Imagine a field where every drop of water applied to a crop goes right to the root zone of the crop – minimal water wasted to evaporation or drain-off from the land, greater yields per acre of land, and better quality of crop produced.
Drip irrigation makes this a reality for growers. Not only does a good drip irrigation system enhance water use efficiency (WUE) and uniformity, it also offers the potential for greater resource use efficiency (RUE), resulting in more crop per drop (of water, that is).
Once it has been decided to convert a field to drip, growers can choose to work with a trusted irrigation company to design the system. While a good company will ask several questions to ensure the system is designed to meet each grower’s unique needs, it’s equally important growers know the right questions to ask of the company. Here are 11 important questions every grower should ask a drip irrigation designer.
Find the Right Partner
Before the design process even begins, a grower needs to find the right company partner to design the drip irrigation system. Watch to learn more about what to expect from a good irrigation design partner and the benefits of RDO Water’s custom irrigation design.
Below are three important questions to ask right off the bat and a company that can answer “yes” to all is the difference in overall satisfaction and full ROI potential vs. dissatisfaction and inability to achieve maximum ROI.
Question: Do you offer a thorough consult to ensure an ideal, customized drip irrigation system is recommended?
Question: Do you install the drip irrigation system?
Question: Do you provide ongoing service and support?
Existing Field Conditions
Once the right irrigation partner is found, growers should focus initial questions to the irrigation designer. These first questions should focus on the grower’s present situation; things that have an impact on the system and that would be difficult to modify once the system is in place.
Question: How will the drip irrigation system affect my crop rotation schedule?
Imagine the proposed field is primarily a vegetable crop field but will be rotated to berries in the future. A good designer will ensure the system is designed to support desired crop rotations. Single-season drip tape designs are a newer route and one that makes it even easier to rotate the crops, as new emitters and spacing can be specified each season and crop rotation. RDO Water, for example, offers services related to single-use drip tape which is encouraging more growers to go this route with irrigation.
Question: Do I need to change block size?
A good designer will evaluate and determine ideal block size for the system, taking into account factors like crop ET, soil type and water availability. Strawberries are an example of one crop that may warrant smaller blocks, to ensure the water is staying concentrated enough to meet needs, and without pushing the system to or beyond its maximum. There has also been a trend on the coast to switch to growing in substrate, where block size is even smaller, often as small as two acres per block vs. the typical 15-20.
Drip systems are accommodating to various sizes, though they work best in smaller blocks and with various block shapes. They’re great for growers with irregularly-shaped fields and corners that are challenging for traditional irrigation systems like pivot.
Question: How does my soil type affect emitters?
Soil type is an important design parameter with regard to the drip system’s emitter flow (low flow vs high flow). Loamy or clay soil better holds water, so a low-flow emitter is sufficient compared to sandy soils that require a higher flow emitter to accommodate more rapid water percolation and poorer lateral dispersion.
Question: Speaking of spacing, how is lateral spacing determined?
Soil type/texture affects not only the emitter flow rate, it is also a primary determinant for emitter spacing. A soil that encourages lateral spread of water (clay/loam) can have emitters spaced further apart vs. porous soil that holds water loosely. Sandy and porous soils require close spacing, medium loam soil require medium spacing, and heavy, silt/clay loam soil farther apart.
Changing an irrigation system will no doubt affect a farm’s day-to-day operations. To be prepared and set up for success, every grower should ask questions about the changes to expect.
Question: How do I control irrigation periods with the new drip irrigation system?
There are several options for controlling irrigation periods with a drip system. A grower may choose pulse irrigation, where the system is run for short periods of time every day to apply the daily required amount of water. Another option is running the system every few days, for a longer time-period, applying multiple days-worth of water in a single day.
Automation systems are a great option to consider; because they allow growers to set irrigation periods, they can result in significant time and labor savings. The benefits are typically realized sooner and on a greater scale in larger operations vs. small.
With that in mind, automation systems present more considerations for smaller growers. For example, a smaller farm, one with five blocks or fewer, an automation system may not be needed or provide enough value to justify the cost. Every grower should analyze the cost/benefit ratio to decide if it makes sense for his/her unique operation.
Question: Does the drip irrigation system affect my fertilizer use?
All growers must run chemicals through the drip lines to prevent emitter clogging. Virtually all must filter their water, too in order to prevent clogging. If fertilizer is used in the drip system, it should be injected upstream of the filter station.
Operations that use highly-acidic fertilizers will require corrosion resistant pipe, typically PVC or poly, as acid can corrode steel or aluminum pipe. If a grower negates to ask this question upfront, a good designer will ask about fertilizer early-on in the process so there shouldn’t be any need for revisions after the system is installed.
Growers who mix fertilizers should seek information and training on the topic to prevent solid precipitation and other unanticipated side effects. Some mixes, combined with rain, can lead to emitter plugging if not managed properly.
Question: Will this new drip irrigation system affect harvest?
One of the biggest benefits of a drip irrigation system is uniformity of water application for plant growth.
A grower using flood irrigated alfalfa has an expectation of approximately 6 to 8 cuts per year. However, a grower using drip-irrigated alfalfa can expect 10 to 12 cuts per year. The drip-irrigated alfalfa also produces a higher quality crop at the time of harvest.
This isn’t exclusive to alfalfa; virtually all other irrigated crops may benefit from the plants having more uniform growth.
Question: How do I properly maintain the drip irrigation system?
When it comes to system maintenance, an integrated, planned approach is advised for all drip systems. A few best practices include:
During the season, periodic flushing is advised every 2-4 weeks to get rid of potentially clogging debris. Periodic filter maintenance is also recommended. Regular inspection of the piping system for leaks is advised to avoid air intake, resulting in water hammers (pressure surges) or air pockets which can have a damaging effect to the system.
Those who re-use drip tape must carefully retrieve it to ensure the equipment isn’t slicing or puncturing the tape. Next, the removed tape must be properly stored, then checked at the beginning of next season to confirm it’s in good shape to use again. If being used for more than one season, a drip tape with greater wall thickness (10mil or 13mil –vs- 6mil) is recommended.
Partnering with an irrigation company that provides service after the sale is a great advantage to growers, as drip systems can be expected to last at least ten years with good care.
Questions to Ask a Drip Irrigation Designer are Important
A good drip irrigation designer will take into account each unique grower, field characteristics, and operation when specifying and installing a drip system. However, it’s important all growers are proactive and ask questions that ensure the right partner is chosen and the process goes smoothly.
About The Author
RDO Water has a staff of five highly trained designed professionals. DuWayne Fritz is the Lead Designer for RDO Water in Yuma, AZ. DuWayne has been designing drip-irrigation systems for 25 years for customers in the Southwest United States and northern Mexico. DuWayne has a degree in engineering and is a certified micro-irrigation designer for the Irrigation Association.