overstory #50--Animal Tractor Systems
• The Overstory #36--Silvopasture
• The Overstory #35--Animals in Agroforestry