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United States Department of Agriculture

Agricultural Research Service


Location: Plant Science Research

Title: Evaluating the accuracy of the presidedress soil nitrogen test when manure is applied during the rotation from alfalfa to corn

item Renier, Robert
item Yost, Matt
item Russelle, Michael
item Coulter, Jeff

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2012
Publication Date: 9/17/2012
Citation: Renier, R., Yost, M., Russelle, M.P., Coulter, J. 2012. Evaluating the accuracy of the presidedress soil nitrogen test when manure is applied during the rotation from alfalfa to corn [abstract]. Proceedings of the 30th Brazilian Meeting of Soil Fertility and Plant Nutrition Conference, September 17-21, 2012, Maceio, Alagoas, Brazil.

Interpretive Summary:

Technical Abstract: Alfalfa has a great capacity to fix nitrogen (N), and it increases the amount of soil N available for the next crop. However, prediction of fertilizer requirement for corn after alfalfa is complicated because N release from organic sources varies with soil temperature and moisture. Furthermore, many producers apply manure to the terminated alfalfa field, which can increase or even decrease the amount of N available during the next growing season. The Pre-Sidedress Nitrogen Test (PSNT) provides early-season information on the amount of N mineralized before the corn crop enters the phase of rapid N accumulation. The objective of this study was to evaluate the accuracy of the PSNT in corn after alfalfa when manure was applied during fall alfalfa termination. Experiments were established in a randomized complete block design with four replications on 10 farms in Minnesota. Treatments consisted of control plots (no fertilizer N) and 45 kg N/ha applied as a sidedressing. Soil nitrate concentration was determined on samples of composited soil cores from the upper 30 cm in each plot. Corn grain yield was determined from hand-harvested samples taken after physiological maturity. Corn yield was not improved by sidedressed fertilizer N except at two of the 10 sites, which produced 1.5 and 2.4 Mg/ha more yield with 45 kg N/ha than with no fertilizer N. However, the PSNT correctly predicted the response or non-response of grain yield to sidedressed fertilizer N at only 4 of 10 farms. The PSNT did not provide reliable predictions of fertilizer N requirement in fields of first-year corn after alfalfa with additional manure N.

Last Modified: 06/25/2017
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