Drip Irrigation is the most efficient water and nutrient delivery system for growing crops. It delivers water and nutrients directly to the plant’s root zone, in the right amounts, at the right time, so each plant gets exactly what it needs, when it needs it, to grow optimally. It enables farmers to produce higher yields while saving on water as well as fertilizers and energy.
Water and nutrients are delivered across the field in pipes called ‘drip lines’ featuring small units known as ‘drippers’. Each dripper emits drops containing water and fertilizer, resulting in the uniform application of water and nutrients direct to each plant’s root zone, across an entire field.
But just like any other irrigation system, drip irrigation has its own share of challenges. Below are some of the setbacks that farmers can experience when using drip irrigation systems and how to solve them.
A major problem associated with drip irrigation systems is the clogging of emitters, unless preventive measures are taken. Emitter outlets are very small and can become clogged easily by suspended materials (sand and silt), precipitated dissolved salts (mainly carbonates), rust and other iron oxides and organic matter (including plant roots, algae and other minute animals). Clogging can reduce emission rates and cause poor uniformity of water application. Prolonged clogging can cause severe damage to the crop. Clogging also increases the maintenance costs, as it becomes necessary to check, repair or replace clogged emitters and other components. Chemical treatment and proper filtration of water can prevent or correct emitter clogging. The first requirement is to select emitter devices which may require less maintenance. Well-designed filtering systems, when properly maintained, can solve the problem caused by suspended material (sand and silt) and in some cases the organic matter.
Restricted root development of crops
Drip irrigation normally wets only a part of the root zone. Hence, the root distribution is almost limited to the moist zone. Many factors, involving soil and plant characteristics, management practices (amount and frequency of water application) and the design of the irrigation system (number of emitters per plant, placement and discharge rate of emitters) influence the root development of crops. The concentrated distribution of roots may reduce the plants ability to withstand strong winds. Further, the ability of the plant to withstand drought, resulting from any breakdown in the irrigation system, is greatly reduced as water of the wetted zone gets depleted soon and the surrounding region is dry. Careful planning and operation of the irrigation system and prevention of breakdowns will reduce the magnitude of the problem.
Damage from rodents and other animals
There are several kinds of burrowing animals which can cause damage to surface or buried polyethylene laterals. They include rats, mice, squirrels, dogs and rabbits. When present in large numbers, these animals can cause heavy damage to drip irrigation systems by chewing holes in the lateral lines. Use of repellents to keep the animals away and baiting or trapping them are possible control measures. Rats and squirrels can be controlled by adopting subsurface drip systems. Rats generally never cross a wet surface. Keeping the system moist is a possible remedy to control it.
Salt accumulation at the root zone periphery
Where high salinity water is used for irrigation in arid regions, salts tend to accumulate towards the periphery of the wetted zone and the interface between the irrigated and non-irrigated zones in the soil. As the root zone is kept constantly at high moisture level, there may not be any major impact on the crop, but in the next growing season these salts, if not leached away, may damage the succeeding crop if planted on the interface having the salt patch. In regions where drip irrigation is practiced in the dry season with rainfall exceeding about 300 mm in the following rainy season, the salts will generally be leached. Like in other methods of irrigation, good natural or artificial drainage is needed in drip irrigated areas as well. Otherwise, artificial leaching is to be provided once every one or two years.
High cost of drip irrigation systems
The cost of drip irrigation systems is high when compared to surface or portable sprinkler irrigation systems. Drip irrigation systems are expensive because of their requirements of large quantities of piping and filtration equipment to clean and water. However, the cost of drip irrigation systems varies considerably depending on the crop and terrain. Steep terrain may require several pressure regulators in the system. In many situations the benefits of the drip system will usually outweigh the cost of the system, when compared to other methods of irrigation. Selecting widely spaced crops of high market value is necessary to increase the benefit cost ratio in drip irrigation.
Arguably the most common problem we encounter in home irrigation systems is inadequate trenching. Trenching is the most labor intensive part of an irrigation installation, and is therefore often neglected. Unfortunately though, poor trenching can result in pipes being frequently punctured (either by yourself or your gardener), and can lead to frequent maintenance of the system. As a general rule and unless there are extenuating circumstances such as rock or house foundations, pipes should be trenched to a minimum of 400mm below the surface.
As is clear, system flushing and chemical treatments are two vital keys to the success of a drip irrigation system. Maintenance must be done preventively to ensure that systems operate efficiently for as long as possible. If the necessary maintenance activities are done sufficiently and successfully, you will be able to grow more with less without a care in the world.
For any inquiries on drip irrigation; materials, installation or maintenance, contact Mazero Agrifood on 0729777711.