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Is irrigation the answer?

Chad Hale for Progressive Forage Published on 29 April 2019

When asked about how important irrigation was to his operation, Peter Gaul says, “Irrigation is the closest thing to a silver bullet you will find in agriculture.”

Gaul operated Tribute Farms for about 10 years, a grazing dairy in southeast Missouri on very sandy soil. Peter measured the impact of irrigation and determined that irrigation boosted his yields nearly 50 percent. He emphasized that his was not simply a grazing dairy. “We were a grazing and forage-based dairy,” he says.

With the key driver of profit being high-quality and homegrown forage, irrigation was a very easy decision for Gaul. Irrigation ensured two things on his operation: germination and establishment. Those two variables are the biggest risks for growing a crop. With those risks greatly reduced, Peter was able to produce large amounts of high-quality forage primarily for grazing, but also for winter feed. In Figure 1, the difference in forage growth from the same field is apparent.

Shows the difference irrigation makes

Derrick Moot, a professor at Lincoln University in New Zealand, cautions his dryland farmers to think through all variables before installing irrigation. “While production likely will increase, costs will increase as well,” says Moot. He shared some interesting data in Figure 2.

Illustrates the growth tates (overage of two years) of pastures in New Zealand

Compared to the baseline dryland production, producers could get more of a benefit from increased nitrogen fertility than they could from irrigation alone. The biggest increase in production came from irrigation and increased nitrogen application combined. “But that means producers are then dependent on nitrogen,” Moot says.

I have been fortunate to work with producers around the country, and I have been amazed at the unexpected places I have encountered irrigated forages. I currently live in central Washington, where our annual precipitation is 4 to 7 inches, and most of that comes in the winter.

Obviously, irrigation is essential here. I’ll never forget my first visit to Tillamook, an area on the Oregon coast with a number of grazing dairies. It rains 80 inches per year there and in the summer, many of those farmers irrigate! According to Troy Downing, extension dairy specialist for Oregon State University based in Tillamook, irrigation can give those farmers, on average, an extra 25 pounds of forage per acre per day for 120 days. In their case, irrigation gives another ton and a half of dry matter on every irrigated acre, but they only irrigate during the dry summer, not during the whole grazing season.

As with any farming practice, there is no universal answer. As illustrated in the three scenarios mentioned above, some producers wouldn’t be without irrigation, some are better off to invest elsewhere and still others use irrigation on a limited seasonal basis. How can these drastically different viewpoints be explained?

The answer to the question of irrigation depends on many factors. In Gaul’s case in Missouri, irrigation dramatically increased his production. He would have been crippled without it. Meanwhile, in the area of New Zealand studied by Dr. Moot, nitrogen status was more limiting than water, and irrigated land is expensive. And in Tillamook with an abundance of rain, a shortage of moisture in the summer hampers production.

How can you decide if irrigation would be cost-effective for you? Here are some questions that might help you arrive at an answer:

  1. Is water really your limiting factor? Like those farmers in New Zealand illustrated in Figure 2, you might be better off addressing fertility than water.

  2. What is the difference between the cost of irrigated versus nonirrigated land? In Missouri, Gaul discovered the increased cost of irrigated land was minor compared to the greatly increased production. That made irrigated land an attractive capital investment. In your area, it may be cheaper to rent more land rather than improve your own.

  3. What are the differences in yields between irrigated and dryland production in your area? This question will be more difficult to answer in wetter climates where fewer farmers irrigate, but talk to extension people or other farmers. Someone will have an answer; you just have to find them.

  4. How reliable is your supply of irrigation water? This depends heavily on where you live and how regulated water sources are. In severe droughts when irrigation would save the day, you might not have access to water due to your irrigation source being dry or from regulation preventing its use.

  5. How evenly distributed is your rainfall? In the Tillamook example, 80 inches of rain sounds like plenty, but when you consider it hardly rains at all in July and August, there is a period of extreme water deficit where irrigation pays off for many operations.

  6. How long are your dry spells? Much of the Midwest suffers from several so-called “minidroughts” throughout the growing season. These are dry periods that last a week or two. While they do impact forage production, they don’t usually cause catastrophic failures. Investing in an irrigation system to prevent minidroughts may not be profitable.

  7. Can you grow excess forage in times of ample water to stockpile or conserve for times of slower growth? This is the same basic concept as putting up hay for the winter. Stockpiling tall fescue for winter grazing is common in the transition zone. Other parts of the country use a summer stockpile to get through summer drought. Can you grow extra forage in times of ample water and use them in dry periods?

  8. Can your livestock handle lower-quality forage for short periods of time? Most operations outside of dairies or stocker operations can utilize poor-quality forages for a time. Strategic supplementation of abundant but low-quality forage with rumen- degradable protein or scheduling females to be dry during dry weather periods are two ways to counter effects of drought.

  9. And perhaps the question least asked is the most important one: Are you prepared to increase your management to capitalize the increased forage that you would gain from irrigation? As Moot mentioned in New Zealand, the full benefit of irrigation cannot be realized without using more nitrogen in the system. And increased forage availability on a grazing operation will often mean changes to grazing plans and rotations and perhaps more livestock to manage. In addition, there will be an added wrinkle of scheduling pasture rotation with irrigation scheduling. Gaul readily grants that these challenges are real, but he says, “Too much forage is a nice problem to have.”

In the end, your farming philosophy will impact your choice. Irrigated forage production will not be the least-cost option for those who ascribe to that model of production. Farmers who gravitate toward maintaining high production will just need to ensure they can harvest the potential value of their extra forage and not just produce massive tonnage of poor-quality feed that is poorly utilized.  end mark

Chad Hale
  • Chad Hale

  • Research and Acquisitions Manager
  • Western Forage Resources
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