NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

March 23, 2000

News Is Good for Nitrogen Prices, Nitrate Conversion; Options Similar to Last Year

Nitrogen (N) fertilizers remain relatively low in price despite recent increases in gasoline and diesel fuel prices. One reason for the current price scenario is oversupply, says a soil scientist at North Dakota State University. Until the supply situation reverses, buyers--namely farmers--can expect bargains.

"Transportation costs for moving N fertilizers will probably have some impact on the retail price of fertilizers, but the cost of the fertilizers themselves will be stable through spring," says Dave Franzen, extension soil science specialist at NDSU. "The industry people I have talked to see no change in the supply condition until crop prices improve and farmers become more aggressive in their purchases."

But will farmers necessarily purchase more fertilizer then? Franzen says the relationship between crops prices and N fertilizer sales seems to create a paradox: Farmers tend to use N fertilizers more efficiently when crop prices fall, so even when crop prices rebound, there is less demand due to the efficiencies producers have achieved.

More Good News

"Between the fall of 1999 and mid-March 2000, there has been lower-than-normal snowfall and rain in the state," Franzen says. "This is good, because the warmer weather has most likely contributed to higher nitrate conversion on those acres where N fertilizer was applied. If precipitation this spring is normal, or below normal, crops should be able to make full use of fall-applied N."

Franzen says N fertilizer options for 2000 are similar to last year, and in many locations, producers have better options due to the drier seedbed conditions. The following application guidelines are based on reports and observations of soil conditions around the state:

• Anhydrous ammonia--Anhydrous ammonia can be applied before seeding in a separate trip across the field or at the time of seeding if a special boot is rigged so that ammonia does not contact the seed. When seeding and fertilizing separately, the fertilizer direction should be at an angle to the seeding direction. Ammonia moves 2 to 3 inches in all directions away from the point of application, even if it is applied as a liquid using a "cold-flo" converter, so if the ammonia is applied at 5 inches or shallower, some seed contact is inevitable. Planting at an angle reduces the number of plants that will be affected by the ammonia band. When fertilizing at seeding, the boot should place the ammonia at least 3 inches laterally from the edge of the seed pattern. One common problem in light, fluffy dry soils and cloddy soils is placing the ammonia too close to the surface. If the ammonia is placed 3 inches or less from the surface, significant losses of ammonia through volatilization are possible. Placement 4 inches or deeper is a better option. Keep safety in mind when handling ammonia by making sure supplies of fresh water, gloves and goggles (unvented) are within easy reach on tanks.
• Urea--Warm temperatures, residue levels, soil moisture, wind speed, relative humidity and the time interval after application are all important following a urea application. Urea placed on the soil surface undergoes soil enzyme transformation to free ammonia and carbon dioxide, which may result in the loss of a large portion of N if not incorporated by rainfall or a tillage operation. Placement under the soil surface takes care of this concern. Many growers apply urea at seeding with a planter boot that separates the fertilizer from the seed. Separation by at least 1 inch is necessary to avoid seed damage. Other growers apply urea in a separate trip 2 to 3 inches below the seeding zone. Many more growers broadcast urea and either incorporate it with tillage or count on precipitation to move the urea into the soil. Generally, with soil temperatures cooler than 50 F, cloudy days, calm winds and dry conditions, urea can remain on the soil surface for five to seven days with little loss--but these ideal conditions are rare. Warmer planting-time soil conditions, breezy winds, a little dew in the morning and some residue cover can convert substantial amounts of urea to ammonia in just a few days. It is safest to plan tillage within two days. If application is made to no-till fields, harrowing is better than doing nothing, although the soil needs to be loose for harrowing to cover any pellets. Use of a urease inhibitor can give growers another 10 days of safety before the fertilizer needs to be incorporated. A urease inhibitor has an additional cost, but so does N loss.
• Ammonium sulfate--Growers with low sulfur soil test levels in areas of the state registering high amounts of rainfall last year may want to consider a sulfur application for small grains this spring. There are several sources of sulfur available, but those with immediately available sulfur are preferable over those that must rely on "sleepy" soil microorganisms for transformation to sulfate. Growers considering a sulfur application should look first to coarser-textured hilltops and eroded slopes because those are areas most likely to need sulfur due to leaching. The N in ammonium sulfate has some volatility potential, but the sulfur does not. Sulfur can sit on the soil surface a long time with no losses. If ammonium sulfate remains on the soil surface for several weeks without rain, a few pounds of N will be lost, particularly in high pH soils, but these losses are probably not worth an extra tillage.
• Manures--Manures should be incorporated as soon as possible. Manures contain some free ammonia that is available to crops if incorporated. Also, as manure decomposes additional ammonia may be produced and lost through volatilization. Manure application should be made as evenly as possible. This is often not practical to expect on many farms, but livestock/crop farmers who develop a viable means of producing compost will benefit from a high-quality, highly spreadable manure. Compost has excellent fertilizer properties and can be spread at most any rate with a spinner spreader for accurate and even application.
• Legumes and Previous Crop Credits--Remember to take previous crop credits when following legumes or sugarbeets. These residues release N early in the growing season. The amount of credits to take can be found in the NDSU Extension Service publication titled "North Dakota Fertilizer Recommendation Tables and Equations Based on Soil Test Levels and Yield Goals" (SF-882), which is available from county extension agents or via the Internet (http://www.ext.nodak.edu/extpubs/soilfert.htm).
• Application of N with the Seed--Although there is a tradition of applying fertilizer with small grain seed at planting, there are limits to how much fertilizer can be placed with the seed. Fertilizer contains high levels of salt and may contain materials that produce free ammonia, both of which are harmful to seed germination. All current publications from the NDSU Extension Service on wheat, canola, field peas and lentils, and soybeans, as well as publications on other crops, contain guidelines regarding crop tolerance and performance when fertilizer is applied with the seed. These publications are also available from county extension agents and via the Internet (http://www.ext.nodak.edu/extpubs/soilfert.htm).

###

Source: Dave Franzen (701) 231-8884
Editor: Dean Hulse (701) 231-6136