ISSUE 1 May 14, 2009
ROW-CROP STARTER PLACEMENT
A 2 inch to the side and 2 inch down from the seed placement (2 by 2; or 2 X 2) in no way inhibits seed germination as does a seed-placed application. The maximum limits on fertilizer applied at planting recommended in our row-crop fertility circulars refers to seed-placed application and not any application (except for anhydrous ammonia) with at least 2 inches separation between the seed and the fertilizer. For a 2 X 2 application, any rate of N plus any other nutrient to at least the limit of our recommendation charts is acceptable if using liquid or dry non-anhydrous ammonia products. For corn, we suggest that when rates of N exceed 50 lb/a in the 2 X 2 band, a separate small P application be made with the seed for a "starter" effect. Since sunflowers and dry beans exhibit no "starter" P response, this extra application is not necessary for those crops.
FERTILIZERS AND FERTILIZER ENHANCEMENT PRODUCTS 2009
The following are comments regarding products or product groups that have been tested in North Dakota recently and are being advertised or marketed within the state.
This product is a maleic-itaconic calcium salt co-polymer that is advertised as having nitrification inhibition and urease inhibition abilities. The theory behind the urease inhibition is that the Nutrisphere-N® (NSN) when impregnated on urea ties up nickel (Ni) ions in the soil thereby rendering urease enzyme (which contains Ni in its structure) inactive. The theory behind its nitrification inhibiting abilities is the complex of copper by the NSN. NSN was tested at several rates along with urea at eight North Dakota locations in 2008 in spring wheat nitrogen rate trials. These trials were conducted near Dickinson, Williston (2), Hazelton, Valley City, Wishek and Langdon (2). Although yield and/or protein/ total grain N uptake was seen at each location with increasing N rates, no additional benefits were seen with similar rates of NSN. In addition, bucket soil samples from similar rates of urea and NSN were analyzed several weeks into the season at two sites to detect differences in ammonium-N and nitrate-N. No differences between urea and NSN in these soils were detected. Laboratory results of nitrification and urease inhibition experiments conducted by Dr. Goos at NDSU during 2008 and published in the North Central Extension-Industry Soil Fertility Conference proceedings from fall, 2008 showed no differences between transformations of urea or NSN. The research at NDSU shows that this is not a beneficial product for our growers in nitrogen management.
Avail is a maleic-itaconic calcium salt co-polymer. It appears that the product is very similar to Nutrisphere-N. The product literature claims to increase phosphate (P) availability through deactivation of ions that normally bind to P and render it less available. Avail has been tested in five site-years of research on sugarbeets at NDSU. A total of 21 treatments of 10-34-0 at various rates plus Avail were compared to 10-34-0 alone at similar rates. Only two of 21 treatments showed a better yield compared to 10-34-0 alone. The rate of benefit is therefore relatively low for the product. At the ratio of benefit and cost of the product, it is difficult to see how a grower might benefit economically from its use.
Slow-release N products
Several slow-release N products are currently being marketed in North Dakota. ESN® is a polymer-coated urea that physically protects the urea from the urease enzyme through separating it from soil. The polymer coating eventually breaks down and allows the urea to be released into the soil. Studies in North Dakota have shown it has particular value under irrigation. However, the physical nature of the coating seems to prevent the N release under dry conditions. ESN use appears to be gravitating towards irrigated acres, which is where it might be best used in our environment of contrasting climates.
Georgia-Pacific’s Nitramin® products (triazone- and methyl-urea)have been tested in wheat and sugarbeet for several years, particularly in spring wheat. The products have shown an efficiency advantage in sandy soils during wet springs, but did not show a yield/protein lag during dry years compared with urea or 28-0-0. This means that products such as Nitramin might find a fit in variable soil fields with problem sandy areas that have potential leaching problems, but are not irrigated. In sugarbeet, the release of some of the N was late enough that some quality problems arose. Later release was not seen as a problem in spring wheat trials.
Some products, such as N-Pact® (26-0-0, with 33% of the N as triazone slow-release N, UAP product) or Coron® (28-0-0, with 70% of the N as polymethylene slow-release N, Helena product) advertise foliar benefits of yield and protein enhancement. NDSU studies using 1-3 g/acre of these slow-release products at various times during the season, including 5-6 leaf, flag-leaf or post-flowering has shown no yield or protein enhancement benefits. The amount of N required for benefits at these growth stages appear to be more than provided in 1-3 g/acre of these products.
Penicillium bilaii- (Jumpstart®/Tagteam®; Novozymes Biologicals)
The fungal ingredient for these products has been around for some time. The claim of the product literature is enhancement of phosphate (P) uptake by crops. The basis for the claim is that the fungus acidifies its immediate soil environment and makes available P that is trapped by carbonate minerals in the soil. Research in North Dakota showed several years ago that if the soil pH is higher than 7 and the soil has significant carbonates then P uptake is enhanced with this fungus. Communications with the original developer of the fungus in Canada relates that about 10 lb P2O5 /acre is made available to crops at best. If pH is lower than 7 and there are no carbonates in the soil, then there is no P benefit to the product.
The problem with the product is that many of North Dakota fields do not have carbonates from fence to fence. In the Valley, most fields have at least inclusions of some size with no carbonates at all and are acid in pH. This product would have no P effect in these soils. In the till plain, there are many fields with widely varying pH levels. Even fields with a composite soil test over 7 would probably have large areas of acid soils. A couple cores from a high carbonate area would easily skew the entire field pH over 7. Along the Missouri River and west there are large areas of mostly acid pH in the state. These products would have no P benefit in these fields. For these reasons, it might be best to apply P fertilizer where needed rather than apply a product that will only benefit certain areas of a field.
NDSU Extension Soil Specialist