Operating Drip Systems
A drip system is usually permanent. When remaining in place during more than one season, a system is considered permanent. With availability of right skills the system can be automated.
Water can be applied frequently (every day if required) with drip irrigation and this provides very favorable conditions for crop growth. However, if crops are used to being watered each day they may only develop shallow roots and If the system breaks down, the crop may begin to suffer very quickly.
Unlike surface and sprinkler irrigation, drip irrigation only wets part of the soil root zone. This may be as, low as 30% of the volume of soil wetted by the other methods. The wetting patterns which develop from dripping water onto the soil depend on discharge and soil type. Figure 64 shows the effect of changes in discharge on two different soil types, namely sand and clay.
Figure Wetting patterns for sand and clay soils with high and low discharge rates (SAND)
Figure Wetting patterns for sand and clay soils with high and low discharge rates (CLAY)
Although only part of the root zone is wetted it is still important to meet the full water needs of the crop. It is sometimes thought that drip irrigation saves water by reducing the amount used by the crop. This is not true. Crop water use is not changed by the method of applying water. Crops just require the right amount for good growth.
The water savings made using drip irrigation is due to the reductions in deep percolation, in surface runoff and in evaporation from the soil. These savings, it must be remembered, depend as much on the user of the equipment as on the equipment itself.
Drip irrigation is another way of applying water. It is best suited to areas land is steeply sloping where water or labor are expensive, or where high value crops require frequent water application.