Application Timing Important to Fertilizer Impact

REGINA - Mar 8/04 - SNS -- Timing seems to be more important than how fertilizer is applied, suggests results of a three-year project that compared the agronomic performance, energy use and nitrous oxide emissions from a variety of nitrogen fertilizer managements at four different soil-climatic zones in Saskatchewan.

For example, Bourgault mid row band and Flexi-Coil Stealth side band seeding systems were used to compare the merits of mid row band and side band systems when used on wheat, canola and flax crops. Urea and anhydrous ammonia were the nitrogen sources and 11-51-0 was the phosphate source.

"Overall, there were no grain yield differences between the systems 84% of the time. Where there were differences, there was an almost even split between the systems," says Gordon Hultgreen, manager, Soils and Crops, Prairie Agricultural Machinery Institute (PAMI) at Humboldt. "Similarly, placement of nitrogen in the side band or mid row band position had little effect on wheat protein.

Hultgen says 40% of Saskatchewan's seeded acreage is now direct-seeded, with both mid row and side band systems being popular with farmers. "So we're happy to report that the agronomic results of both are excellent."

Collaborating with PAMI on the project The Effect of Nitrogen Fertilizer Placement, Formulation, Timing and Rate on Greenhouse Gas Emissions and Agronomic Performance was the University of Saskatchewan, as well as Agriculture and Agri-Food Canada (AAFC) research stations at Scott, Melfort, Indian Head and Swift Current.

Dr. Reynald Lemke is a research scientist at the latter, and he says it's important to note that the spring application of urea and anhydrous ammonia at all sites was at three different rates: recommended, half the recommended, and one and a half times the recommended rate based on soil tests.

"The use of these different application rates adds to the confidence we have in our results," he explains.

Lemke also points out various findings that were not totally new but confirmed previous research: for example, fall-banded nitrogen and broadcasted urea tended to be less efficient than their spring-banded counterparts.

"And sometimes the results of the project were most interesting for what we didn't see: for example, conventional wisdom has it that anhydrous ammonia is not effective in the Swift Current area, but our results showed that anhydrous ammonia is equal to urea in this area. We didn't see any difference," says Lemke.

The project also compared net energy returns of crops fertilized with urea and anhydrous ammonia. Net energy returns were generally higher for anhydrous ammonia because energy costs - the fossil fuel used in production and transportation - of anhydrous ammonia is less than urea, and there was little difference in crop response to the two forms of nitrogen.

Emissions of nitrous oxide, one of the most important greenhouse gases, were studied as well. It was concluded that nitrous oxide emissions from urea and anhydrous ammonia are similar.

"In general, however, results from this study indicate that nitrous oxide emissions are comparatively low from well-managed cropping systems in Western Canada. So we suggest that the specific nitrogen fertilizer system -side-row versus mid-row, and anhydrous ammonia versus urea - is of less consequence than ensuring the optimal use of nitrogen fertilizer additions. In short, when the nitrogen fertilizer inputs are matched with the crop needs, nitrous oxide emissions are minimized," says Lemke.

The project The Effect of Nitrogen Fertilizer Placement, Formulation, Timing and Rate on Greenhouse Gas Emissions and Agronomic Performance, #19990028, was supported by the Agriculture Development Fund. A copy of the final report is available by phoning 306-787-5929 in Regina. The final report is also available on the Saskatchewan Agriculture, Food and Rural Revitalization Web site. A summary of the report is available on the PAMI Web site at www.pami.ca under "Research Update #761: Mid Row or Side Band?"

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