Annona Species Monograph.pdf - Crops for the Future

Chapter 10. Agronomy
method can, supposedly, save time and money with nursery management of
the rootstock, its cost-benefit ratio is likely to be very high, considering that
grafting operations in the field have very low success, obliging the grower to
replant the orchard later.
10.2.5 Transplanting and spacing
In general, annona plants are ready for transplanting into the field or for use
as rootstocks when they are about 8 to 15 months old, have attained a height
from 50 to 100 cm and have at least 4 to 6 mature leaves. Before
transplanting, many growers cut the leaves in half, to reduce transpiration,
and cut the tip of the main root, apparently to induce production of more
lateral roots. Both are empirically developed practices and have not been
validated by research.
The plastic nursery bags should be removed and the plant's collar placed at
the ground level or, at the most, a few centimetres above the ground level if a
planting depression is used to facilitate watering. The young plants should be
irrigated as soon as possible after transplanting and they should be supported
to avoid wind damage. Also, a mulch should be provided to avoid soil
dryness around the newly transplanted materials. Although thick black plastic
can be used to cover the area under the canopy of the new annona tree to
avoid water loss through evaporation, dried grass or rice husks are much
more practical materials; they are also biodegradable and avoid
environmental problems, as well as being cheaper and easily found in the
field.
Current field spacing ranges greatly among commercial orchards, from 6 x 4
m to 8 x 6 m for cherimoya (George and Nissen, 1992), 4 x 4 m to 8 x 8 m
for soursop (Torres and Sánchez, 1992; Pinto and Silva, 1996; Pinto and
Ramos, 1997), 3 x 3 m to 5 x 5 m for sugar apple (Coronel, 1994) or 4 x 4 m
on poor soil and 5 x 7 m on good soil (Singh, 1992). There is no
experimental information on the recommended spacing of custard apple, this
is certainly due to the absence of commercial orchards. For wild soursop, 5 x
5 m is recommended (FAO, 1988).
Some authors (Campbell and Phillips, 1983; Nakasone and Paull, 1998)
comment that annona spacing also depends upon the rootstock and pruning
management. In Florida, narrow plant (4 - 6 m) and row spacing (6 - 7 m) is
used for cherimoya; the rows run North-South in a triangular layout,
whatever the planting distance used. Narrower spacing is also used for
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