The marked trend towards keeping more ruminants for increased meat production in Southeast Asia requires considerable expansion of the forage supply from sources that are currently under-utilised. The land used for plantation crops is one source that has obvious potential for integration with forages and livestock. Coconut, rubber and oil palm plantations already supply some naturally occurring forages, and this land could support increased forage production.
An earlier ACIAR project on this theme (8560), led by researchers in the Department of Agriculture at the University of Queensland, identified a number of forage species that outyielded the best local forages by several hundred per cent. In the course of the project, these species were grown in small, rigorously cut plots over a 2-year period. While the new species have the potential to double the level of animal production in plantation crops, testing in key plantation systems under realistic management practices remains to be done. A review at the end of project 8560 recommended that the same collaborative team undertake a new project to test the most promising species in actual farming systems.
The replacement project is aimed at integrating selected forage germplasm with tree plantations for improved and sustainable ruminant production. A series of field experiments will target three farming systems:
. tethered cattle intensively grazing areas under coconut on smallholder farms in Bali;
. herded cattle exerting more lenient grazing pressure on small and medium-sized coconut farms in North Sulawesi; and
. sheep grazing on smallholder rubber plantations in Malaysia using either conventional or alternative (e.g. ‘hedgerow’) rubber-planting systems.
The selected forages will be tested, in grass-legume combinations likely to fit grazing requirements of the target farming systems, in three ways:
. a small number of best-bet forage combinations will be evaluated under defoliation by grazing to simulate actual farm managment practices in a formal experiment with small plots;
. the same grass-legume mixtures will be established under smallholder plantations to test their performance under farm conditions; and
. productivity of animals grazing one or two best-bet forage combinations in large paddocks will be compared with that of animals grazing local pasture.
The grazing trial will also provide information on the persistence, weed invasion and botanical composition of these best-bet mixtures, and the effect grazing these mixtures has on tree growth. In Malaysia, animal production will be measured in conventionally planted rubber and also in the new hedgerow rubber planting system. The latter system has special potential for increased animal production with minimal reduction in rubber production because it allows more light on the pasture for a longer period.
A smaller Australian research component will support the overseas research and develop basic principles to ensure that the results can be applied to other countries and other plantation crops. The project output (a model to estimate potential forage productivity) will be integrated into a simple decision-support system that will estimate potential animal production under different plantation systems, the expected effect on the plantation crop yield, and weeding costs.
The identification of productive, persistent and farmer-acceptable forage mixtures for coconut and rubber plantations will lead to increased animal production in the developing countries, with reduced reliance on meat imports and a reduction in the use of herbicides. The advantages of dual land use include: better use of scarce land resources; increased and diversified income; soil stabilisation; potential for increased plantation crop yield through better weed control, nutrient cycling and nitrogen accretion; and better weed-control management.
Information gained will be valuable in planning, managing and assessing future agroforestry systems. Of particular benefit to Australia will be the prediction of potential forage growth under plantations, the identification of suitable forages, and the development of management guidelines for forages in tree plantations.