Agriculture Reference
In-Depth Information
Transplanting distance depends upon the species of Annona . The
periodically pruned small sweetsop can be spaced at 3.7 m × 4.6 m. In dry
areas with less luxuriant growth, closer within-row spacing than 3.7 m can be
considered. Closer spacing would increase humidity and benefi t the longevity
of stigma receptivity. For machine operations, wider spacing of 5.0-5.5 m ×
6.0-6.5 m can be used.
Cherimoya can be planted at 5 m × 6 m within and between rows, with
appropriate pruning practices. Row spacing of 5-10 m and between rows
7-12 m are recommended for atemoya in Australia, depending on cultivar,
rootstock and pruning to an open goblet. Narrower spacing is used for
'African Pride' on A. squamosa rootstock, and the widest spacing is for 'Pink's
Mammoth' on A. cherimola . In Florida, narrow plant spacing of 4-6 m and
row spacing of 6-7 m are used (Campbell, 1985). A triangular layout is
recommended whatever planting distance is selected, with the rows running
north-south to avoid shading. In Chile, narrow spacing (4 m × 2 m) has been
tried for cherimoyas, and there are some commercial plantings that use 5 m ×
1.5 m (Gardiazabal and Rosenberg, 1993). Some experimental trellis plantings
also exist.
Irrigation practices
The Annonas are grown in many areas without irrigation when rainfall is
well distributed. Except for pond apple ( A. glabra ), most Annonas can stand
periods of drought and prefer rather dry conditions. There must be adequate
soil moisture to encourage vegetative growth, since fl owering occurs on new
growth. Bearing atemoya trees may need up to 1440 l/tree every 4 weeks
during the low-growth phase and from 500 to 750 l/tree every 3-5 days
during fl owering, fruit set and fruit growth (Sanewski, 1991). Reducing
irrigation in late winter to force atemoya and cherimoya trees into dormancy
for 1-2 months in spring is recommended in Australia and California,
respectively. The amount and frequency of irrigation must be determined by
experience in any particular location and soil type. Water stress should be
prevented during fl owering, fruit set and fruit development, as fruits are more
sensitive than leaves to water stress (Fig. 6.7).
High soil moisture to increase humidity during the fl owering season
may prolong stigma receptivity and fruit set and growth. The use of low-
rise sprinklers under the tree canopy during fl owering increases the canopy
humidity. The stomata of Annona respond to RH, not water stress, and will
continue to lose water if the humidity is greater than 80%, making it crucial
to maintain soil moisture content (Marler et al. , 1994).
 
Search WWH ::




Custom Search