By fred kipng’etich
As climate change effects make rain seasons unpredictable, farmers need to plan on how to conserve and use water wisely, to enable sustainability in food production. There are various irrigation systems available to farmers today.
Deciding on the best irrigation system for your farm will depend on factors such as type of crop, typography, soil type and availability of water and power to drive the system. Though there are many different irrigation solutions in the market today, drip-irrigation remains the most effective system to deliver water and nutrients to crops.
Benefits of drip irrigation
Drip-irrigation consists of dripper lines that deliver precise amounts of water and soil nutrients directly to each plant’s root-zone. The result is each plant gets exactly what it needs, when it needs it, to grow optimally.
Farmers can produce higher yields while saving on water, energy and even crop protection products. That means lower input costs and higher returns.
Farmers using drip irrigation method to irrigate their crops can save more than 50 per cent of water and manure compared to other methods such as overhead irrigation. This is because, in drip irrigation, water sips slowly to the root zone of the plants either onto the soil surface or directly into the root zone through a network of valves, pipes and emitting tubing (drip tape). On the other hand, overhead irrigation methods encourage accumulation of moisture in the environment. Moisture creates good microclimate for disease causing germs like fungi to thrive. But drip irrigation limits water supply to the stem base and is absorbed directly to the soil, without resulting to soil erosion or run off.
At the same time, drip irrigation gives farmers more latitude to control water supply. If there are no plants at given outlets, the farmer can temporarily close those holes with a cello tape, allowing for the water to flow to other areas instead of letting it go to waste.
Consistent amount and rate of flow of water and any other resources included leads to equal supply of nutrients. For this reason, the crop growth rate and final yield is uniform.
Initial setting up of the pipes requires manual input but later application will be easy because a farmer will only require to turn on the water tank tap on. The water trickles onto the root zone as the holes are already fixed, and the farmer does not need to keep moving the sprinklers or use water cans across the plant rows.
Localized release of water also reduces growth of weeds. Drip irrigated crops grow faster than weeds because they have sufficient water and nutrients for growth compared to weeds.
Maintaining the system
To maintain the drip irrigation system, clean the screen filters every day before using the drip system. The flush valve is assembled at the end of sub main pipe and is opened weekly to let the water flow till clear water comes out. Each month, the end caps of every drip tape line should be opened to remove accumulated dirt and particles inside the drip tape.
Drip-irrigation requires low energy input as gravity plays a big role in the system. This means lower electricity bills, or no bills at all if you install solar power, which is ideally suited to drip-irrigation.
Frequently asked questions by farmers.
When is the best time to do drip irrigation?
Early morning watering is the best so that the soil warms up during the day.
Which drip tape thickness should I use?
0.4mm thickness and above are well suited for tropical open field crops.
What is the right pressure for drip irrigation?
The pressure of water depends on the topography of the land. The more gravity the greater the pressure. To increase the amount of pressure, use a pipe with less width.
How do I select my emitter spacing?
Emitter spacing is determined by crop spacing. Closer crops have closer emitters.
How long should I drip irrigate?
You should drip irrigate until the soil holds enough water without runoff.
How exactly does drip irrigation work?
By allowing the drip emitters to irrigate until the soil around the root zone has enough moisture. Drip irrigation is done by opening the main water valve from the main tank/ source. Once the water gets to the farm, the farmer will open the respective valves to each block to irrigate block by block. The time of irrigation will depend on the flow rate and the water needed.
How many emitters can I put on a drip line?
There is no limit to the number of emitters, put them according to the number of trees. Vegetable drip lines are pre-perforated and so one does not add emitters. The number of emitters depends on the emitter spacing on the drip line.
What are the two main types of drip irrigation?
Pre-perforated drip pipes and button drippers.
Irrigation kits design depend on the size, shape and topography of the land. The sizes vary from one care kit, a half an acre kit, a quarter an acre kit and a sixteenth of an acre kit. If the land is larger than one acre, the farmer can buy one-acre kits that can serve the size of the farm. To install, a technician first surveys the land to determine the design of the system.
What is the estimation of the yields I would make using drip irrigation on an acre piece of land?
From an acre of onions for example, a farmer can harvest about 16 – 20 tonnes of onions when using 3 driplines bed under good agronomical practices.
From one care farm of watermelons, a farmer can harvest about 40 tonnes when using one drip line bed, under good agronomical practice.
What are the downsides of using drip irrigation?
It is important to note that the installation process takes time. Also, under extreme weather when the heat is high, tubes can get broken. Thirdly, the tubes can be clogged, by residues, but this can be remedied by using an organic chemical known as super link, to unblock the drip lines.