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ARS Home » Midwest Area » Columbia, Missouri » Cropping Systems and Water Quality Research » Research » Publications at this Location » Publication #332585
Title: Can the anaerobic potentially mineralizable nitrogen test improve predictions of fertilizer nitrogen rates in the Cornbelt?

Author
item CLARK, J - University Of Minnesota
item Veum, Kristen
item FERNANDEZ, F - University Of Minnesota
item CAMBERATO, J - Purdue University
item CARTER, P - Dupont Pioneer Hi-Bred
item FERGUSON, R - University Of Nebraska
item FRANZEN, D - North Dakota State University
item Kitchen, Newell
item LABOSKI, C.A.M. - University Of Wisconsin
item NAFZIGER, E - University Of Illinois
item SAWYER, J - Iowa State University
item SHANAHAN, J - Dupont Pioneer Hi-Bred

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/30/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Correctly estimating the amount of mineralizable nitrogen (N) can enhance nitrogen use efficiency. The anaerobic potentially mineralizable nitrogen (PMNAn) test is a tool that may help improve predictions of N uptake, grain yield, and the economical optimum nitrogen rate (EONR) of corn (Zea mays L.). A 30 site-year study across eight US Midwestern states was conducted to quantify PMNAn across various soils and regions and to determine the influence of soil sampling timing, N fertilizer, and laboratory incubation lengths (7, 14, and 28 days) on improving the PMNAn correlation with N uptake, grain yield, and EONR. Soil was sampled from 0-30 cm before planting and N fertilizer application (PPNT) or at the V5 leaf stage where 0 (V50) or 179 kg-N/ha (V5-179) were applied at planting. Overall, PMNAn ranged from 0.19 to 136 mg/kg with a mean of 36 mg/kg. Mean PMNAn for coarse, medium and fine textured soils were 22, 34, and 45 mg/kg, respectively. This indicates greater potential for mineralization with finer textured soils, which in general had greater organic matter content. There was no consistent pattern in PMNAn with time of sampling. The PMNAn was larger in ten site-years at PPNT and nine site-years at V50, with no difference in the other eleven site-years. There was also no consistent pattern in response to the addition of N fertilizer. The V5-179 PMNAn was lower than the V50 in ten site-years, greater in one site-year, and no different in 19 site-years. All sites increased in PMNAn as laboratory incubation length increased. Preliminary results for the PPNT 7 day incubation indicate that for each 1 mg/kg increase in PMNAn the EONR was reduced 1 kg-N/ha. Additional results of the correlations between PMNAn and N uptake, grain yield, and EONR will also be discussed.