Rising nitrogen fertilizer costs have growers ready to start planting (in Washington state next week and western Idaho and eastern Oregon in three more weeks) wondering how they can handle them.
Compared with last fall, Idaho retailers are paying as much as 20 percent more for dry nitrogen and 30 percent more for liquid, Bryan Hopkins, University of Idaho extension potato cropping system specialist, said.
While Hopkins is hopeful the prices will drop as summer approaches, the price increases are troublesome. He says the cost of making nitrogen fertilizer has been rising steeply with the cost of natural gas which is used in its manufacture.
Hopkins says there is a Univeristy of Idaho on-line publication written by Hopkins and colleagues Jason Ellsworth and Paul Patterson which outlines strategies growers can implement. It also explains how to calculate economically optimum amounts of nitrogen.
Entitled, "Skyrocketing Nitrogen Prices and Potato Production," the publication describes how to measure residual nitrogen carried over from last year, how to project nitrogen needs based on anticipated yields, and how to adjust that computation downward based on other potential sources of nitrogen--including pesticide carriers, starter fertiliers, irrigaton water, manure, previous legumes, and crop residues.
It can be read at:
http://www.ag.uidaho.edu/aers. Select Resources, Department Publications and the 2003 Extension series. A companion site gives growers the cultural requirements of several varieties of potatoes, including Bannock, Gem and Ranger Russet. See: http://info.ag.uidaho.edu/potato.