Agriculture Reference
In-Depth Information
suitable site is found, land is cleared, and suitable tree stock is planted. The trees are
weeded and protected from insect and animal damage. This is often a 5- to 10-year
commitment before trees bear nuts in sufficient quantities to be economical.
6.8.5 Long-Term Care
Nut trees may produce nuts for long periods of time, up to 100 years (up 250 years for
black walnuts!). For high productivity, the plantings must be cared for by keeping the
area under the trees clean and free of debris; see Figures 6.27 and 6.28. Some nut trees
may benefit from pruning, although some may not. It may also be necessary to spray the
trees from time to time to protect them from insects.
6.8.6 Protection
There are three approaches to protection of nut trees, although in general they need
less protection than fruit trees. Roots from varieties resistant to various pests can be
used as the graft stock for the desired varieties. This then protects the tree from soil-
borne diseases. Physical barriers such as wrapping the trunk of trees can protect them
from damage by animals such as deer. Trees can be sprayed with pesticides to control
insects and herbicides between the trees to control weeds.
6.8.7 Harvest and Postharvest
When ripe, many nuts fall naturally from the tree and can simply be picked up from the
ground. This may be a satisfactory procedure for situations where the nuts are intended
for family or local use. For commercial production, trees may be mechanically shaken
(Fig. 6.27) to remove nuts that then can be swept up (Fig. 6.28) and collected for
processing. Care must be taken not to damage the tree while carrying out this operation.
In some cases the nuts must be harvested by hand because they do not fall off the
tree naturally or they are highly perishable and must be handled carefully. This would
be the case with chestnuts.
Each type of nut is unique, and several, such as the cashew and chestnut, have very
unusual characteristics. The cashew nut forms on the end of a fruit called an “apple.” In
some places the apple is used as food; in others it is discarded. The nut is encased in a
shell that contains a liquid that can produce skin blisters and swelling. This liquid must
be carefully removed before the nut can be used as food. The chestnut has a spiky cov-
ering that breaks open to release the nut when ripe. In many cases the nut itself is sur-
rounded by a fleshy outer covering, as with black walnuts, that is removed and
discarded before the nut is cleaned for in-the-shell sale. The shell is removed when
the nut is eaten or processed for use in food production.
Handling after harvest will depend on the nut and its particular characteristics. In
some cases the soft outer vegetative covering may need to be removed as in the case of
cashews and black walnuts (the outer vegetative portion of cashews is edible and the
outer portion of black walnuts can be eaten by domesticated and wild animals). In
