Onion farming using drip irrigation
Onion farming using drip irrigation is considered as the best method of watering onions. Drip irrigation is slow and ensures an even application of low pressure water to soil and plants using drip tapes tubing and emitters placed directly at the plants root zone. This method of onion irrigation allows very little evaporation or runoff, saves water by directing it more precisely, reduces the transmission of pathogens, and produces fewer weeds. It also reduces the transmission of disease causing microorganisms and minimizes weeds invasion in the onion field.
Why onion farming using drip irrigation is the best.
Onion drip irrigation maintains desired soil moisture content
Maintaining the desired soil moisture content with drip irrigation has got some of the benefits to a farmer since it minimizes excessive root growth and it also reduces the risk of bulbs rot disease and bulb splitting.
Onion drip irrigation reduces fertilizer and nutrients wastage
The onion plants have a shallow, fibrous roots system, therefore fertilizers applied at the start of the season end up getting scattered below the root zone by the rain drops, thus making the nutrients unavailable to the crop. The drip irrigation offers consistent nutrition that always reaches the roots and gets retained thus helps to eliminates and minimizes waste.
Drip irrigation reduces the chances diseases invasion in onions
With drip irrigating, water is directed directly to the onion roots, thus leaving the leaves dry. Less moisture content on the leaf significantly reduces onion diseases such as Downey Mildew or bulb rot, thus minimizing crop loss and scaling up production up to 40 percent higher yields.
Drip irrigation in onions ensures efficient fertigation:
Onions need soluble minerals to grow especially phosphorus, which has low mobility within the soil. Which means that drip irrigation is the only option that can be used to apply consistent small doses of mineral nutrients and fertilizers as close to the active root hairs as possible to support boosting of mineral uptake by the onion plants.
What to consider when designing the onion farming using drip irrigation system.
Nature of the field or site
When designing onion drip irrigation system, it is better to identify the onion roots irrigation zones. This can be done based on various factors factors such as land topography, length of the field, soil condition, optimal drip tape run length, and filter sizes. Once the zones are assigned and the drip irrigation system designed, it is possible to schedule irrigations to meet the unique needs of each zone.
Drip system uniformity
Onions plants have got a very strong positive yield and very sensitive to wet soil, yet exhibit increased risk of decomposition in over wet soil. This therefore means that the drip system should be carefully designed to apply water uniformly. In excessively dry areas production curve reduces, and the disease and nutrients loss are promoted in excessively wet areas. By applying drip irrigations, the minimum water application uniformity for onion rangers between 80 – 90 percent.
The onions bed design specifications
When designing bed rows and furrows for onions, special configurations should be taken care of in terms of spacing and bed height. Spacing between the rows should be between 33 inches to around 50 inches. The 50 inches is the distance between the furrows. The double rows are spaced 20 inches apart and consist of two onion rows spaced at a distance of 4 inches apart. Drip tapes are installed 5 to 8 inches deep in the bed center, between the two double rows, at the time of planting. The tape emitters should be spaced 8 to 12 inches apart. This bed configuration minimizes the use and cost of drip tape per acre. On the other hands bed configurations have been used successfully, especially in soils where the water will not wick to the side more so for one tape to serve a conventional bed.
How do you install drip irrigation system for onions farming?
Onions drip irrigations is a very important practice that can be used to mitigate the impacts of drought and waterlogging in an onions field. It makes use of a system of tubing or tape that allows water to seep into the soil without wetting the field surface that may cause nutrients loss and disease invasion in onions. Drip irrigation in onions reduces the rate of water consumption as it provides a more accurate way to irrigate your onion crop for a large yield.
- For you to come up with a simple design drip irrigation system for your onion field, the following installation guide may direct you to come up with a simple design layout.
- The proper choice should be made whether to come up with raised beds or just to a plain field to install the proper drip irrigation system.
- You need to create a 4-inch-deep furrow between your onion rows using a jembe, hand trowel or furrow excavating machine. You have to make sure that the furrow is at least 10 inches away from your onion roots sprouts more so if you do not grow them in rows. This is because placing the drip irrigation furrow lines too close may cause waterlogged soil conditions.
Drip system lateral installation
- Place the laterals or a drip tape into the furrow. Measure the desired length of the furrow then cut it using gardening shears, if necessary. The tape should be extended far enough to reach the mainline of water supply, main pumping unit or a nearby water source.
- Install the drip irrigation connector and merge it to the mainline of water or pumping station. Connect the system with backflow preventer, pressure regulator, filter and tubing adapter. Then now attach the tape to the drip irrigation’s tubing adapter. Turn on the water at the main pumping unit.
- Confirm the drip tape within the furrow and make sure that it fills and seep water continuously into the soil, then turn off the water in order to finish up with the installation.
- Fill up the furrows with the topsoil removed at the project’s inception using the hand trowel. Do not compact the soil down as this may cause breakages of the underlying pipes. Finally allow it to remain loose and well drained.
- Turn on the water at main control unit, and then Press a moisture meter into the soil near the farthest onion plant. Check if the flow is smooth then Turn off the water when your meter indicates that the top soil cover is damp or approximately the depth of the onion bulbs.
- You may spread a layer of mulch across the soil to retain moisture between irrigation periods though this is not compulsory unless there is possibility of doing it.
Specifications and design of onion farming using drip irrigation.
When designing the field for onions drip irrigation, consider the right measurements of the field, spacing, emitter’s size and the water pressure.
- The onion beds should be 1.5 meters wide, having 3 rows of drip lines and about 30 centimeters drainage height.
- The drip irrigation tapes should be of three rows of drip lines, which should be 30 centimeters apart.
- The drip lines should be laid 20 centimeters from the edge of the bed.
- When irrigating, use closely spaced emitters with spacing of 15 – 20 centimeters apart and below.
- When approaching harvesting season, probably two to three weeks, and the rate of watering should be minimized since at this time of growth the mature leaves of the onions begins to drop.
- The maximum pressure exerted by the drippers or emitters should range between 10 – 35 psi.
- When designing of drip irrigation system for onions, the rate of solar intensity or solar exposure should be maintained at an average range of 10 to 12 hours for bulb formation especially in areas experiencing warm climatic conditions.
Maintenance of Onion farming using drip irrigation system.
Check for any for any leakages or breakages
Breakages and leakages may occur at different sections of the system unexpectedly as a result of damage by animals, or farming tools. The system should be monitored to inspect the lines for physical damage
Regular chemical applications
In the drip system for onions, the rate of water flow progressively declines during the season, and the tape may be slowly plugging thus resulting in severe damage to the crop. Applications of chemicals especially chlorine through the drip tape will help minimize clogging of emitters and drippers. This is because the algae growth and biological activity in the drip tape are usually high.
Regular check of the flow meter
The water flow meter in an integral part of the onion drip irrigation system and the gauge readings should be recorded regularly. This may be helpful to a farmer as it provides a clear indication of how much water should be applied to each root zone. The water flow records can be used to detect deviations from the standard flow, which may be caused by leaks in the system or by clogged lines.
Drip tape emitters
These are emitters determine the flow rate of water into the onion field. The drip tapes with lower water application rates make low-intensity and high-frequency irrigations more feasible by improving wetting pattern and uniformity. Low flow emitters with 0.15 gal per hour and ultra-low flow emitters with 0.07 gal per hour are two of the emitter’s options that is commercially available for silt loamy soils. The limitation of ultra-low flow emitters became visible when these two types of emitters were compared against each other. Ultra-low-flow emitters reduces the yield of the largest bulb size class of onions compared to low-flow emitters. The ideal emitter flow rates usually depend on the soil type.
Advantages of drip irrigation in onions farming.
- Extensive land leveling is not required, drip irrigation can be employed in all landscapes;
- Irrigation water can be used at a maximum efficiency level and water losses can be reduced to a minimum;
- Soil conditions can be taken into account to a maximum extent and soil erosion risk due to irrigation water impact can be reduced to a minimum;
- Fertilizer and nutrients can be used with high efficiency; as water is applied locally and leaching is reduced, fertilizer and nutrient loss is minimized
- Reduced risk of groundwater contamination).
- Weed growth is reduced as water and nutrients are supplied only to the cultivated plant;
- Positive impact on seed germination and yield development;
advantages of drip irrigation in onions farming continuation
- Low operational costs due to reduced labor requirement, in particular energy cost can be reduced as drip irrigation is operated with lower pressure than other irrigation methods
- Turbulent flow through the dripper reduces likelihood of clogging
- Uniform flow rate
- Raised barbed outlet prevents water runoff along the drip lateral
- Resistant to chemicals and fertilizers used in landscape applications
- Constructed of UV-resistant, durable plastic material to withstand the most adverse conditions
- We can use recycled water safely.
- We can irrigate water in irregular shaped lands.
Disadvantages of onions drip irrigation system.
Being that drip irrigation system is a very important tool to a farmer, it also has some few disadvantages.
- Onions drip irrigation is very expensive due to high initial cost to poor farmers.
- This make it difficult for most farmers to consider other methods of irrigations that are cheap, flexible durable and the one they can afford.
- Clogging of drippers and emitter is a common agenda in all drip irrigation systems. It may thus discourage most farmers to invest on this drip system of irrigation
Onion plants population
Drip irrigation ensures that the entire top of the onion bed is wetted. This makes farmers to assume that more onions could be planted per acre by spacing them closer together.
This technique results in increase in the total number of onions. Narrow spacing may result in lower value onions. In order to optimize financial returns, an onion farmer must consider the influence of plant population on bulb size.