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The Efficacy of Winter Cover Crops to Stabilize Soil Inorganic Nitrogen after Fall‐Applied Anhydrous Ammonia
Author(s) -
Lacey Corey,
Armstrong Shalamar
Publication year - 2015
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2013.12.0529
Subject(s) - cover crop , tillage , sowing , agronomy , environmental science , conventional tillage , crop , nitrogen , chemistry , biology , organic chemistry
There is a dearth of knowledge on the ability of cover crops to increase the effectiveness of fall‐applied nitrogen (N). The objective of this study was to investigate the efficacy of two cover crop species to stabilize inorganic soil N after a fall application of N. Fall N was applied at a rate of 200 kg N ha −1 into living stands of cereal rye, tillage radish, and a control (no cover crop) at the Illinois State University Research and Teaching Farm in Lexington, Illinois. Cover crops were sampled to determine N uptake, and soil samples were collected in the spring at four depths to 80 cm to determine the distribution of inorganic N within the soil profile. Tillage radish (131.9–226.8 kg ha −1 ) and cereal rye (188.1–249.9 kg ha −1 N) demonstrated the capacity to absorb a minimum of 60 to 80% of the equivalent rate of fall‐applied N, respectively. Fall applying N without cover crops resulted in a greater percentage of soil NO 3 –N (40%) in the 50‐ to 80‐cm depth, compared with only 31 and 27% when tillage radish and cereal rye were present at N application. At planting, tillage radish stabilized an average of 91% of the equivalent rate of fall‐applied N within the 0‐ to 20‐cm, depth compared with 66 and 57% for the cereal rye and control treatments, respectively. This study has demonstrated that fall applying N into a living cover crop stand has the potential to reduce the vulnerability of soil nitrate and to stabilize a greater concentration of inorganic N within the agronomic depths of soil.