Fall-applied anhydrous strategy
By Steve Fairchild

Getting nitrogen application out of the way before spring can let you focus on planting. But use best practices to make your application last.

Whether fall application of anhydrous ammonia is a good idea depends on whom you ask. An economist will look at historic fall nitrogen prices and point out that an autumn buy usually beats the spring demand spike, resulting in costs savings. An agronomist might tell you there are some extra risks involved. An extraordinarily warm winter or extra wet spring can launch nitrogen into the atmosphere or leach it too deep into the soil for plants to use, erasing any purchase-point savings. And everyone involved will tell you to make sure nitrogen use is environmentally sound. So, as with any farming decision, you have to weigh the options when figuring fall nitrogen into your row-crop plans.

“The truth is that there is a difference between economics and agronomics,” said Dr. Paul Tracy, director of agronomy for MFA. “Growers face a complex series of decisions to make as they decide how to approach the next growing season. Economics has to fit in, as do agronomics. Fall fertilizer is a lock-in to next year’s crop rotation. And it’s a big investment.”

A big investment, indeed. At press time, anhydrous ammonia had reached $0.35 per unit, and no retail can say with certainty what will happen by spring.

And there is another reality: increasingly, producers need to cover more acres with fall anhydrous to manage a spring workload and get corn planted in timely manner. The importance of getting corn in early was evident across the Midwest this spring. While early corn was subject to sporadic replant, many corn acres that missed the first good-weather window suffered planting delays and subsequent yield loss. Early planted corn made better use of the growing season’s available water and had a better chance at pollinating outside the stress of severe heat.

Time shift
In one sense, fall-applied fertilizer is time shifting. Labor performed in the off-season saves time during the hectic spring. That’s true not only for the grower, but also for the supplier of fertilizer. In the case of anhydrous ammonia, keeping a ready supply to the end user has become a complex process in recent years.

“With more corn, larger tillage equipment, more federal regulations and tougher transportation logistics, getting anhydrous ammonia to the country retailer is a challenge,” said Charlie Cott, MFA vice president, Plant Food and Transportation. “Of course, you need to consider the agronomics of your plan, but one thing we look at from the supply side is that farmers can help themselves by helping us spread supply pressure.”

Cott said that when the rush is on to deliver anhydrous in spring, MFA truckers can wait in line at the terminal to load even before they start a multiple-hour delivery to a retail location. Longer truck time means a driver might make only one delivery per day. At high season, with growers driving bigger tractors and pulling larger toolbars, it can be a challenge to keep anhydrous tanks full.

A contributing factor to the more difficult delivery logistics is a shrinking availability of railroads to agriculture. Aside from a general lack of modern cars capable of delivering anhydrous and reluctance to meet common-carrier obligations, carriers have increased prices for rail delivery to mitigate the liability they face for hauling hazardous material.

“We’ve seen this trend coming,” said Cott. “And we’ve dealt with it the best we can. We have five additional trucks and trailers on lease for the coming season. We’re committed to keeping the toolbars running regardless, but it’s more challenging with pent-up demand,” he said.

Aside from over-the-road shipping challenges, a true rush on anhydrous can bring other delivery problems.

“It doesn’t happen often,” said Cott, “but we have seen diminished pressure in the pipeline that feeds our delivery points.”

Originating in the Gulf of Mexico, the pipeline has multiple loading facilities as it travels north. Under the strong draw of an application rush, it becomes a soaker hose—pressure relieved along the line reduces pressure toward the end.

Benefits of fall-applied anhydrous
Fall-purchased anhydrous is typically less expensive than buying during the spring rush. While it’s difficult to pinpoint exact numbers, USDA historic fertilizer data show that fall-purchased nitrogen was a good buy through the 80s to the mid-90s, when the fall/spring comparison ended. However, the volatility of current energy markets combined with potential swings in corn acres has the pricing system topsy-turvy. So keep in mind, just like the stock market, it is important to realize that past performance is no guarantee of future results. As you well understand from recent nitrogen purchases, current energy prices can send price shocks through the system. Moreover, we now face a period of increased volatility. In the past, anhydrous ammonia prices could be reliably pegged to the price of natural gas, but as we’ve seen in the past year, consolidation in nitrogen manufactures seems to have affected that price paradigm.

Thus, the modern-day strategy for your farm is to consider your time constraints in spring and the cost savings you might achieve with a fall nitrogen buy versus potential nitrogen loss in spring and the overall efficiency of your nitrogen program.

The big wait
Favorable conditions for tillage in early autumn aren’t necessarily an invitation for fall nitrogen application. Cliff Snyder, the nitrogen program director for the International Plant Nutrition Institute, reports that in corn country, “It is critically important to delay fall applications until the average daily soil temperatures at 4 to 6 inches (measured mid-morning) reach 50 degrees or below.”

While farmers aren’t interested in losing nitrogen from fields, growers in most of MFA’s trade territory farm on soils that rate in the low- to mid-discharge levels for nitrogen according to the USGS. The exceptions are the loess hills of extreme northwest Missouri and soils throughout much of the Bootheel. Snyder pointed out that growers shouldn’t push nitrogen application on soils likely to leach, including coarse-textured or excessively well-drained soils.

Cool soil temperatures might not come as quickly as you think. According to a University of Missouri weather station in Albany, Mo., 6-inch soil temperatures on soybean stubble averaged 46 degrees in November the past several years. In 2005 and 2006, November started with soil temperatures below 50 degrees and stayed that way. But in 2004, the 6-inch soil temperature didn’t fall below 50 degrees until Nov. 20.

For most Missouri corn farmers, the 6-inch soil temperature is available here: http://agebb.missouri.edu/weather/reports/soysoil6.asp.  

If you farm in the Bootheel, visit http://agebb.missouri.edu/weather/stations/. University of Missouri Bootheel weather stations have soil temperature readings, but not yet at the 6-inch depth. You can get customized weather reports that include soil temperatures via e-mail at http://agebb.missouri.edu/horizonpoint/index.asp.

These real-time soil temperatures will give a non-emotional “go” time for fall nitrogen application.

For the MFA trade territory’s climate range, a nitrification inhibitor like nitrapyrin (N-Serve) is a necessary investment for fall application of anhydrous ammonia. But like nitrogen, N-Serve efficacy is determined by when it is applied and soil temperature. With soil temperatures remaining below 50 degrees, N-Serve can last up to 5 months.

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