Tree spacing is affected by factors such as the species of citrus concerned, the cultivar, the type of rootstock, the environment, the size of the orchard, and the manage-ment practices which the grower will be using. For example, if he will be using machinery, he must leave enough space between the rows for the machines to pass when the trees are mature (Fig. 1).
Small or dwarf citrus species should be planted at a higher density.
Tall citrus trees, and those with rapid growth, should be more widely spaced.
Planned Close Spacing
For maximum benefit per unit area, spacing can be as close as possible when the trees are planted. Later, as the trees grow in size, they can be thinned.
Most orchards on level ground can be planted in a square or a rectangle. For close spacing or planned close spacing plantings, a quincunx system can be used. (In a quincunx arrangement, four trees are planted at each corner of a square, with a fifth tree in the middle). In orchards on sloping land, trees should be planted along the contours.
Time of Planting
The optimum time for planting citrus trees varies according to the species. It also depends on the condition of the roots and shoots of the seedling. Transplanting the seedlings out in the field is best done at the beginning of the wet season. Growers should avoid transplanting seedlings during hot summer weather.
Handling the Seedlings
Seedlings with bare roots should be planted out as soon as possible after they have been removed from the soil or growing medium. Seedlings grown in containers have generally become root-bound by the time they are ready for transplanting.
Roots which are severely bent and twisted should be pruned before the tree is transplanted. Overcrowded leaves and shoots should also be pruned.
In orchards on sloping land, or in orchards where the trees are widely spaced, seedlings are usually planted by digging a hole for each seedling (Fig. 2). If the orchard is to have closely planted trees, it is preferable to dig a furrow along which the row of seedlings will be planted. Covering the soil around the planting hole with mulch will help conserve soil moisture and keep down weeds (Fig. 3, Fig. 4).
An orchard planted at a high density can make a good profit in the early years after planting. However, after the trees become mature, they are too crowded and ventilation is poor. This increases the relative humidity, and the incidence of pests and diseases. At this stage, closely planted trees should be thinned or trimmed, to open up space between them.
Index of Images
Figure 1 Newly Planted Citrus Orchard
Figure 2 Planting Holes for New Orchard
Figure 3 Seedling with Straw Mulch to Conserve Soil Moisture and Keep down Weeds
Figure 4 Diagram of Planting Hole for Young Seedling
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