Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/1997
Publication Date: N/A
Technical Abstract: A N-fertilizer decision aid was evaluated on five farms in southwestern MN. Farmers performed usual practices with the exception of N-fertilization on an 8 to 12-row strip running the entire length of a corn field. Soil samples were taken to a depth of 60-cm by taxonomic classification and examined using the preplant and pre-sidedress nitrate tests. A N-fertilizer decision aid was used to predict the amounts of nitrate produced from planting to the V-5 growth stage of maize. Nitrogen fertilizer was then applied to each taxonomic unit to bring the soil test values to 20 ug g**-1. Changes in nitrate between the two samples ranged from -6.4 to 11.7 ug g**-1 with a mean of 2.52 +/- 4.18 ug g**-1. The predicted change in nitrate ranged from -0.25 to 10.7 ug g**-1 with a mean of 2.31 +/- 2.14 ug g**-1. At harvest, duplicate grain samples were taken from the test strip and the adjacent area. Using the decision aid, a median Aid:Producer grain yield ratio of 1.04 (ns; p > 0.05) was obtained with about 7% less applied fertilizer N.