Irrigation timers in Kenya are the brain of automatic irrigation systems. These systems enable the farmer to irrigate the plants at the right time and use the right quantities of water. Drip, sprinkler, or center pivot irrigation systems can use these controllers.
Features of irrigation timers in Kenya
The vital features of all irrigation timers are;
- Calendar and clock settings – these settings enable the farmer to set watering times and cycles.
- Manual start and operation station – the manual start enables the irrigation to be started without affecting the irrigation timer settings. The manual settings prove very useful, especially during maintenance practices.
- Master switch – the master switch can overturn the automatic functions.
- Master valve – opens and closes, allowing or preventing water flow to the irrigation system.
- Rain sensor – This sensor’s function is to detect rainfall and stop irrigation. It helps conserve water since no irrigation is needed when it is raining.
- Pump start lead – it activates the pump start relay, which turns on the pump. The pump start relay’s function is to detect signals from the controller. A controller should not be connected to the pump directly since it will be damaged.
- Battery backup – irrigation timers in Kenya use electricity to operate. To cater to power blackouts, a battery backup is needed. The battery will allow the controller to keep the date and times set even though no irrigation will occur until power restoration.
- Non-volatile memory enables the timer to keep the time and date settings even without the battery in case of power outages.
- Delay – this allows to fully close off valves in one zone before opening in another location.
Types of irrigation timers in Kenya
There are three main groups of Irrigation timers in Kenya. These three groups are mechanical, electronic, and hybrid timers.
Mechanical timers
Mechanical timers use gears, springs, dials, and motors to operate. furthermore, they depend on power input by humans to turn the spring. The timers are not prone to power shortage issues making them more suitable for remote areas. They lack many features and are cheaper than other types of irrigation timers. Also, when turning the timer, we compress a spring inside. As the spring unwinds, it turns the gears that move the dial. The timer finishes one cycle after the spring has completely unwound.
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Electronic timers
Electronic timers make use of a digital screen. Unlike mechanical timers, these lack moving parts. They use integrated circuits for the clock, programming features, and memory. Since they use integrated circuits, they have a lot of features. The downside to these irrigation timers in Kenya is that they are dependent on electricity and are costly. Likewise, Smart electronic timers can adjust the water scheduling automatically.
Hybrid timers
These timers use the best qualities of both mechanical and electronic timers. They have an electric clock and mechanical switching. Furthermore, hybrid timers have more features than mechanical timers and are not prone to power shortage issues since they use motors, springs, and gears.
How to choose an irrigation timer in Kenya
The key questions to be asking when choosing irrigation timers in Kenya are:
- Is it going to be mounted outside or inside?
- What number of zones are there?
- How many programs are needed?
Outdoors or indoor mounting
Indoor irrigation controllers are kept inside the house or in covered rooms to prevent damage from weather. These controllers can be plugged into the house sockets since they come equipped with an external transformer. The transformer steps down the voltage from the sockets enabling efficient working operations of the controller. Outdoor controllers are weather resistant and durable. They have an internal transformer making them usable as indoor controllers by adding a three-prong plug and a power cord.
The number of zones in the irrigation farm
Irrigation zones refer to areas controlled by irrigation controllers. Most small-scale farms require about two to nine stations, while commercial farms need 32 to 48 zones. When deciding on irrigation timers in Kenya, it is best to choose one with extra stations to cater for future expansion.
Number of programs
A program in irrigation controllers refers to a set of instructions on the watering of crops on that day. Timers can have 1 – 4 programs installed, with most of them having two or more programs. The number of programs available in the controller determines the number of instructions given.
Water timer power sources
The common types of water power sources available for irrigation timers in Kenya are;
- Electric powered water timers – these controllers do not need batteries. They are susceptible to power surges, and their placement is limited to areas near power outlets.
- Battery-powered controllers – they can be placed anywhere on the farm, and the rate of battery replacement depends on the usage.
- Solar power – solar-powered timers do not make use of batteries. The performance is affected by the weather.
Types of irrigation systems in Kenya
There are four major types of irrigation systems in Kenya. These are sprinkler, drip, surface, and subsurface irrigation. We can use irrigation timers in Kenya to automate these irrigation systems.
Sprinkler irrigation
Sprinkler irrigation systems distribute water to the plants in the form of artificial rainfall. It is an effective water distribution method, especially in large areas with fewer winds. Sprinklers are high-pressure equipment that needs the support of a pump to distribute the water. A farmer should not water plants with weak stems using this method because of the high water pressure. The water pressure will break the plants reducing their quality. Farmers should not irrigate plants that have leaves sensitive to water using sprinklers, e.g., tomatoes and lettuce. We should do sprinkler maintenance consistently to avoid blockage of the sprinkler nozzles.
Farmers can use irrigation timers in Kenya in sprinkler systems to automate the watering process. The timer can control the system by controlling the main valve. When it is time to irrigate, a signal is sent to the main valve, allowing water to flow into the system. After a set irrigation time, another signal is sent to the main valve to stop the water flow.
Drip irrigation
Drip irrigation systems are precision irrigation methods that deliver water to the crop root zone. We reduce the water loss by other means by using this system. Water distributed using this system is under low pressure; hence, you don’t need pumps to deliver water to the crops. Farmers should filter out the water to avoid emitter blockage. The advantages of using drip irrigation systems are weed control, soil erosion control, reduced risk of pests and diseases, water-saving, and energy saving. The use of irrigation timers increases water application efficiency on the farm. Drip irrigation already has a water efficiency of 95%. With the addition of irrigation controllers, we can increase efficiency.
Surface irrigation
Surface irrigation involves methods that allow water to flow over the farm by gravity. These methods utilize a lot of water, and evaporation and runoff account for most of the water lost. This method works best in soils with poor infiltration rates, i.e., clay soils. Surface irrigation methods include;
- Basin irrigation – this method involves building bunds on the farm, allowing water to flow between the bunds.
- Furrow irrigation – in furrow irrigation, long trenches are dug and filled with water from rivers or canals
- Border irrigation – this method of irrigation involves the supply of water between strips of land using gates or siphoning using pipes from rivers or streams. Surface irrigation methods are hard to use with irrigation timers.
Sub-surface irrigation
Sub-surface irrigation involves water supply to the crops directly to the soil layers. Also, we can categorize this method into two, i.e., artificial or natural sub-surface irrigation. Natural sub-surface irrigation involves water leaks from sources of water like underground streams. Artificial sub-surface irrigation involves the application of water beneath the soil using pipes. The depth of the pipes should be more than 40 cm to avoid damage by machinery. This method helps in water-saving by avoiding water losses through evaporation. Also, Irrigation timers in Kenya serves as automation subsurface irrigation.
Smart irrigation timers in Kenya.
Smart irrigation controllers can monitor and control water and nutrient supply to the plants. They can be categorized into two major groups, i.e., Climate-based controllers and Soil moisture sensors controllers.
Climate-based controllers
These irrigation timers in Kenya are also known as evapotranspiration controllers. They depend on evapotranspiration data to decide when to irrigate. Climate-based controllers make use of local weather reports to adjust the irrigation schedules. We can group them into three types.
- Historic evapotranspiration controllers – these controllers use pre-programmed water use curves of different regions from historical data.
- Signal based controllers – the timers make use of meteorological data from available public sources, and then the evapotranspiration data is computed.
- On-site weather measurement controllers – On-site weather measurement controllers take real-time measurements and compute the evapotranspiration data continuously. The data computed is used to adjust the water supply to the farm.
Soil moisture sensors
Soil moisture sensors use sensors in the ground to decide when to irrigate. Unlike the climate-based irrigation controllers that use evapotranspiration data, soil moisture sensors use volumetric soil water content. The volumetric water content refers to the portion of the whole soil volume occupied by water. We set the controller to start irrigating when the volumetric water content reaches a certain threshold (usually 10% -40% ). The threshold chosen is dependent on the soil type and vegetation that has grown in the area.
Smart irrigation add-on sensors
We add add-on sensors to smart irrigation timers to improve the system’s efficiency. Examples of add-on sensors we use are rain, freeze, wind, soil moisture, and irrigation flow.
Rain sensors
Rain sensors interrupt the irrigation cycle when it starts to rain. This helps in saving costs and water due to unnecessary runoff. Place Rainfall sensors in open fields to avoid interruption. There are three types of rain sensors available, i.e.,
- Cup/ basin rain sensors. As it rains, water accumulates in the cup/ basin, and the basin’s weight interrupts the irrigation cycle. These rain sensors are prone to debris, and you should clean them regularly to avoid errors.
- The second type of rain sensor uses two electrodes and a cup. As it rains, water accumulates in the cup.
- Expanding discs rain sensors – these rain sensors make use of discs that expand as they absorb water. When the discs expand to a certain point, they activate a switch that interrupts the irrigation cycle. The wet discs stop the irrigation cycle until they dry up. Unlike the first two types, disc rain sensors have low maintenance and high reliability. It would help if you replaced the discs at least once per year.
Wind sensors
The wind is a significant hindrance to irrigation, especially sprinkler irrigation. It reduces the amount of water infiltrating the soil and disturbs the water application uniformity. Wind sensors help detect wind speeds and stop the irrigation cycle once the wind speed exceeds the set threshold. These sensors help improve on the efficiency of water distribution.
Soil moisture sensors
Farmers use these sensors to measure the amount of water in the soil before an irrigation cycle. The cycle, interruption occurs when there is excess water, preventing water wastage. Some of the soil moisture sensors also have soil freezing sensors. These sensors interrupt the irrigation cycle once the soil temperature falls below 00C
Freeze sensors
Freeze sensors interrupt the irrigation when the temperatures go below 00 C. In addition, Shutting down irrigation water at these temperatures assists in lengthening the life of the irrigation system and avoiding the icing of paths.
Irrigation flow sensors
We use water flow sensors to detect the water conditions as it moves in the system. These devices can measure the flow rates and amount of water delivered. more ever, the irrigation flow sensors detect how fast or slow water is moving and send the data to the controller. A farmer can use this information to detect problems in the system and conserve water. If there is a leakage in the systems, the sensors will detect low water pressure and take the appropriate measures. When the water flow is high, the sensor detects it and sends the information to the controller, reducing the amount of water flowing.
Recommendations for irrigation timers in Kenya.
Irrigation controllers utilize power to operate, and the usage has cost implications. A farmer can follow these recommendations to reduce the cost of using irrigation timers in Kenya.
- You should schedule irrigation to happen very early in the morning. It is best to irrigate between four and nine in the morning when the winds are not strong, and the temperatures are cool. This will help reduce water loss.
- Adjusted Irrigation timers to give out the right amounts of water to avoid water runoff.
- Rain sensors are beneficial because they help avoid irrigation when it is raining, saving on costs.
- Wind sensors reduce water loss by the wind in sprinkler irrigation systems .
- Finding out your irrigation water output will help in better scheduling using the timers.
Advantages of using irrigation timers in Kenya
- Convenience – Irrigation timers in Kenya turn on automatically without human aid. This removes the human error of forgetfulness.
- The owner must not be present to turn on the system.
- Irrigation timers can supply the right quantities of water needed at the right time. Some smart controllers are even able to adjust the water output throughout the season.
- Low production costs. The efficient water application saves on energy and water costs.
- Fertilizers application- When the substrate quantities are low, the sensors can detect the change and fertilizer supplied through fertigation.
- Reduced nutrient leaching – the use of sensors in the soil and irrigation timers assists in ensuring an optimum supply of fertilizer to the soils. By doing so, we avoid nutrient leaching.
- Smart irrigation timers can collect data on the soil and plant conditions enabling the farmer to make informed decisions.
- Increases yields – using intelligent irrigation timers, ensures water supply and nutrient supply at the rig