1. What is the most important thing that DRI offers that other forms of irrigation do not?

The DRI system offers control; more control over your water and fertilizer delivery; more control over your maintenance costs, and more control over your ability to monitor when your tree or vine needs water. 

2. How does DRI cut irrigation water use?

Controlled testing confirms that direct delivery of water to the root zone is profoundly more efficient than traditional surface watering methods. Surface watering loses a lot of water to evaporation and run off. DRI does not. A six hour saturation test comparing DRI with drip, showed that DRI almost stopped emitting water once the column around the DRI unit was fully saturated. Flow of water is significantly reduced once a full level of saturation has occurred in the column of soil, resulting in about a 60% savings of water when compared to standard drip. 

3. How does DRI dramatically reduce maintenance costs?

Consider how many of your maintenance costs are actually created by surface watering. 

A. Energy - The biggest cost of irrigation is energy. If you cut your water consumption in half, you will effectively reduce the energy required to pump it by half. 

B. Soil amendments - Many orchards are spending on average $135.00 per acre every year for soil amendments intended to enhance the soils ability to absorb water and fertilizer. That cost translates to about $27,000 a year for a 200 acre orchard. This cost could be completely eliminated because the DRI delivers water and fertilizer directly to the root zone. Soil PH can be achieved in a liquid form through the DRI. 

C. Weed abatement - Weeds are a by-product of excessive surface watering. 

D. Pest abatement - Insects and rodents are attracted to the food and water source provided by surface watering.

 E. Clogged emitters - Some vineyards and orchards are replacing thousands of drip emitters a year because of mineralization clogging due to evaporation. This form of calcification clogging does not happen with DRI because the DRI unit seals off the air flow from the drip emitter, therefore preventing evaporation. Minerals in the water remain soluble and pass through the emitter and DRI into the ground becoming food for the plant.

 F. Fungus - Fungus thrives in areas of high humidity. The use of DRI can represent considerable savings in the cost of fungicide and savings of crops lost to fungus related problems. By using DRI you eliminate high humidity caused by surface irrigation and evaporation. 

G. Fertilizers - With DRI, you should see a significant reduction in use of fertilizers because with DRI, fertilizers are being delivered directly to the root zone, instead of being displaced on the ground surface and lost to evaporation and run off. 

4. How long does DRI last in the ground?

The DRI units are made from materials that have been used in the irrigation industry for decades. Reports from the manufacturers of the soaker hose used for the DRI state that soaker hose installed in sub-surface irrigation in the mid 1990’s is still operating at full flow rate today. 

5. Will DRI clog?

 DRI manufacturers are in their 7th year of field testing the DRI units. Regular inspections for possible clogging due to sediment back flow, root intrusion, and mineralization build up, have shown no clogging of the DRI unit. 

A. Silt- because of the positive pressure coming from inside the DRI unit from the water supply, silt is constantly pushed away from the pores of the DRI unit.  

B. Calcification - Mineral build up is a by-product of evaporation. The DRI unit is not affected by evaporation because it is sealed off from air flow. 

C. Root Intrusion - At the point from which water is released from the supply tube inside the DRI unit, there is a copper element which acts as a root deterrent for capillary roots. Copper screening has long been used as a root control for roots from bamboo and other invasive landscape plants.

6. Is DRI pressure compensating? Do I need to use pressure compensating emitters?

The DRI unit needs to be attached to a pressure compensating emitter when pressure compensation is necessary, like on hillside planting and long runs of irrigation hose where the friction coefficient is a factor.

7. How many DRI should I use?

We recommend using one DRI unit per vine in the vineyard and two per tree in orchards. One DRI unit per tree is recommended for saplings. Consult your arborist for large heritage trees which may require more than a couple units per tree. Some larger orchard trees like walnuts may also require more than 2 units per tree. Consult your crop advisor on that.

8. With sprinklers and drip irrigation I see water, but how do I know if DRI is working? 

You should see a 4 to 6 inch wet spot where the quarter inch tube of the DRI enters the ground. 

9. What if I don’t see the wet spot on top of the ground during irrigation? 

If you don’t see the wet spot, check first to make sure the top of the soaker hose is buried about 3 inches below the surface of the ground. Then check to make sure you’ve closed the hole where the DRI unit enters the ground. This is important to ensure necessary compaction that will cause the water to build up pressure to rise to the surface.

If that doesn’t work, check you emitter to make sure water is flowing. It is likely that if water is not flowing you have a clogged emitter. Flag emitters can be cleaned out individually while others may need to be replaced. Your main line may need to be flushed. 

In sandy soils you may need to replace your emitters with those that have a greater flow rate.

10. Can I fertilize through the DRI unit? 

Yes, you can run any liquid through the DRI that you can run through your emitter.

11. How will the DRI system affect evapotranspiration monitoring? 

If the intent of evapotranspiration monitoring is to assess how much water the plant, tree or vine needs, then DRI will provide a more realistic reading because there will no longer be the ambiguity caused by the evaporation of excessive surface watering.

12. What size emitter should I use? 

This will depend on your soil type. Heavier clay soils require a slower flowing emitter like a half gallon or one gallon per hour emitter. The more porous and sandy soils will use 2 to 4 gallon per hour emitters. The objective is to have complete saturation at the root zone and still see that 4 to 6 inch wet spot on the ground which tells you that the DRI is working. If the wet spot is gets too excessive too quickly, it means you’re putting water in the ground faster than the ground can absorb it. In which case, you need to reduce to an emitter with a slower rate of flow.

13. Can I just use a coupler instead of a flow regulating emitter to connect my DRI unit to the irrigation supply line?

No, in all soil types you need to regulate flow otherwise you will create excessive, uncontrolled flow resulting in too much water being lost by perking to the surface.

14. Is DRI compatible with my micro sprinklers? 

Yes, a lot of growers are turning to DRI as their only method of irrigation but are keeping their micro sprinklers to use for winter season frost control.

15. If I use DRI, will I need to change my irrigation cycle?

You might need to reduce irrigation frequency. We have found a high probability that heavier soil types, when irrigated with DRI, hold water for a longer period of time than they did with surface drip.

16. Can DRI be used to control salt concentration at the root zone? 

Yes, you can run fresh water through the DRI to flush the salt concentration from the root zone.

17. How is DRI more environmentally friendly than traditional forms of surface irrigation? 

Using DRI reduces energy used to pump water. It significantly reduces water and fertilizer use. DRI dramatically reduces the need for herbicides, pesticides, and fungicides. 

One scientist with whom we spoke was enthusiastic about the idea that using DRI would significantly lessen the nitrous oxide emissions which are a by-product of ground surface fertilizing. Also, that a fertilizer delivered directly to the root zone is less apt to end up in our rivers, streams and lakes. 

It is also important to note that the soaker hose part of DRI is made from recycled tire rubber.

18. I just bought a sulphuric acid machine. Can I run sulphuric acid through DRI? 

Yes, you can run acid through DRI. You can run anything through DRI that you’ve been running through your existing irrigation system.

19. Now that I’m using DRI, do I need to change my existing emitters for a different flow rate?

No. But you will want to change your irrigation cycle as you are no longer watering non-essential areas around your plants that you once were. This is because DRI delivers immediately to the root zone, you are going to be using far less water and watering for shorter duration’s.

To determine your irrigation cycles you can use moisture probes and monitor your desired levels. Another way to verify your desired saturation is to run a test with DRI in the soil type independent of your trees or vines. Once the 4-6 inch wet spot begins expanding to 8-10 inches dig down into the soil with a backhoe to observe the subsurface saturation profile. This will give you a good picture of your satiation bulb for a particular watering period.

20. Can I reuse the DRI units? 

Yes, just irrigate an hour or so before pulling the DRI unit up in order to moisten the soil around it, and then it should pull up just like a carrot.

21. DRI claims to promote downward root growth. How do I know that’s what I want? 

From an engineering standpoint, a deeper root system makes for a stronger tree or vine structurally. In the right conditions, trees and vines will create both a downward growing and lateral root structure. But roots tend to grow towards water, and if the water is coming from the surface of the ground, the roots will be more inclined to grow towards the surface of the ground. This creates conditions like J-root that make the tree or vine more susceptible to disease. A tree or vine with a deeper root, like those that are dry farmed will be less vulnerable to disease and more drought resistant.

22. How is DRI different from other forms of subsurface irrigation? 

There have been many attempts by growers and irrigation manufacturers to increase water penetration to the root zone. Buried inline emitters is one way growers have attempted to increase water penetration. They bury the lines 6 to 8 inches below the surface of the ground. This can’t be done in mature orchards and vineyards without damaging existing root structures because they’d be trenching through a mature root system. Also, buried inline emitters are prone to clog and there’s no way of knowing whether the system is working. 

Growers have also run the drip tubing into perforated p.v.c pipe which they’ve inserted into the ground. But this method actually accelerates evaporation at those points of water delivery. 

Also, manufacturers have made products with subsurface delivery vaguely similar to the concept of DRI, but these products are more labor intensive to install and are 7 to 15 times more expensive.

23. How do I install a DRI unit? 

On the average we can install one DRI in about 30 seconds, using a simple tool with a 3/4 inch thick steel rod. This tool was adapted from a 4 foot long foundation stake that could be bought at any lumber yard. After making a hole about 22 inches deep we insert DRI into the hole until the top of the soaker hose is buried 3 inches below the surface of the ground. The 1/4 inch tubing that extends up from the ground is then attached to the existing “woodpecker style” or flag emitter. Try to avoid large loops in your 1/4 inch tubing that can easily be caught with tools. It’s important to remember to compact dirt into the hole where the DRI unit was inserted into the ground.

24. How much does a DRI unit cost? 

The DRI units vary in price based on size and quantities purchased.

25. How should I store the DRI units? 

We actually prefer you don’t store them. We prefer to deliver them to you when you’re ready to install them. If you need to store DRI units for a period of time, please store the DRI units in a cool shaded area. DO NOT LEAVE THEM EXPOSED TO SUN OR EXTREME HEAT SUCH AS IN A VEHICLE OR THE BED OF A TRUCK. SUN AND HEAT WILL DAMAGE DRI. Once installed underground the DRI units will last indefinitely.

26. Can I use DRI with my inline emitters? 

No. You will need to replace the inline hose with standard hard wall hose and install Woodpecker type or flag emitters.

27. What size DRI should I use? 

The DRI-3 is recommended for potted plants and tomato plants etc.

The DRI-6 is recommended for all shrubs and bushes.

The DRI-12 is recommended for all vines and tree crops.

The DRI-18 is recommended for large Heritage type or landscape shade trees.

28. Will using DRI affect my pumps? 

No. The DRI system uses the same principles of physics as buried drip. Like any other form of subsurface irrigation farmers have not found the need to change or re-calibrate their pumps. Nor have they experienced damage to their pumps.

29. Are there any special considerations for installing DRI on a hillside? 

We recommend installing the DRI units to promote more water flow to the uphill side of the tree or vine.