The ManicaPost
It is evident that climate change has a negative impact on agriculture. It has manifested in the form of change of the rainfall patterns with mid-season droughts common across the country. Though the year 2014 saw some above average rainfall and some farmers managed to produce high yields, some areas remained affected.
It clearly remains uncertain and unlikely that the country is going to receive the good rains in the following seasons. Crop failure will be the end result in areas which do not receive enough rainfall. Those crops grown outside the rainy season are affected because of limited water supplies.
Dam water levels will be below capacity to sustain irrigation, reduced river flow and even very low water tables for those who would want to use underground water. All this will hinder agricultural activities due to limited availability of irrigation water.
Another thing that thwarts progress in agricultural activities is the busy schedule of farmers that limits time spend in the field. With the limited financial resources, smallholder farmers cannot manage to hire extra labour to do the irrigation using conventional or traditional method such as cans, hosepipe or overhead irrigation. As a result, even if the water is available, farmers will not realise good harvests. Faced with these and other challenges related to irrigation an alternative would be the use of drip irrigation.
Drip irrigation is a system that distributes water directly to the soil at a very low rate (in drops) from a system tank into small diameter plastic tubing fitted with outlets called emitters or drippers. The system uses gravitational force to move the water from the tank down to the intended point (For large areas and for systems with tanks on the ground the pressure might need to be boosted by pumps). Drip irrigation is highly efficient because the water soaks into the soil before it can evaporate or run off. The water is also applied close to the plant root zone providing a high moisture level in the soil in which plants can thrive.
A properly designed and installed drip irrigation system can achieve up to 90% irrigation efficiency. This can significantly reduce water use. Drip irrigation also allows for: Matching the water application rate to each plant, applying water directly to the root zone of the plant, eliminating runoff, over-pray and evaporation, reduction of disease problems associated with moisture on some plants (especially fungal diseases which thrive in damp conditions)
The following advantages are associated with drip irrigation according to the Drip Irrigation Handbook by Tom Bressan.
· For many gardeners/farmers, water conservation is the main reason for installing a drip system. When watering the garden, the purpose is to water plants rather than soil. Drip irrigation gives the ability to put water exactly where it’s needed and keep paths and areas between plants dry. This reduces both waste and weeding.
A drip system produces healthy, fast-growing plants. In fact, improved crop yields were the primary force behind the development of drip irrigation for agriculture.
In traditional watering methods there is an extreme fluctuation in the water content, temperature, and aeration of the soil, resulting in plant stress. Drip watering keeps the moisture content of soil relatively constant and ensures that oxygen remains available to the root system.
Allows precise regulation of the amount of water used during irrigation so that nearly all of it remains in the root zone. Water lost to evaporation is negligible compared to overhead watering.
Traditional watering methods deliver water faster than most soils can absorb. If water exceeds the soil’s percolation rate, it can only run off the surface, taking valuable topsoil and nutrients with it. On a slope, drip can be designed for minimum run-off and, is often one way of bringing a hillside into cultivation.
Another advantage of drip is that it can deliver equal amounts of water to plants over a wide area. This is very hard to accomplish with other methods of irrigation.
A drip irrigation system is easy to install. Since no trenching is needed, it can be installed in an existing landscape with no damage to plants’ root systems.
Drip irrigation also allows for watering of a large area from a small water source, since it uses water more slowly than other methods.
Installing drip to new plants will help them develop deep roots which are more resistant to dry spells.
Another great advantage for a farmer is time saving. The simple action of opening a valve replaces all the time spent watering by hand. With the addition of an automatic timer (in advanced settings for commercial farmers), allows attendant to go on vacation or cope with a busy schedule while the garden flourishes without attendant.
It also allows fertilisation and irrigation to be done at the same time, a process called fertigation. This saves time as time that was supposed to be used for the two different operations separately is reserved for other activities.
Once the irrigation system has been set up, it can go for years and hence become cheaper in the long run.
With the above mentioned advantages of drip irrigation, I don’t see any reason why a farmer would not embrace it. So many companies in Zimbabwe are now selling drip irrigation kits, affordable to smallholder farmers. Farmers are also free to purchase and install drip kits which fit well onto their fields or gardens. This is the way to go and cope up with the challenges of irrigation.
