Onan’s irrigation system pays its way even if wet years outnumber dry ones
Amherst Junction, Wisconsin — Most of Paul Onan’s milking cows are contentedly grazing lush pasture at high noon with the mercury heading toward the upper-90s. It is a scene many a midwestern dairy grazier would pay a lot to duplicate in this terrible summer of 2012.
And Paul has paid more than a little. More than $12,000 for a well and a 10-horsepower submersible pump. Equipment valued at more than $10,000, although most of that cost was covered by a government grant. About $500 worth of electricity used during a period of four weeks, with much more to come should the dry weather continue. Close to an hour’s worth of daily labor to move equipment, plus the usual hassles involved in fixing the broken parts that come with anything mechanical.
All to irrigate about 30 acres, which hasn’t produced enough pasture to avoid having to feed some haylage since July 1 to his more than 90 milking cows along with this year’s calf crop.
Are the returns worth the investment, costs and the labor? “For me, yes, it’s a paying proposition,” Paul answers. That assertion is backed by an analysis included in the aforementioned grant. Tom Kriegl, a farm financial analyst with the University of Wisconsin Center for Dairy Profitability, figures that Paul comes out ahead with irrigation if the system is employed for a lengthy period at least one year out of three.
And here, it most likely will be used at least that often. Paul’s sandy soils dry up in a flash despite nearly 20 years of good grazing management. Pastures not reached by irrigation were dormant in early July despite having received rains into the middle of June. This is irrigation country. Many of Paul’s neighbors are tapping the relatively high water table to irrigate cash crops, and the Golden Sands potato region a few miles to the east has an even higher table and is even more dependent upon irrigation.
Paul says he suffered from dry weather five consecutive years starting in 2005. “Most of those years, we were on full (stored) forage for three or four weeks at mid-summer,” he describes. “That gets expensive.”
But despite a relatively small land base and the local culture, Paul wasn’t ready to invest in irrigation until the local Golden Sands conservation district obtained a two-year Grazing Lands Conservation Initiative (GLCI) grant used to lease two K-Line pod systems and accompanying plastic feeder lines from a local dealer. Paul did have to pay for the well (six-inches in diameter drilled to 103 feet) and pump.
The K-Line standard is 12 irrigation pods at 50-foot intervals, creating a 600-foot surface irrigation line that can be shifted back and forth across the pasture with an ATV or some other low-horsepower machine. Each shift is capable of irrigating three-quarters of an acre in 50-foot strips with 50 pounds per square inch of pressure at the last pod. Paul’s pump creates 100 psi at the well head and is capable of producing 100 gallons per minute. The system was designed to run up to three pod lines at the same time, and Paul was operating all three of his during the height of the dry spell this summer.
The 80 acres of milk cow pasture are divided into four long, narrow strips that are temporarily split with polywire to create 12-hour grazing breaks. Each of these strips has a riser fed by the well near the road, giving Paul the ability to irrigate a total of about 40 acres — essentially the front half of the 80. However, this summer he was putting water on just three of the pastures, with the fourth out of commission until the next substantive rains arrive.
Paul acknowledges that he’s not being the most efficient irrigator. To water the additional 10 acres he could put in a fourth pod line, or even shift one of the current lines. But that has yet to happen.
Also, making only two shifts per day is putting too much water on too small an area: Paul estimates that an inch-and-a-half is being applied to the 0.75-acre strips every 12 hours. Eight-hour shifts would provide a more appropriate amount of moisture while offering the potential to cover more acres with the same number of pod lines. The Golden Sands grant report suggests that six-hour shifts would be even better in terms of spreading investment costs over more acres while still applying enough water, although that analysis noted that such a strategy would require midnight labor.
And the shift pattern here isn’t the most efficient. After the pod line has been shifted across the width of the pasture over the course of seven days, Paul starts back in the opposite direction, arriving where he had begun nearly two weeks earlier. It means that the edges of the pastures are being watered at inconsistent intervals — a reality that was showing up in early July in the form of brown, stunted grass in areas that hadn’t been watered in more than 10 days — a couple of which had seen 100-degree air temperatures.
Paul says there’s at least one major reason for this inefficiency: “Labor is a problem around here.” At age 60, he is running the farm largely by himself after an intern departed last spring.
It’s not easy for Paul to allocate an extra half-hour at a specific time of day to move three pod lines. Also, with the current schedule he is able to shift the lines while the cows are walking to the barn and eating their supplement. He can do the shift at the same time he’s moving the break wire, thus avoiding the need drag 600 feet of plastic piping through standing polywire and posts. Perimeter fences are an even bigger problem in such shifts, which is another reason why Paul isn’t trying to irrigate the fourth paddock with his three lines.
Paul says he’s glad he took out the permanent cross fences that once split the long strips. “We couldn’t do this if we still had the old five-acre paddocks,” he asserts. “With irrigation, fewer fences is better.”
The fact that the cows frequently graze amid the pods is a bit of mixed blessing. It’s a pretty good deal on very hot days, as most of the cows alternate between a cool shower and going out to put their heads down to graze. “They wouldn’t be doing that without the water,” Paul said as the sun bore down. He noted that on a recent 102-degree day, about two-thirds of the herd remained on pasture even though they had access back to the barn. Both milk and solids levels had declined markedly after the first of July, but Paul blamed the inclusion of haylage in the barn ration for much of that.
The down side is that cows are certainly capable of damaging things like plastic fittings. Indeed, one connector with damaged threads had popped off on the morning Graze visited, with water gushing out the end of the line and virtually nothing coming from the pods. Paul says he usually has to fix something about twice a week when the systems are operating.
In reality, the major problem with system breakdowns seems to lie with pulling the lines through tall, lush grass. “There’s a lot of force on these (lines) when they’re being pulled around,” Paul notes. To reduce that force (and to stay dry), Paul doesn’t follow K-Line’s advice that the system be operating while being moved. But that means he has to be extra careful not to kink the empty lines.
The pod system’s limitations include timing of fertilizer applications: Paul waits for rainfall like everyone else due to the reality that some of his acres won’t see water for several days at a time. It’s another reason why a center pivot might be a better system — at least if he could afford the costs of drilling at least a 16-inch well and installing a pump capable of producing at least 5,000 gallons per minute, plus paying for a pivot. And Paul thinks that all irrigation in Wisconsin will someday come at a price beyond the current nominal annual pumping permit.
Despite the limitations that come with pod irrigation, the simple fact of the matter is that it is doing what it’s supposed to be doing on Paul’s farm. In early July the areas being watered were an oasis amid the surrounding area of dormant grass and shriveling corn. His orchardgrass, bluegrass, white and red clover and (in the lower areas) low-alkaloid reed canarygrass were lush, thriving and being grazed well by the herd. (Paul notes that interseeding alfalfa hasn’t worked with his sandy soils, while pure stands tend to die quickly under grazing pressure.)
And at least according to the grant-funded study, the extra forage produced is more than paying for the related fixed and variable costs, including Paul’s extra labor. The trial took place in 2009 and 2010, his first years of irrigation.
Pasture growth was monitored using an electronic version of a rising plate meter. In the dry year of 2009, areas irrigated between July 1 and September 24 produced two dry matter tons of forage during the period, or 1.5 tons more than adjacent, non-irrigated strips.
Everyone involved in the trial acknowledged that irrigation started too late in 2009 because the new system wasn’t operable until mid-summer. Grazing had ceased by June 15 and pastures had gone dormant by the time the pods started working at the beginning of July. Also, no pasture growth was seen during an initial week of attempting to irrigate only at night. Grazing did not begin again until July 20. The 1.5 tons of extra pasture attributed to the additional water was thus considered a very conservative number.
The trial viewed the extra forage as being equal to 150 RFV hay, and thus valued it at $150/ton. This was compared to ownership costs (amortized over a 20-year period) and the costs of operating the system. In 2009 Paul was using only two pod lines and covering 20 acres with twice-daily moves. Ownership was figured at $107/acre and operating charges at $82/acre. The value of the extra feed grown with irrigation was pegged at $258 (the hay cost was tied to 1.725 tons as fed, equaling 1.5 tons dry matter), producing a net return of $69 per acre.
That might be a very conservative figure. An additional half-ton of forage dry matter likely would have been produced if the irrigation had commenced before drought stress was obvious, the trial report noted. Also, more frequent shifts and additional pod lines would have allowed far more acres to be covered, thus greatly reducing the per-acre investment costs tied to the well and the pump. The report presented scenarios in which per-acre profits might rise above $200.
Then again, irrigation was a money-loser for Paul in 2010, which featured precipitation far above the norm. That year he operated the K-Line for just a few days, incurring some operating expenses with no measurable returns in addition to the fixed costs of owning the infrastructure.
Yet according to Kriegl’s calculations, Paul can have two wet years for every one dry one and still come out ahead with his irrigation system. That’s exactly what he had prior to 2012, as last year also featured a lot of natural precipitation.
Other studies in Wisconsin have suggested that the results of irrigation are not as positive for grazing dairies with heavier soils and deeper water tables. “A lot of this has to do with well depth and the water-holding capacity of your soils,” Paul figures. He thinks that for many graziers, any shot at successful irrigation will depend upon access to drainage ponds, preferably with the ability to recharge naturally.
Pasture irrigation recommendations and precautions
A two-year study of Paul Onan’s pasture irrigation system, funded by the Grazing Lands Conservation Initiative, found that while irrigation seems to pay off on Paul’s farm, that won’t be the case for everyone. Here is a list of findings and recommendations offered by report authors Brian Nischke, Alex Crockford and Tom Kriegl:
1. Inexperienced irrigation managers usually wait too long before starting to irrigate. Waiting too long usually means that some potential yield is lost and the irrigation manager has to play catch-up to avoid losing more yield response.
2. Applying one inch of water per acre per week will use water more efficiently compared to applying two inches of water per acre in one pass for the next 14 days for several reasons. First, some of the irrigation water will likely run off because two inches applied at one time will exceed the water-holding capacity of most soils that will respond to irrigation. Second, more of the moisture in the two-inch application is likely to be evaporated. Third, if adequate rainfall resumes one week after the two inches are applied, a portion of the two inches that was applied would not have been needed. Also, weather forecasts for periods eight to 14 days in the future are less accurate than forecasts in the next seven days. Delivering two inches of water in two passes doubles the labor cost compared to delivering two inches in one pass with the K-Line system. However, labor cost was only about $1.00 per acre-inch in 2009. Therefore, it doesn’t take much gain in efficiency of water use to offset the added labor cost.
3. The operating cost for two acre-inches was $21.25 in 2009. It would only take a dry matter yield increase of 283 lbs. of dry matter valued at $150 per ton to pay for the two inches of water.
4. Increasing yields typically increases the need to add nutrients. This means that more fertilizer will likely be required to consistently achieve higher yields from irrigation over a period of several years.
5. Like any other capital investment, an irrigation system is more likely to pay for itself if used close to full capacity.
6. Ask if irrigation is the best use for your investment dollars. Even if this investment will pay for itself, look to see if there would be another way to invest those dollars for a higher return.
7. This study happened to use the K-Line system. The same economic principles apply regardless of the irrigation equipment or system used.
8. Before investing in an irrigation system, learn as much as you can about the principles of irrigation, the characteristics of your soils, and your micro-climate. With this knowledge, try to project your potential costs and gains before investing. Get estimates of the cost and labor requirements of the irrigation equipment you would use. Your county agricultural agent can help find the information.