9. TREE PROPAGATION METHOD

9.5 On-farm nurseries

Suitable species

Some popular tree species are best propagated in on-farm nurseries. Species with small seeds, e.g. Eucalyptus, Grevillea and Cypress, are difficult to sow directly with good results and thus are best raised in small on-farm nurseries. The seeds of other species may be scarce and therefore optimum use must be made of the little seed that is available. This also calls for raising seedlings in nurseries.

Timing and availability of water

Seeds should be sown in time to obtain seedlings of a suitable size for planting out at the beginning of the rains. Fast-growing species need less than three months from sowing to attaining a suitable size for planting, whereas more slow-growing ones will require 4-6 months. Thus the nursery will need to be in operation during the dry season, and all nurseries of any size should therefore be located near a good water source.

Figure 9.5 Watering a home tree nursery

If there is no water source on farm, then it is advisable to have only a very small nursery with 30-40 seedlings which can be watered using household waste water. Carrying water long distances for tree nurseries should always be avoided; it is easier to carry seedlings once to the desired planting site than to transport water for the seedlings throughout the dry season.

Establishment

Small nurseries can easily be established and managed by the farmer with the help of his family. The number of seedlings raised can vary from very few to as many as may be needed on the farm or can be sold in the area. Ordinary farm tools are normally sufficient for managing such a nursery, e.g. a jembe, a panga and a tin with punched holes for watering.

Seedlings can either be raised in containers or without containers. Those grown in containers normally have a better chance of becoming quickly established and surviving than seedlings raised without containers. If polythene tubes are not available, old tins, milk packets or containers made from banana fibre can do as well. If a farmer prefers to raise seedlings without containers, a small nursery bed, approximately 60 x 100 cm and 20-30 cm deep can be made in a well-protected area of the farm. Banana stems, poles, boards or bricks can be used for a frame for the bed, which can be secured by pegs, stones or soil.

Figure 9.6 A farmer sowing seed

Fill the frame with good fertile topsoil, not too clayey nor too sandy. Firm the soil lightly. Sow seeds in furrows which are 10 cm apart and at a depth corresponding to twice the seed diameter. Cover seed with soil and firm lightly after sowing. Cover the seedbed with leaves or grass to conserve moisture, and water carefully. Remove the cover when the seedling shoots appear.

Management

The seedlings need watering, weeding, root pruning and protection against sun and animals. Construct a light shelter with sticks, about 75 cm high, and a roof of grass, straw or leaves to shade the seedlings. Reinforce the sides with a rough fence of thorny branches or sticks to protect the nursery from browsing and trampling. The seedlings should be watered twice a day, morning and evening, when the sun is not too hot. A tin with punched holes can be used for sprinkling the water. Weed regularly and thin the seedlings to an in-row spacing of 5 cm.

Figure 9.7 Watering seedlings

Root pruning helps the seedlings grow stronger and to build up a balanced root system. The first pruning is done when the seedlings are 5 cm high. Root pruning should be done in the early morning or in the evening. Remove pegs or stones from around the frame and water the nursery bed thoroughly. Use a sharp panga and run it underneath the nursery bed to prune the taproots. Then prune the side roots by running the panga carefully between the rows of seedlings. Put back the supports around the frame after pruning.

Newly pruned seedlings are sensitive for the first few days and need careful watering and shade. Root pruning should be done at least once a month, and more often for fast-growing species. Before outplanting, the seedlings should be hardened off during the last month. This involves gradually removing shade until the seedlings are exposed to full sunlight, reducing the watering to once a day and gradually increasing root pruning to once a week.

Figure 9.8  Root pruning

Planting

Water the nursery bed and remove the frame. Use a sharp panga to cut up the nursery bed into one soil block for each seedling. Carry the seedlings carefully to the planting site where holes have been prepared in advance. Place the soil block in the hole and firm soil around it. Water the seedling immediately after planting if it is not raining. Weed and protect the seedling just like any other planted tree.

Where are on-farm nurseries feasible?

Very small on-farm nurseries using household waste water can be established and managed both in high-potential areas and in ASAL areas. Larger on-farm nurseries which depend on a permanent water source cannot so easily be run in ASAL areas due to the scarcity of water sources there.

Figure 9.9Young seedlings need shading

Footnote__________

Section 9.5 is partly based on Fahlstrom, K. 1991. Home Nurseries. Extension Leaflet. Nairobi: Ministry of Agriculture, SWCB.