7.4 Intercropping for tree planting

It is also possible to intercrop only for a few years while a woodlot or tree plantation is being established. This is known as the Taungya system. The trees benefit from the soil preparation and weeding for the agricultural crop. The farmer will protect both his food crops and the seedlings. As a result, the trees survive much better and grow much faster. This form of intercropping can be practised by individual farmers or by landless cultivators that lease the land for two or three years. In the latter case it is important that the responsibilities and rights of the farmer and the landowner are clearly explained and that a contract is drawn up. The lease usually specifies who is responsible for planting and caring for the tree seedlings. Each cultivator is allocated about 0.5 to 1.5 ha of land. Leasing procedures are often complicated by the fact that the local population distrusts the forest service or the state, because of bad experiences in the past (such as unclear ownership or expropriation without compensation).

After ground preparation food crops are planted. Normally annual crops are cultivated such as beans, maize or sweet potatoes. A particularly good combination are sweet potatoes cultivated on ridges, as shown in the figure opposite. Sweet potatoes can grow on relatively poor sites, they are quite shade-tolerant and the ridges provide excellent soil and water conservation. Perennial crops like bananas, papaya and cocoa can also be grown. Tree seedlings are planted at the same time, or one or two years after the food crop. Large tree seedlings should be used because they are sturdy and easily seen. Spacing between the rows of trees should be wider than for a normal plantation to delay the time when the canopy of leaves closes over and shades the food crop.

The raising of food crops continues until the shade from the trees prevents satisfactory growth. This may last up to four to five years depending on tree growth, initial spacing and the kind of food crops grown. The area is abandoned by the farmer when it is no longer suitable for growing food. Normally, he will already be working in a new area nearby. The farmer may also work several small areas at the same tune, clearing a new one each year.

Intercropping for tree planting

On own land

or leased land

Example for intercropping with sweet potatoes and trees

year 1

year 2

year 3