Valley Irrigation Field Days | by Shannon Peterson

Waste water center pivot discussion

August 26 Field Day at Fair Oaks Farms

Valley_® Irrigation just hosted the second of this summer’s three Field Days welcoming international visitors. 

Each year, Valley hosts hundreds of international visitors who travel to the United States to learn about this country’s farm practices. The guests are interested in touring farms, Valley dealerships, and the Valley Irrigation factory. This year we decided to step up our efforts and turn these events into world-class educational events. 

Each Field Day includes industry leading representatives from Valley, local universities, Nelson^® Irrigation, and Senninger^®. 

The first Field Day, in late July at Taylor Farms in Ames, NE, focused on corn and soybeans. The most recent Field Day – Monday at Fair Oaks Dairy in Fair Oaks, IN – had a slightly different twist: waste water management.

In addition to learning about center pivot irrigation equipment, irrigation technology, water application technology, and crop management, our recent guests—from Brazil, Uruguay, Argentina, Slovakia, Poland, Russia, and other countries—witnessed first-hand how an Indiana dairy recycles the manure of 15,000 cows. 

Simply put: the cows’ waste is used to grow the crops the cows eat. 

The manure is broken down, mixed with water and applied via Valley center pivots onto the crops used to feed the cows. No other fertilizer is needed because of the abundance of nutrients in the manure. It’s a complete, efficient sustainable system.

Naturally, the process is far more complex than outlined here. But as we approached a center pivot and saw brown water emitting from the sprinklers and end gun, the simplicity and, dare I say, “beauty” of the system generated exclamations in multiple languages.

The brown water also had us exchanging looks that crossed any language barriers. Wide-eyed looks that said, “What is this going to smell like?”

Our final Field Day, on September 9 in Grand Island, will offer insight on potatoes grown in Nebraska and sold to national potato chip makers. That should make for entirely different experience, and smell.

For more information on our final Field Day, and to register, visit www.valleyirrigation.com/FD2013.

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Shannon Peterson Marketing Content Editor Shannon joined Valley Irrigation in 2013. She enjoys traveling with her family, particularly to national parks, and she occasionally writes about her travels for Home & Away magazine. Shannon also likes reading, trying new restaurants, seeing movies, and watching Husker football and Creighton basketball. However, she and her husband spend most of their free time chauffeuring their teenage son to activities and chasing their baby daughter.

Irrigation Soil Types: Part II | by Travis Yeik

In "Irrigation Soil Types: Part I," we discussed how to manage water applications on variable soil types in the same field. We concluded that soils with lower available water holding capacity (AWC) didn’t necessarily need more water, but needed water more frequently than soils with higher AWC. 

If you have heard news about how Variable Rate Irrigation (VRI) technology can improve irrigation efficiency and increase crop productivity by applying water site-specifically to different parts of the field based on varying soil types, you may be wondering how that is possible. If, in general, crops use water at the same rate regardless of the soil type they are grown in, how does VRI justify that soil types need watered differently? The answer to this question deals with how irrigation scheduling is managed. 

Using VRI, the general approach is to supply necessary amounts of water to the sandy soils because, as discussed earlier, these soils will show first signs of crop stress; while at the same time, applying less water to heavier soils having higher AWC because of their greater ability to store and supply plant available water. This approach can be effective because heavier soils will not reach their minimal allowable depletion, or MAD (typically around 50% of field capacity), as soon as the soils with lower AWC. 

Table 1 (below) summarizes a VRI scenario with two soils (clay and sand) at different AWCs. At field capacity, a clay soils can hold 1.90 inches of water/foot of soil, whereas sandy soils can hold 0.80 inches of water/foot of soil. Therefore, if we have a corn (maize) crop with a root zone of 3 feet, the available water at field capacity (as shown on Day 1 in the table) in clay soils will be 5.70 inches and 2.40 inches in sandy soils per root zone. Corn, at full coverage, may consume water (also known as evapotranspiration [ET], or the combination of evaporation and transpiration) at a rate of 0.32 inches per day in a moderately hot climate. By Day 5, sandy soils will have reached the MAD, which requires irrigation in order to reduce the risk of crop-water stress. Therefore, water was applied to the sandy soil at a depth of 1.25 inches, which increased the available water to the plant (column 6) up to 85% (note: it is not watered up to 100% of field capacity in order to allow room for precipitation). Conversely, only 0.63 inches of water, or half of what was applied to the sandy soil, was applied to the clay soil, which brought its available water up to 83% of field capacity. This irrigation scheduling was then repeated on Day 9 and again on Day 13. Finally, on Day 16, over two weeks later, the clay soil reaches its MAD when it is at 49% of field capacity. 

Table 1. Irrigation schedule of a sandy soil and a clayey soil using VRI.

In the irrigation scheduling example described above, both soils would have the same amount of water applied to them if they had been filled back up to field capacity. The only thing that changed is the irrigation rate: sandy soils were watered at twice the irrigation depth of the clay soils. So how does VRI help improve water efficiency and increase crop productivity? 

Water efficiency can be improved by two ways. First, it is possible to reduce runoff and deep percolation caused by heavy rainfall during this two week period. Under uniform irrigation management (Table 2, below), the clay soils remains between 75-100% of field capacity and never reaches the MAD. The example in Table 2 shows what would happen if a rainfall event of 1 inch occurred on Day 11 of the irrigation schedule. If this happened, both the clay and the sand soil would become saturated, which would cause runoff and deep percolation, resulting in a loss of 0.6 inches of water. However, with the VRI system, a rainfall event of over 1.95 inches would be needed before the clay soils become fully saturated on Day 11. 

Table 2. Irrigation schedule of a sandy soil and a clayey soil using uniform irrigation management. On Day 11, a precipitation event added 1 inch of water to the field, causing saturation in both soil types

Secondly, water efficiency can be improved by reducing runoff caused by limited infiltration rates in heavier or compacted soils. By applying less water periodically to clay soils, we can be assured that our infiltration rate will not be exceeded. This decreases the amount of ponding occurring on heavier soil types, which can then help increase crop productivity in these areas. 

There are a multitude of other benefits resulting from using VRI to target variable soil types. Because we are actually applying less water to our clay soils with every pass, the pivot will speed-up over sectors of the field with less than our base application rate (which, as explained earlier, is targeted toward the soils with the lower AWC). This will then result in faster pivot revolutions, which will enable the pivot to make it around more quickly in order to water those soils with lower AWC more frequently. 

There are many factors that influence the amount of water taken from a unit of soil by a plant. If we look into each one of these factors, we will realize that water is not actually taken out equally in all soils. For instance, different soil types have different cation exchange capacities, which regulate the amount of readily available nutrients to plants. Therefore, plants may be growing more vigorously in heavy soils because there are more nutrients readily available. This will cause differences in plant growth, maturity, and leaf area, which in turn affects the amount of water crops transpire. So, VRI can actually water site-specifically toward these areas with different crop-water use requirements. 

Variable Rate Irrigation isn’t just a package of hardware and/or software incorporated with a center pivot; it requires accurate irrigation scheduling, soil mapping, and decision support.

For more information on VRI, visit valleyirrigation.com.

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Travis Yeik Variable Rate Irrigation Agronomist Travis joined Valley Irrigation in February 2013 after completing his graduate degree at the University of Nebraska - Lincoln. His work focuses on writing prescriptions for the Valley VRI products. As a native of Wyoming, Travis enjoys outdoor activities, including fly fishing and hiking. He also enjoys sports and is looking forward to baseball season.

VRI Provides Impressive ROI

Originally published in PivotPoint Summer 2013.

Soil and topography can vary drastically within each field, making precise, uniform irrigation very challenging, even with the best irrigation equipment. Valley_® Variable Rate Irrigation (VRI) allows growers to increase yields by using water more efficiently.

“It’s an easy way to increase profitability,” says Valley VRI Product Manager Cole Fredrick. “Growers can look at their field data and make adjustments as often as they need to. When used properly, the return on investment should be very fast – between one and three years.”

Growers Take Control

Patented Valley VRI allows growers to adjust the watering rate in a particular sector or management zone.

Based on an uploaded VRI Prescription, VRI Speed Control increases or decreases the speed of the pivot itself to provide the desired application depth along each sector.

“Growers can do this with any Pro2 or Select2 control panel, with a simple software upgrade,” explains Fredrick. “The sprinkler packages don’t require any change at all. TrackerPro or TrackerLT remote communication devices allow growers to use VRI Speed Control with a Valley Classic or ClassicPlus control panel, too – or even with a non-Valley machine.”

VRI Zone Control uses an uploaded prescription, too, but the sprinkler valves pulse along specified pivot zones to reach the right application depth within a management zone. This is perfect for pivots that go over ditches, canals, wet areas, roads, or other obstacles.

For Zone Control, a Pro2 panel and other hardware is required to control individual sprinkler banks for precise water application.

Valley VRI software helps growers and/or their Valley dealer create a VRI Prescription based on topography, soil data maps, yield data, and other user-defined field information. The QuickStart (QS) Prescription for Speed Control is custom-designed for individual fields. It can be uploaded onto new machines, so the grower can start using VRI benefits as soon it is installed, or the QS Prescription can upload to any existing VRI-Ready machines.

Saving Water and Energy

In a 2010 Kansas field study, using VRI significantly educed field variability, and light-textured soils yielded well, even in a dry year. Also, 12 percent less irrigation was applied by using the prescription across the field,reducing water and energy use.¹ 

Ahmad Khalilian, agricultural engineer at Clemson’s Edisto Research and Education Center in Blackville, SC, conducted three on-farm test systems using VRI, which he believes will save 1.4 to 2.8 million gallons of water per year. 

“Variable Rate Irrigation also means less energy for pumping, less water runs off the field, and less pollution reaches streams,” Khalilian says.²

“It’s definitely a good, sound investment,” says Fredrick. “I’m telling you, it’s worth it!”


For more information on Variable Rate Irrigation (VRI) from Valley, visit www.valleyirrigation.com.

¹ Variable Rate Irrigation 2010 Field Results for Center Plains Conference. Jacob L. LaRue, Valmont Irrigation. http://www.ksre.ksu.edu/irrigate/OOW/P11/Larue11.pdf.

² Variable rate irrigation reduces water use, Impacts Magazine, Tom Lollis, Copyright © 2013 Clemson University, Clemson, SC. All Rights Reserved. Clemson University, Clemson, SC 29634, Tel (864) 656-3311.

Irrigation Soil Types: Part I | by Travis Yeik

Soils are a leaky bucket of water. Even though rain and precipitation continually fill up the bucket, leaks are a result of evaporation, transpiration, runoff, and deep percolation (Figure 1). As more water is added to a soil, more water will be readily available to the plant; however, the downside to adding more water is that our bucket becomes leakier as well. For example, a saturated soil will have greater potential for runoff and deep percolation than a soil at field capacity. Maximum water loss from transpiration occurs between field capacity and the permanent wilting point. Soil water management aims to reduce leaks in our bucket, while, at the same time, providing adequate water to our crops.

The amount of water in our bucket, or available water holding capacity (AWC), depends on soil type and depth of the root zone. The AWC depends on two soil properties: the colloidal content (or amount of clay and humus) and the pore size/structure of a soil. A sandy soil, which typically has less colloidal content and larger pore sizes, won’t have an AWC as large as silts or clays per unit volume of soil (Figure 2). Because sandy soils cannot hold as much water as silt or clay soils, these areas will be the first to show signs of crop water stress.

A common misconception is that we can just add more water to the sandy soils to prevent crops from showing signs of water stress as quickly. However, as noted earlier, too much water added to a soil results in excess runoff and deep percolation. In fact, healthy plants if we consider equal crop types, growth stages, and other growth factors use water at the same rate regardless of what soil type they are grown in. Thus, a sandy soil which has a smaller bucket doesn’t need more water, but simply needs to be watered more frequently than other soil types.

Consider the example shown in Figure 3. At field capacity, clay soils can hold 1.9 inches of water/1 foot of soil, whereas sandy soils can hold 0.8 inches of water/1 foot of soil. Therefore, if we have a corn (maize) crop with a root zone of 3 feet, the available water at field capacity in clay soils will be 5.7 inches, but 2.4 inches in sandy soils. Corn may consume water (also known as evapotranspiration [ET], or the combination of evaporation and transpiration) at a rate of 0.32 inches per day in a moderately hot climate. This will result in an ET of 0.96 inches over a three-day time period. At that rate, clay soils lose 17 percent of its available water compared to sands, which will lose 40 percent of its available water!

In order to effectively manage irrigation in a field with various soil types, the amount and timing of water applied should be targeted to the soils with the lowest AWC.

Figure 1. Illustration of a soil profile as a leaky bucket. Soil water inputs are a direct result of irrigation and precipitation, whereas soil water losses occur from evaporation, transpiration, runoff, and deep percolation. Field capacity is represented as the lid of the bucket, where each addition of water will result in increased runoff or deep percolation. The permanent wilting point is represented as the bottom of the bucket.

Figure 2. Representative “clay” bucket (at top) and “sand” bucket (at bottom). The clay bucket has a larger volume than the sand bucket, meaning it has a larger AWC and can store larger amounts of water per unit volume.

Figure 3. A clay soil, which can hold 5.7 inches of water per 3 feet of soil, and a sandy soil, which can hold 2.4 inches of water per 3 feet of soil, will lose water through crop use (ET) at the same rate. However, because sand has a smaller bucket, it will reach its depletion point much sooner than the clay bucket.

Stay tuned for Part II of the irrigation soil types blog series, coming later this week!

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Travis Yeik Variable Rate Irrigation Agronomist Travis joined Valley Irrigation in February 2013 after completing his graduate degree at the University of Nebraska - Lincoln. His work focuses on writing prescriptions for the Valley VRI products. As a native of Wyoming, Travis enjoys outdoor activities, including fly fishing and hiking. He also enjoys sports and is looking forward to baseball season.

Large Dairy Becomes Huge Attraction

Originally published in PivotPoint summer 2013

Register TODAY for a FREE Valley Field Day at Fair Oaks Farms on Monday, August 26! Visit www.valleyirrigation.com/FD2013 for more information and to register!

Fair Oaks Farms

On Interstate 65, between Chicago and Indianapolis sits an unlikely tourist attraction – a working dairy with about thirty thousand head of cattle and twenty thousand acres of cropland. Fair Oaks Farms has become a destination for schoolchildren and families to learn about the source of their food – especially milk, cheese and ice cream – by creating the Fair Oaks Dairyland Adventure.

“People don’t know where their food comes from,” says Robert den Dulk, Irrigation and Wastewater Manager. “One of the goals of Fair Oaks Farms it to educate the public about that.”

“It’s one of the largest dairies in the United States,” explains Valley Territory Manager, Dave McAlpin. “They have done a really great job of marketing to the public. On any given day, there are six to eight school buses in the parking lot. The kids can learn how cows digest food, watch them being milked, and even see calves being born.”

About 80 calves are born every day at Fair Oaks Farms. With so many mouths to feed, they grow corn, beans, alfalfa, and wheat, most of which is used to feed their own cattle.

In fact, Fair Oaks Farms is as self-sufficient as a farm can be, with a closed-loop system. Their land produces the food for the cattle. The cattle produce – along with the necessary milk for their dairy products – waste and methane. The methane goes to digesters that aid in creating the electricity for the farm and fuel for their trucks. The waste goes into the wastewater management system that, in turn, provides nutrients for the land.

21 pivots are tied in to their wastewater system. “Everything we can get to with our pipes is tied in, because we don’t have to add any other nutrients when we have our fresh and wastewater mixed.

“We’ve got 31 pivots and two linears on our crops, all managed under a Valley BaseStation” says den Dulk. “We use BaseStation every day to make sure we know what our machines are doing and to be able to address the specific machines that need attention on a timely basis.”

Ralph Mercier, owner of Mercier Valley, designed the wastewater distribution center for Fair Oaks Farms.
“They have four locations of wastewater ponds, by each dairy,” Mercier explains. “We wanted to tie it all together, even miles away, so we made a central location at the central dairy and incorporated a pump system to get the fresh/wastewater mix to the fields. The longest run is two and a half miles.”

A little more than half of the pivots are tied in to the wastewater distribution center, and den Dulk says there’s no need to fertilize any of those fields beyond that. “We’d like to reach all of the rest of the pivots at some point, but for now they’re just too far away. In the future, we may be able to tie them all in.”

The future is wide open for Fair Oaks Farms. They plan to expand their operation to include pigs, chickens, horses and fish. “We’ve got big expansion plans to keep making it bigger and better,” says den Dulk, “even adding a convention center and water park.”

McAlpin adds, “They do a great job of marketing to the public while running a successful large scale operation. It’s a pretty neat combination.”

The Fair Oaks Dairy Adventure^®

Since its inception, Fair Oaks Farms has made it a goal to educate the public in a unique and fun way – and they do it well. Their Dairy Adventure lets people see and experience sustainable dairy farming, from witnessing the birth of a new calf to touring the dairy to attempting to prep a fiberglass cow for milking in 19 seconds. It’s unusual to find a place that can educate people about silage and host birthday parties for kids! Find out more at www.fofarms.com.

Happy National Farmers’ Market Week | by Shannon Peterson

One of the best things about late summer is the bounty of the harvest. During a recent visit to an Omaha Farmers’ Market, my family and I mingled with an enormous crowd browsing booths bursting with brightly colored produce, vibrant flower arrangements, local meats, and artisan cheeses. It was a pleasure to be in the midst of the city, but enveloped by the smells of fresh-picked dill, moist soil, and pungent green onions.

This particular market has grown over its two decades from a few overpriced veggie vendors to a Saturday morning destination featuring street musicians, bakery goods, and crafts along with the season’s freshest, locally grown (and reasonably priced) produce.

This week is National Farmers’ Market Week – a time to celebrate the growers that provide the endless variety of food options we have in the United States. The growing farm-to-table and eat-local movements, as well as the passionate desire of people to learn about where their food comes from, have spurred tremendous growth in farmers’ markets across the country. This year, 8,144 markets are listed in the U.S. Department of Agriculture’s National Farmers’ Market Directory - an increase from about 5,000 in 2008.

The markets also are to be commended for reaching out to those most in need of fresh foods in their diets. Vendors are providing locally grown vegetables and fruits to low-income senior citizens, women, and children by accepting payment through government assistance programs. And often leftover goods are donated to food banks. How cool is that?

Meanwhile, I dragged my family down each row scoping out what was available and comparing prices. As I purchased cucumbers (two for 50 cents), the friendly young vendor told me to grab an extra one, illustrating the connections built between customers and growers throughout the season. Regular customers purchase from preferred vendors week after week and inadvertently learn about the farms and the families that nurture them.

In fact, I bought sweet corn from the Wenninghoff’s Farm booth and learned the family sells vegetables daily at its farm store near the edge of Omaha. I often drive past the farm, which uses several Valley® center pivots in its fields, and next time I’ll be stopping to check out the store.

I invite you to celebrate National Farmers’ Market week by visiting your local market. Whether you try a new vegetable, pick up your tried-and-true favorites, or treat yourself a bouquet of sunflowers, you’ll be supporting and honoring the growers that make it all possible.

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Shannon Peterson Marketing Content Editor Shannon joined Valley Irrigation in 2013. She enjoys traveling with her family, particularly to national parks, and she occasionally writes about her travels for Home & Away magazine. Shannon also likes reading, trying new restaurants, seeing movies, and watching Husker football and Creighton basketball. However, she and her husband spend most of their free time chauffeuring their teenage son to activities and chasing their baby daughter.

Irrigating with End Guns | by Jerry Gerdes

We are midway through the summer, and as I drive through the country, I see many center pivot machines hard at work applying water to growers' crops. It's impressive to see how crops in pivot-irrigated fields perform so much better than the crops without irrigation!

Not too long ago, I came across an article about a center pivot end gun irrigating the road beside the field (to read the article, click here), so I thought this would be a good opportunity to write about end guns and this issue, which has come up more than once in my career.

Many center pivots have a large sprinkler, commonly referred to as an end gun, installed at the very end to irrigate field areas beyond the end of the center pivot structure. An end gun is a cost-effective option for irrigating an additional 80’ – 100’ of field area, increasing the productivity of a center pivot. Controls are required to turn the end gun on and off, preventing it from irrigating areas outside of the field boundary. These controls consist of a valve at the end of the machine and mechanical or electronic controls at the center of the pivot machine that control the end gun by pivot angle position.

End Gun

A few times during my travels, I have run across road areas that have been watered by the end gun, indicating that the controls were not working properly. This can create hazardous driving conditions for motorists. There are two items you can inspect to make sure your end gun controls are working properly: the end gun valve at the end of the machine and the angle position settings at the center pivot control panel. These should be checked periodically throughout the irrigation season. Proper control of an end gun will ensure efficient use of irrigation water and safety for everyone traveling the roadways.

For more maintenance tips for your center pivots and linears, check out valleyirrigation.com. 

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Jerry Gerdes Product Manager - Water Application Jerry, Nebraska-based Water Application Product Manager, contributes years of experience from his time working for a sprinkler manufacturer prior to joining Valley Irrigation. Currently working with different sprinkler manufacturers, Jerry develops the recommendations for the optimum water application package for a grower's operation.