Soil sample timing, nitrogen fertilization, and incubation length influence anaerobic potentially mineralizable nitrogen

Authors

Jason Clark, South Dakota State UniversityFollow
Kristen S. Veum, USDA, Agricultural Research Service
Fabián G. Fernández, University of Minnesota - St. Paul
Newell R. Kitchen, USDA, Agricultural Research ServiceFollow
James J. Camberato, Purdue University
Paul Carter, Independent Agronomist
Richard Ferguson, University of Nebraska-LincolnFollow
David W. Franzen, North Dakota State University
Daniel E. Kaiser, University of Minnesota - St. Paul
Carrie A. M. Laboski, University of Wisconsin - Madison
Emerson Nafziger, University of IllinoisFollow
Carl J. Rosen, University of Minnesota, St. PaulFollow
John E. Sawyer, Iowa State University
John F. Shanahan, Soil Health Institute, Lincoln

ORCID IDs

https://orcid.org/0000-0001-7793-6411

https://orcid.org/0000-0002-6492-913X

https://orcid.org/0000-0002-8478-701X

https://orcid.org/0000-0003-4080-9616

Document Type

Article

Date of this Version

2020

Citation

Soil Sci. Soc. Am. J. 2020;84:627–637.

DOI: 10.1002/saj2.20050

Comments

2020 The Authors.

Abstract

Understanding the variables that affect the anaerobic potentially mineralizable N (PMNan) test should lead to a standard procedure of sample collection and incubation length, improving PMNan as a tool in corn (Zea mays L.) N management. We evaluated the effect of soil sample timing (preplant and V5 corn development stage [V5]), N fertilization (0 and 180 kg ha−1) and incubation length (7, 14, and 28 d) on PMNan (0–30 cm) across a range of soil properties and weather conditions. Soil sample timing, N fertilization, and incubation length affected PMNan differently based on soil and weather conditions. Preplant vs. V5 PMNan tended to be greater at sites that received < 183 mm of precipitation or < 359 growing degree-days (GDD) between preplant and V5, or had soil C/N ratios > 9.7:1; otherwise, V5 PMNan tended to be greater than preplant PMNan. The PMNan tended to be greater in unfertilized vs. fertilized soil in sites with clay content > 9.5%, total C < 24.2 g kg−1, soil organic matter (SOM) < 3.9 g kg−1, or C to N ratios < 11.0:1; otherwise, PMNan tended to be greater in fertilized vs. unfertilized soil. Longer incubation lengths increased PMNan at all sites regardless of sampling methods. Since PMNan is sensitive to many factors (sample timing, N fertilization, incubation length, soil properties, and weather conditions), it is important to follow a consistent protocol to compare PMNan among sites and potentially use PMNan to improve corn N management.