Subsurface Drip irrigation is a game-changer for agriculture producers, providing precise water delivery right where it’s needed most. At NutraDrip Irrigation Systems, we’re dedicated to helping Midwest growers optimize their sub surface drip irrigation systems for maximum efficiency and crop yield. In this blog, we’ll cover the essentials of buried drip lines: what they are, how they work, and how to maintain them to ensure long-lasting performance.
What is Drip Line irrigation?
A drip line irrigation system consists of many polyethylene tubing installed in the ground that delivers water directly to your crops’ roots. The key component of a subsurface drip irrigation (SDI) system lies in the emitter that is extruded into the tubing, which controls the flow of water. There are emitters welded in the drip line and are typically every 27 inches in the tubing, depending on the type of drip line NutraDrip specified for your field.
Emitters should always be installed facing up to prevent clogging and ensure consistent water delivery. The cleanest water is on the top of the dripline, small particles will settle in the dripline and will be removed through a water and/or air flushing process.
Types of Emitters in an SDI system
There are two main types of emitters used in drip irrigation systems designed by NutraDrip with @netafim tape/tubing:
Pressure Compensating Emitters: These emitters feature a silicone diaphragm built into the emitter, which is composed of three parts: a cap, a top, and the diaphragm itself. If you were to cut one open, you would see this small silicone diaphragm inside. As the system’s pressure increases, the diaphragm adjusts by closing the orifice, making the opening smaller. This ensures that the emitter releases a consistent amount of water regardless of the system’s pressure.
Blown up model of pressure compensating emitter.
Non-Pressure Compensating Emitters: The non-pressure compensated emitter has a simpler design. These emitters do not adjust for pressure variations, making them suitable for flat fields or those with uniform slopes. Water flows into the emitter, travels through it, and then drips out at the end.
Blow up model of non-pc emitter.
Graph:
This chart shows us how these irrigation emitters work. The horizontal axis is pressure, the vertical axis is flow. Green line is the pressure compensated or DNPC 0.16. This model is what we use most on pressure compensated fields. As you follow the green line, you will see once the pressure hits 6 PSI of pressure, the flow stays the same.
The two Aries Flow models (.11 and .18) or orange and yellow lines, you can see the flow increases as the pressure increases. We’ll use these in areas where there is flat fields or where there is uniform slope. These are non-pressure compensated lines.
As part of the engineering process, we assess factors such as friction losses, elevation changes, hydraulic parameters, and overall uniformity to determine the most suitable drip line or emitter for your field.
Drip Line Diameters
Drip lines come in various diameters, with the most common being 5/8 inch and 7/8 inch. At NutraDrip, we primarily use these two sizes for our installations. Other sizes include 1 1/8 inch and 1 3/8 inch.
What is a drip irrigation Coupler?
These are repair couplers used for splicing or making additions and repairs. The irrigation coupler consists of a simple nut, on each end of the coupler, that you twist into place., Pinch the drip line at the end with your finger, twist onto coupler to secure, and then tighten with green nut. When properly installed, these couplers ensure a secure connection that won’t come apart. We offer these repair couplers for all sizes of drip line.
What is the Maintenance and Longevity for an SDI system?
To ensure your drip line system lasts after installation (link to YT (275) Installing Subsurface Drip Irrigation – YouTube), regular maintenance is crucial. One of the most important aspects is flushing the system to remove fine solids that can accumulate over time especially if we are working with manure water, surface water, silt, or fine sand. This will accumulate at the bottom of the drip line. To get that debris flushed out, we must increase the velocity in the drip line to 1 foot per second. Here’s a quick guide on how to flush your system:
Flush Velocity: The velocity inside the drip line should reach one foot per second to effectively clean out debris.
Flushing Time: Calculate the time needed to flush based on the length of your field. For example, a 1200-foot field requires 20 minutes or 1200 seconds of flushing.
Frequency: Flushing is crucial, especially with dirty water. If you have clean well water and irrigate less than 12 inches a year, flush once a year. For surface water irrigation between 6 and 12 inches a year, flush twice a year. If using manure water or dealing with fine solids, you might need to flush monthly. Proper and regular flushing is essential for system maintenance.
Making Sure It’s Clean: When you start to flush, you’ll get some nasty looking water coming out. Usually, you want to flush until the water is clean and it looks like you’ve carried all the sediment out.
Zones: Each zone typically has two flush valves and those need to be opened individually of each other. In other words, you need to open one flush valve, flush it for maybe 30 minutes, then close it. Open the other flush valve up and flush that half of the zone for 30 minutes. You can flush multiple zones at a time, but only one half of each zone at a time. Depending on your pump capacity, it will tell you how many of those you can flush at one time.
Monitoring and Preventive Measures
Ensuring the longevity of your drip irrigation system involves regular maintenance, especially when it comes to cleaning the emitters. Depending on water quality, these small components can require preventive cleaning to maintain optimal performance. We recommend running a cleaning solution through the lines after every 24 inches of water application, although the frequency may vary based on specific conditions.
For detailed guidance, you can refer to the comprehensive drip irrigation maintenance document provided by Netafim, which offers valuable insights into managing water quality.
The primary concern here is the buildup of minerals such as iron and manganese, which can gradually restrict the flow through the emitters. Monitoring these conditions over time is crucial. A noticeable drop in flow rates can serve as an early warning sign of potential clogging.
To effectively manage these issues, consider setting up alarms on your system controller to track flow variations. If there’s a significant reduction—for instance, from 500 gallons per minute at the start of the season to 400 gallons per minute later on—it indicates a 20% decrease in flow due to emitter blockage. In such cases, it’s important to take water samples and evaluate the situation.
Utilizing cleaning agents like acid, chlorine, hydrogen peroxide, or a combination thereof can effectively remove mineral deposits and restore optimal flow rates. It’s worth noting that certain fertilizers, such as 10-34-0, can contribute to emitter clogging, whereas acid-based fertilizers can help keep them clean.
At NutraDrip, we offer specialized services including acid flushing and the injection of chlorine or hydrogen peroxide to ensure the long-term performance of your system. With regular irrigation monitoring and preventive maintenance, you can significantly extend the lifespan of your drip irrigation system, maintaining efficient water delivery for your crops year after year.
Iron build up in an emitter.
Root Intrusion
Watch out for root intrusion in perennial crops such as alfalfa, where roots are active year-round, constantly seeking water. Insufficient water supply can prompt roots to invade emitters, causing blockages. Applying chemicals to prevent root intrusion or dissolve roots inside emitters can be effective preventive measures. Taking these precautions can help prevent costly maintenance problems in the future.
Conclusion
Understanding the basics of drip lines, from installation to maintenance, is essential for maximizing the efficiency and lifespan of your irrigation system. By choosing the right emitters, regularly flushing your system, and staying proactive with maintenance, you can ensure that your crops receive the water they need without waste. At NutraDrip, we’re here to support Midwest growers with top-quality drip irrigation solutions tailored to your specific needs. Keep your drip lines clean and efficient and watch your agricultural irrigation fields thrive.
