Even sprinkling longer and
less frequently helps accomplish that. Half the reason that drip
systems are more efficient is that the surface isn't dampened and
virtually all water goes deep into the earth. The other half is that
they avoiding evaporation that occurs while water sprays through the
air between the nozzle and the soil. Sprinkling at night or early in
the morning, when there is little or no wind, prevents almost all of
this type of loss.
To use drip irrigation it is not necessary to invest in pipes,
emitters, filters, pressure regulators, and so forth. I've already
explained how recycled plastic buckets or other large containers can
be improvised into very effective drip emitters. Besides, drip tube
systems are not trouble free: having the beds covered with fragile
pipes makes hoeing dicey, while every emitter must be periodically
checked against blockage.
When using any type of drip system it is especially important to
relate the amount of water applied to the depth of the soil to the
crops, root development. There's no sense adding more water than the
earth can hold. Calculating the optimum amount of water to apply
from a drip system requires applying substantial, practical
intelligence to evaluating the following factors: soil water-holding
capacity and accessible depth; how deep the root systems have
developed; how broadly the water spreads out below each emitter
(dispersion); rate of loss due to transpiration.
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