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

March 4, 1999

NDSU Soil Scientist: Don't Let Emotions Rule Fertilizer Decisions

Difficult economic times make many people, including farmers, cautious. But while caution can serve as an instinctive defense mechanism, it also functions as an emotion. And when it comes to 1999 fertilizer strategies, a soil scientist at North Dakota State University says producers should be basing their decisions on solid information, not feelings and emotions.

"Soil testing and the use of qualified crop consultants are not just for good times," says Dave Franzen, soil specialist with the NDSU Extension Service. "Too many growers cut back on these necessities at the first sign of economic hardship, often with tragic results."

Strategic fertilizer mistakes can occur in several ways: applying unneeded inputs, making unnecessary applications or mis-timing applications. Some growers try to cut corners by having a consultant scout one field and then extrapolate that information to other fields, but this strategy assumes all fields will be affected by similar pests and soil conditionsan assumption which is usually wrong.

"In some cases, a mistake on just one field could pay for the annual services of a consultant for an entire farm," Franzen stresses.

While producers should test each field, they might need to test some fields differently, Franzen says. If history indicates that composite soil testing is unreliable, using landscape relationships (hilltops, slopes and depressions) can help pinpoint field fertility levels.

Consider the Crop
Nitrogen is necessary for each crop, but decisions regarding whether to implement an aggressive or a conservative strategy based on NDSU fertilization guides will vary with each crop. Factors influencing N management include crop-quality concerns and crop susceptibility to disease from excessive fertilization. Phosphorus is necessary for most crops, Franzen says, but soil levels and the amount required for individual crops vary.

"Study the NDSU recommendation charts to determine whether cuts are prudent. Other nutrients are highly specific for certain crops," Franzen says.

Canola is the only crop in North Dakota with an exceptional requirement for sulfur. The sulfur source should be in sulfate form to ensure highest yields. Use of other sources may lead to lower yields and lower profits, Franzen says.

Chloride treatments on wheat and barley have produced responses, but mainly on soils testing less than 30 pounds/acre and only on certain cultivars, Franzen says.

NDSU researchers also have observed chloride responses in corn, but not in other crops. Only four cropscorn, dry beans, flax and potatoeshave a special sensitivity to zinc. In addition, researchers have identified copper deficiency in North Dakota on wheat in 1998, but a response to copper occurred at only one site, which had sandy soil with a low organic matter content.

Which Strategy? Aggressive? Conservative?
In an aggressive approach producers set high yield goals and pad normal recommendations to allow accumulation of protein, such as in wheat. Franzen says, "Since protein premiums have not been exciting recently and given the abysmal prices of late, growers may choose to select a more realistic yield goal as a basis for N recommendations. If a 45-bushel yield is relatively easy to attain, choose that as your goal, not some figure that you've hit only once in 10 years or so."

Soils with higher organic matter are more forgiving than those with lower organic matter levels. So, a conservative approach to N management in some fields may still result in higher yields in a year with above-normal rainfall, since mineralization of organic matter is higher under moister conditions, Franzen explains, but protein percentages might suffer with this approach.

Crops that should normally receive conservative fertilizer treatments are malting barley and sugarbeet, due to quality concerns resulting from excessive N. Dry beans fertilization should also be conservative to avoid excessive vegetation and prevent white mold in some years, Franzen says.

Avoid Miracle Products
Advertising claims for products containing biological activators that release "locked-up" nutrients and eliminate the need for fertilizer are unfounded, Franzen says. The following statements represent red flags signaling buyers to beware.

• It activates soil microorganisms.
• You can replace your normal fertilizer program with just a few quarts of product.
• It contains a lot of different micronutrients.
• It takes care of alkali spots.
• It contains blue-green algae, fungi or fish extracts.
• It works on all soils and all crops.
• It contains humates.
• It makes soil hold water better and dries up wet spots.
• It takes care of cloddy conditions.

"Growers who are curious about products making these types of claims should test them first on a small acreage," Franzen concludes. "Don't select a spot near your house or a feedlot because soil nutrients are seldom needed where there has been a history of manure application."

###

Source: Dave Franzen (701) 231-8884

Editor: Dean Hulse (701) 231-6136