Drip Irrigation Systems
The major factors that determine the necessity of irrigation are the selection of crops and an appropriate
cropping system. Obviously, not all crops (and not even all varieties of the same crop) require the same
amount of water, and not all need water over the same period of time.
Some crops are very resistant to drought while others are highly susceptible. Deep rooting crops can extract
water from deeper layers of soil and hence they are less sensitive to temporary droughts.
With the help of irrigation, many crops can nowadays be grown outside their typical agro-climatic region.
This may cause not only the above mentioned negative impacts, but also some advantages. It may make it
possible to cultivate land which would otherwise be unsuitable for agriculture without irrigation. Or the
cultivation of sensitive crops can be shifted into areas with less pest or disease pressure.
There are irrigation systems of higher or lower efficiency and with more or less negative impact. If irrigation
is necessary, organic farmers should carefully select a system, which is does not overexploit the water
source, does not harm the soil and has no negative impact on plant health.
One promising option are drip irrigation systems. From a central tank, water is distributed through thin
perforated pipes directly to the single crop plants. There is a continuous but very light flow of water, thus
allowing sufficient time to infiltrate in the root zone of the crops. In this way, a minimum of water is lost and
the soil is not negatively affected.