CULTIVATION - Tropical Fruits - page 43

with shovels to the tertiary drains after a heavy rain to drain areas where
water accumulates in the fi eld, so that the excess fl ows into the tertiary drains.
Tertiary drains conduct the water to 2.5-4.0-m-deep secondary drains, which
in turn will drain the water into a river or creek or a primary drain that can be
2.5-6.0 m deep.
PLANTATION LAYOUT
A contour or 'Google' map of the farmland is ideal to start layout planning.
The map should ideally include the location of buildings, farm boundaries,
roads, fences, irrigation water supply and drainage ditches. Decisions are then
made on the direction and length of the tree rows, the number of plants, the
need for additional interior roads for transporting materials or products to
and from the fi eld, and location of additional structures such as storage and
machinery sheds and packing facilities.
The length of the rows will depend on the type of soil and irrigation; if
irrigation is by furrows or basin, rows that are about 60-80 m long in light
soils and 120-180 m in heavy soils would be a starting point. Rows that are
too short are not convenient for ei cient machinery movement. The direction
of the rows should take into account the water movement from both irrigation
and runof .
Using the layout map the easiest way to start in the fi eld is to confi rm that
the direction chosen for the tree rows on the layout map is the best and make
appropriate corrections in the fi eld. Use a long string or rope stretched to follow
the direction chosen and then stake each end. These stakes serve to establish
a 90° angle at each end to start the geometric layout pattern. At each of the
ends use a measuring tape with the 0 m mark at the stake and mark the point
on the rope 3 m from the stake, then mark another point with a stake 4 m in
a perpendicular direction to the rope, adjust the position of this stake so it is 4
m from the end stake and 5 m from the 3 m mark on the rope. The 5 m line is
the hypotenuse of your triangle and a 90° angle is formed at the stake. At the
other end of the rope repeat the same procedure, so you have two parallel lines.
Measure on both parallel lines an equal distance to confi rm that the distance
between these two points is the same as the distance between the fi rst two
stakes. If the same, then you have parallel lines, if not you will need to recheck
the two triangles so that a square or rectangle is formed. Then all four corners
are staked and new stakes are put in or the spots marked with gypsum or lime
at the distances the trees or rows will be and repeat on the other side. Then a
rope or wire is pulled between the matching stakes of the opposite sides and at
the perpendicular lines the same is done. Where the ropes or wires cross a stake
or a lime mark is left, which will indicate the location to dig a planting hole.
Orchards are usually planted following geometrical arrangements (Avilán
et al. , 1989), depending on the land condition, the species, variety, plant