Agro-forestry and multi-culture in Asia

Implications for Europe

E.R. Ørskov

Macaulay Institute, Craigiebuckler, ABERDEEN AB 15 8QH, UK

Abstract

In this article agro-forestry is discussed firstly in examples from coconut plantations and oil palm plantations with animal interaction. Reference is also given to regeneration of forests with interaction with complementary crops and crop animal soil interaction in general with different forms of multi-culture.

Introduction

Over many years I have become very impressed by all aspects of multi-culture agriculture including agro forestry and the untapped potential. Multi-culture is sustainable and has many positive effects on soil fertility unlike present practices of mono-culture requiring heavy use of pesticides.

I have come across most of the aspects I refer to in Asia where great pressure of population has given challenges to how best to increase production in a sustainable manner.

Coconut plantations

I first became involved with the challenge of agro-forestry in a research project in Sri Lanka. This was a joint project with the Coconut Research Institute in Lunawila. Large areas of Sri Lanka is covered with coconut owned both by large industries and by small farmers. Coconut trees do not form a dense canopy so it is always possible to grow other plants under the trees. In many instances cattle are seen grazing under the coconut trees. Here it is often the case that the owners of the coconut trees are not the owners of the cattle. Cattle are owned by small poor farmers and usually the owner of the coconut trees lets them graze at no cost. An experiment was set up to graze cattle under the coconut at a high stocking rate. In fact the animals were having much less food than they needed for maximum growth and reproduction.

This can be seen in Table 1 from Pathirana et al. (1996 and Ørskov 2002) The animals were old at calving, calving interval was long and milk yield was low. Supplementing with imported rice straw improved the animals' reproductive performance and if they were also given rice bran performance was further increased so that the calving interval was normal here at 13 months.

Table 1

Effect of grazing and supplementation of female cattle grazing under coconut on age at calving, calving interval and milk yield. Grazing, grazing + rice straw, grazing + rice straw + rice bran

These results may be expected, but the unexpected for me was the beneficial effect on coconut yield given in Table 2.

Table 2

Effect of grazing on annual yield of coconut, soil water holding capacity.

Pathirana et al ., 1995

Just grazing increased coconut yield by about 15%. No wonder the owners of the coconut trees were quite happy for the small farmers' animals to graze under them! This was no doubt due to a rapid turnover of biomass and the effect on soil quality seen here as water holding capacity. Bringing nutrients for the cattle from outside further increased coconut yield not doubt as a result of the N, P and K etc. contained in the feed. This can also be seen in Table 3 showing an increase in N, P and K when feed from outside was added.

Table 3

Effect of grazing and supplementation with rice straw and rice bran on soil, water and coconut leaf composition after 6 years.

Pathirana et al ., 1995

This increase in coconut production by the animal interaction can effectively be seen as an animal product but so often the product is ignored. Since then when I have seen animals grazing under trees or tied to trees I have often asked the question, what is the effect on production from the trees be it mango, coconut, durian or other fruit or on wood production e.g. teak. There is seldom an answer. Maybe this is due to my lack of knowledge but one thing is sure, we need a multidisciplinary system to make good progress here.

Oil Palm plantations

The involvement too of socioeconomy became very apparent to me recently on a visit to an oil palm plantation in Bengkulu province of Sumatra, Indonesia. The Indonesian company owning the plantations employed workers to collect palm fruit bundles from the plantation and carry them to a road passable by trucks. The employers had taken the initiative to give to the workers a Bali cattle (Bos banteng), for pulling a small cart which could hold about 15 to 20 bundles instead of the one carried by the worker. This increased the capacity of the worker to attend to 15 rather than 10ha. The feed for the cattle was plants growing under the trees plus leaves and core from the palm fronds which had to be cut down before a palm bundle could be cut off. At night the cattle were also given some palm sludge from the factory. It soon transpired that there was much more feed than one animal could eat so the farm workers were allowed to take several animals with them during the working day in the plantation. At the moment an average of 6 animals come with each worker in the morning. What is the possible stocking rate under palm oil trees? I was told maybe 2/ha. even with full canopy. If this is so, many millions of cattle could be fed under oil palm trees in the world. These could provide a secure living for many families. Similar effects on oil palm production were observed some years ago recently referred to by Devendra (2004) (see table 4).

Table 4

Effect of mixed cattle and goat grazing on annual yield of fresh fruits in oil-palm plantations in Malaysia. Devendra (2004)

Fresh fruit bunches (metric t. /ha)

*C = cattle: C & G = cattle and goats.

Here there were consistent increases in oil palm yield of some 15 to 20% as a result of grazing with cattle and goats in the plantation, no doubt a result of increasing turnover of biomass and maybe also of soil water holding capacity. The positive effects of agro forestry with animals is not unique to tropical areas. Recent work reported by Sibbald (1999) and Sibbald et al (2001) showed that productivity of sheep grazing under trees was similar and in dry years greater than sheep grazing a similar area in open land. Evidently the growth of the trees was a bonus and soil fertility undoubtedly improved.

Reforestation with the aid of small farmers and their complementary crops

In Indonesia where many forests have been illegally cut the government is trying to re-establish the forests with the aid of nearby small farmers. These farmers are given the right to cultivate and plant complementary crops between the trees, in this case teak and eucalyptus trees, until the full canopy has formed. One may question if the full canopy is necessary for optimal growth and quality of the trees? Less than full canopy could give small farmers continuous access to grazing and other complementary crops and maybe also to better quality trees. Interplanting with leguminous trees and bushes for animal feed could capture N also for the forest trees. The way silvopastoral systems should be developed or perhaps more precisely redeveloped will vary environmentally according to climate, type of trees, type of animals and socioeconomic circumstances. Here what is important is not always the maximum production of trees but the best total production of all the components in the system. An added advantage is that such systems will be much more sustainable than monoculture tree systems and special animal systems. Chickens and pigs after all were forest animals and not designed for large intensive stall fed and battery fed systems. The trees also will accumulate carbon from atmospheric CO 2 and therefore be of help in slowing down climate change. The relentless push to monoculture promoted recently by herbicide resistant GM crops cannot be the solution from environmental and socio-economic points of view.

Advantages of multi-culture

In many tropical areas in developing countries multi-culture has been used for many years particularly in densely populated areas. This involves both combinations of forests with arable crops or grazing animals and a mixture of arable crops. Often three crops are grown together. Very often leguminous crops such as ground nut, Soya bean and peas are grown together with non leguminous crops such as maize, cassava and wheat. The N captured by leguminous plants can be used also by non leguminous plants. These crops are not harvested at the same time. Cassava for instance is generally harvested only once per year while other plants that have a much shorter season can be replanted. Harvesting cannot be done by combine harvesters. However labour is often not a problem and therefore labour saving devices provide no solutions, and often create unemployment and poverty. However these systems are sustainable and help to maintain soil fertility and high yields of crops.

Problems of monoculture

The negative effect of monoculture was recently demonstrated also in rice production. Here herbicides had been recommended for use in the paddy fields. Instead of herbicides ducks were introduced. (Table 5 from Minh et al., 2003).

Table 5:

Integrated system of rice, rice plus duck, rice plus fish, and rice plus fish and duck on net benefit for farmers (Mill.Vietnam Dong/ha)

The ducks ate the weeds and the insects and even increased the yield of the paddy. As the young ducks were also fed at night they essentially brought some fertiliser to the paddy in the form of faeces. Now fish have also been introduced to consume the plankton grown in the paddy fields as a result of the ducks fertilising the paddy. The total income per ha has increased by 50 times. There are so many options to be explored which have many advantages both environmentally and socio-economically and are far superior to the monoculture of crops and specialised animal production.

References:

Devendra, C. (2004) Integrated tree crops � ruminant systems. The potential importance of the oil palm. Outlk. On Agric. 33: 157-166.

Minh, T.N ., L.V., Ly and E.R. Ørskov (2003) Using local ducks to control insects in paddy field and in duck, fish, rice systems and eliminate use of insecticides. SAREC International meeting. Hue, Vietnam 22-26 Marc 2003.

Ørskov E.R., (2002) Trails and Trials in Livestock Research. IFRU Publication, Macaulay Institute, Craigiebuckler, Aberdeen, Scotland.

Pathirana, K.K., Mangalika, U.L.P., Liyanage, M. De S., Ørskov, E.R. (1996) Effect of grazing and supplementation in a coconut plantation on cattle production, coconut yield and soil fertility. Outlook on Agriculture 25, 3, 187-192.

Sibbald, A. R., (1999) Agro forestry principles � sustainable productivity? Scottish Forestry, 53 (1): 18-23.

Sibbald, A.R, Eason, W.R., McAdam, J.H. and Hislop, A.M. (2001) The establishment phase of a silvopastoral network experiment in the UK. Agroforestry Systems, 39: 39-53