Subsurface Drip Irrigation FAQs: Answers from Local Experts

Subsurface drip irrigation (SDI) waters your crops or turf using underground drip lines. It’s important to understand the yield and quality advantages, as well as the cost savings and flexibility these systems bring to your irrigation management strategy. Do you run a commercial, agricultural, golf, or large residential irrigation system? These FAQs provide everything you need to get started with your upgrade or installation project.
 

What Is Subsurface Drip Irrigation?

Subsurface drip irrigation systems include drip lines placed underground, not on the soil surface. They distribute moisture directly to the root system via small emitters. Some of the advantages include less water loss due to evaporation and leakage and low maintenance requirements. Essentially, SDIs give farmers, ranchers, golf course managers, and other stakeholders an effective way to hydrate plants and turf while conserving water.


How Are SDIs Installed?

Burial depths for driplines can vary, but we recommend lines buried roughly 14 inches below ground. They distribute water slowly to prevent evaporation and runoff. In this way, subsurface drip irrigation delivers moisture and nutrients steadily to the root zone. With regular use, SDIs can help to promote healthy plant growth by deterring diseases. 

Here’s an overview of the installation process:

  • Plan and design the system: This includes the following components:
  1. Water source 
  2. Filtration system 
  3. Mainline and sub-main
  4. Controllers
  5. Fittings
  6. Valves
  7. Driplines
  • Install the mainline, sub-main, filtration system, and valves, keeping local codes top of mind.
  • Install the driplines with an irrigation trencher, maintaining a uniform depth. You’ll need to consider the soil type, topography, and other factors, such as the root structure. 
  • Set up automated controllers and sensors for remote monitoring of soil moisture sensors, pressure gauges, flow meters, and other components.
  • Flush the system to remove air pockets and clogs.
  • Measure flow rate and pressure at various points to test for performance gaps and leaks.
  • Make any necessary changes to the configuration. 

Be sure to check out our Expert Guide to Irrigation Design for assistance and ideas.


Where Are Subsurface Drip Systems Installed?

SDI systems are perfect in areas with limited rain and water resources. They can efficiently water crops on any type of terrain, including:

Keep in mind that subsurface drip irrigation systems require careful planning. Be sure to reach out to our team if you need assistance with SDI design, installation, and management.

 

What Are the Advantages of Subsurface Drip Systems?

Some benefits of upgrading to an SDI system include:

  • Greater yield and quality
  • Cost savings 
  • Effective water usage
  • Improved soil development 
  • Effective fertilization (less runoff)
  • Better irrigation infrastructure
  • Increased flexibility


How Does SDI Improve Yield and Quality?

Subsurface drip irrigation has had positive results of higher yields and crop quality with various crop types. The slow, steady hydration promotes hardy plant growth. You can precisely customize water delivery rates for landscaping, golf, or agricultural purposes. Thus, each plant receives the exact amount of water required, with minimal waste.

Whereas overhead sprinklers leave behind wet foliage susceptible to disease, subsurface drip irrigation delivers moisture to the roots far below the surface. In drier areas, SDI helps prevent weed germination, leading to a smaller environmental impact and higher crop yields. 


What Are the Major Cost Savings Associated with SDIs?

The initial investment for subsurface drip irrigation is typically higher than for surface or overhead irrigation systems. However, increased yield and lower expenses make it a worthwhile investment for your large residential or commercial property.

Costs savings come in three categories:

  • Lower water usage
  • Reduced labor expenses
  • Lower cost of fertilization

Subsurface drip irrigation uses lower pressure than above-ground irrigation methods, potentially reducing maintenance and pumping costs. The durable polyethylene driplines are buried, limiting damage from any potential surface hazards or troublesome weather. Due to efficient hydration to the root system, SDIs require less water, resulting in a reduction in utility costs. Plus, the slow delivery helps prevent salt buildup that tends to hinder water absorption. 

These automated systems reduce labour requirements and save time for agribusinesses, golf course managers, and property managers.

The precise dosage and timely application can reduce fertilizer costs and nitrate losses. Fertilizers and nutrients fed through the driplines save you money on separate equipment required by overhead and surface irrigation systems. Direct application can also improve fertilizer efficacy.


How Can Subsurface Drip Irrigation Lead to More Efficient Water Usage?

The slow application rate limits surface water buildup. That can result in less erosion and deep penetration into the soil, so you don’t have to irrigate as frequently as with traditional watering methods. 

Since the water delivery with an SDI system is underground, you don’t have to worry about water loss due to runoff and evaporation. Irrigate without wasting a precious drop of water with an earth-friendly irrigation solution.

SDIs also conserve water below ground, reducing soil evaporation and deep percolation significantly. As a result of slow water delivery, there is less chance that the soil will become oversaturated.

You can also choose the best time to schedule daily watering. By turning the system on in the early morning or late afternoon, you’ll reduce evaporation and increase the efficiency of your irrigation management. 

Point-source drip irrigation devices deliver water directly into the root zone of the crops. These devices are available from trusted suppliers such as Hunter and come with an optional diffuser to further control water flow. They put every waterdrop to good use.


What’s the Impact of Subsurface Irrigation on the Soil?

Subsurface drip watering reduces soil compaction in the bed. Soil compaction often results when heavy irrigation equipment tamps down the soil. This can limit root development and lead to increased erosion if left unaddressed. For example, with overhead sprinklers, water droplets strike the surface forcefully, potentially leading to compaction. On the other hand, drip emitters soak the soil below the surface, eliminating any potential compaction to the crop.


SDI safeguards soil health in three ways: 

  • Water slowly permeates the soil, allowing more moisture to reach the root zone. 
  • There’s little to no erosion or runoff. 
  • Underground irrigation reduces soil crusting.  



How Can SDI Help You Use Fertilizer More Efficiently?

By delivering nutrients and water in the same system, subsurface drip irrigation eliminates the need for redundant systems. It also decreases the risk of fertilizer runoff into nearby streams. You can maximize nutrient delivery and reduce chemical leaching by preventing root burn (deep percolation).

SDI puts fertilizer application directly into your capable hands. If you need assistance planning or installing your subsurface system, we can train you and your staff on how to use it effectively to improve plant hydration and nutrition.

Here are some ways SDI improves your fertilization process:

  • Applies nutritious fertilizer right at the root zone.
  • Gives you complete control over dosage and frequency.
  • Allows you to automate the fertilization cycles. 
  • Gives you the ability to adjust water pH for various formulations, so you can increase the root absorption rate.


What Can I Gain from Adopting an SDI Infrastructure?

One of the biggest arguments for installing a subsurface drip irrigation system is the ability to automate it without a power source on the field, lawn, or course. Since it includes fewer moving parts, an SDI system doesn’t require as much maintenance as an above-ground system.

SDI systems include fewer mechanized parts. Plus, the polyethylene or plastic construction eliminates the risk of rusting and corrosion. With the pipes and driplines buried, there’s a lower risk of vandalism or accidental damage. 

If you have a large area to water, the low flow rate of subsurface systems allows you to water more plants simultaneously. Additionally, you won’t have to spend a lot of time and money on drainage solutions since water is applied directly to the roots, eliminating surface pooling and runoff. 


What Makes Subsurface Drip Irrigation Systems So Flexible?

You can use SDI systems in conditions that make overhead or surface irrigation impractical. Consider the following:

Do you have fields with uneven topography? You can use SDI systems on oddly shaped and surfaced terrain and with various soil conditions. 

Do you need full coverage for water-intensive crops? You can configure your subsurface drip system for 100% coverage. 

How can you maintain uniform water pressure? Contact our sales team for suggestions regarding pressure-compensating driplines to avoid a runoff on sloped or uneven fields.

Do you have a limited water supply? Maximize water usage from your pond or well with a flexible SDI system.

What about fields in full sun and windy conditions? SDI systems aren’t impacted by sun and wind so quick evaporation of water should not be a concern. You can avoid leaf burn associated with overhead systems with the right subsurface drip irrigation setup.


What Are the Best Crops for SDI Applications? 

If you grow cash crops, such as corn, soybeans, and wheat, you should seriously consider the advantages of installing a subsurface system. SDIs also work well in orchards, so find out the best way to optimize the watering strategy for your apples, pears, cherry, and other orchard crops. 

If you grow your own hay or sell forage crops for profit, SDIs are likely to dramatically improve your ROI by saving you money on labour, maintenance, and utilities. 

Do you grow crops, such as vegetables, sensitive to water loss? An SDI system may be the perfect solution for reliable hydration that you can control remotely. Additionally, subsurface systems are a natural fit for crops with a longer growing season and deep root systems requiring effective water delivery. 


How Does Soil Type Factor in the Decision?

There is no specific soil type that works better over another when considering an SDI system; this system can accommodate any soil type, field shape, or uneven terrain. When considering the soil type of your property, the only thing that will differentiate will be the model of the dripline suitable for your application and soil type.

 

What Components Are Essential to a Full SDI System?

While every subsurface drip irrigation system is unique, there are common elements you’ll need in order to optimize your irrigation strategy. 

 

Most SDI systems require the following components:

  • Pump Station
  • Main Filter
  • Secondary back-up filter
  • Mainline (and sub-mains, as required)
  • Lateral lines
  • Control valves
  • Dripline risers
  • Driplines
  • Flush manifolds
  • Air vents and vacuum release valves

You’ll also need a Heavy-Duty Subsurface Dripline Injector, which we can sell or rent to you.

 

Other components that allow you to use your SDI for fertilization and automation include a fertilizer injection system and automated controls. You can also install soil sensors for remote monitoring of moisture levels, temperature, and acidity (pH), among other factors.

 

With a weather station, you can remotely monitor wind speed, solar radiation, humidity, and a variety of other conditions. This allows you to adjust your watering schedule accordingly without manually inspecting various fields and crops. 


Are There Any Disadvantages I Need to Consider with an SDI System?

There are disadvantages and limitations to all irrigation systems. Before making a decision, keep in mind these key factors:

  • Although ROI may be higher, the initial setup cost of an SDI system can often be more costly.
  • A higher level of expertise and experience is needed to master SDI installation and maintenance.
  • Proper routine maintenance and attention to the system are needed to avoid things like clogged drip emitters over time. 
  • May not work well with herbicides that require sprinkler irrigation or rainfall to activate. 
  • Flowmeters and pressure gauges are needed to monitor the system (fewer visual cues compared to surface irrigation).
  • Special skill and care to maintain emitters.
  • Improper operation can lead to salt build-up around the roots.
  • Puts restrictions on tillage options (depends on the depth of till compared to the depth of buried irrigation lines).


Limitations of SDIs include:

  • Not suitable for certain crops that grow below the surface, including sugar beets, carrots, and potatoes.
  • Not helpful with the process of seed germination of shallow-seeded crops.
  • No evaporative cooling is available.
  • Not the most reliable irrigation system if depended on for frost protection of your crops.
  • The wetting pattern may not be wide enough for coarse-textured soils (limits root zone).
  • Unsuitable for water with high iron content.

 

What Is the Life Expectancy of an SDI System?

With proper maintenance, the life expectancy of the SDI system is up to 25 years. It’s not unusual for these systems to keep going strong for over 20 years. When you partner with industry experts to select and install the right components, you maximize the longevity of your subsurface watering system.

 

What Advantages Does SDI Have Over Drip System or Overhead Irrigation?

With SDI, you can achieve better uniformity and water usage because there are no evaporation and runoff losses. If you want to apply your fertilizer through your irrigation system (fertigation), subsurface systems allow you to do so efficiently. 

Compared to overhead and surface irrigation, SDI doesn’t require as much energy due to lower pressure requirements. You don’t have to worry about strong winds or excessive sunlight robbing your plants of vital hydration. It’s all delivered directly to the roots.

Other advantages of subsurface systems include a lower risk of disease propagated by wet foliage. For easy automation and remote access, you’ll get more bang for your buck with SDI systems. Contact the team at Vanden Bussche for a free consultation and to learn more about subsurface drip irrigation.