Agriculture Reference
In-Depth Information
Weeds in some areas can be very dii cult to control. Areas heavily infested
with aggressive and persistent weeds like nut sedge (
Cyperus
spp.), Johnson
grass (
Sorghum halepensis
), Bermuda grass (
Cynodon dactylon
), star grass
(
Cynodon nlemfuensis
) and others are best avoided. They can be eliminated but
it will take time, ef ort and money.
Mountainous land
Fruit orchards are commonly located on fairly fl at land, as steep and
mountainous land is more expensive to prepare and carry out fi eld
management. The advantage of mountainous land is that it is often cheaper
and usually has not been used for any fruit crops previously and is more
likely to be free of many parasites, weeds and chemical residues common
in other areas. Mountain soils need to have good soil texture and depth to
allow for good root establishment and growth. Erosion can be a problem on
steep hillsides, so care has to be taken not to eliminate the low vegetation
and to plant on the contour to minimize erosion. Terraces built along the
contours often have deep soils, though these terraces are expensive to build
and maintain. Individual terraces for each tree are also used. Drainage will
normally not be a problem under these conditions.
Irrigation of steep hillsides can be dii cult, especially in the arid tropics
or tropics with a long dry season. An expensive irrigation infrastructure is
needed, which includes tanks to store water at the highest elevation and
pumps to fi ll the tanks. In older orchards, contour irrigation systems are seen,
with newer orchards using drip irrigation and micro-sprinklers. The fl exibility
of drip and sprinkler systems is that they are not limited to fl at land and can be
used very easily on steep hillsides and on stony or poorer soils. Once the water
is pumped to the tank at the highest part of the orchard, gravity can be used
with pressure compensation drippers. Pressure-compensated drippers emit
equal amounts of liquid along the system, with a range of supply pressure.
LAND PREPARATION
In virgin areas, land preparation for fruit crops can be as simple as just
removing the trees and other vegetation before digging a planting hole. This
approach was used by the companies for banana plantations in Central
America. In mountainous areas, land preparation is normally by hand or with
small motorized equipment; larger machinery normally cannot be used. Large
trees and bushes are removed with the low vegetation left, and individual
holes are dug for each tree. This could include making a small terrace with the
planting hole at the centre.
