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Retention of 15 N‐Labeled Fertilizer in an Illinois Prairie Soil with Winter Rye
Author(s) -
Blesh J.,
Drinkwater L. E.
Publication year - 2014
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2013.09.0403
Subject(s) - agronomy , cover crop , secale , fertilizer , mollisol , growing season , biomass (ecology) , environmental science , vicia villosa , crop rotation , crop , chemistry , biology , soil water , soil science
Human production of reactive nitrogen (N), particularly for agriculture, has led to consequences for air and water pollution. Winter annual cover crops show promise for reducing N losses from grain agroecosystems. We applied 15 N‐labeled ammonium sulfate at corn ( Zea mays L.) planting in May 2009 to a long‐term corn and soybean ( Glycine max [L.] Merr.) variety trial on an Illinois Mollisol. We tracked the fate of the labeled fertilizer in treatments comparing winter rye ( Secale cereal ) cover to the typical winter bare fallow (BF). We measured fertilizer recovery in corn at harvest in the fall, in rye biomass the following spring (May 2010), and in a range of heterogeneous soil organic matter (SOM) pools at both sampling dates. In the spring, total recovery of added 15 N in crops and soil was low (37–45%). Due to unfavorable conditions for cover crop (CC) establishment and an unusually rainy October, rye growth missed the optimal window for 15 N recovery and little tracer 15 N was recovered in the rye. However, the CC significantly reduced soil inorganic N (SIN) pools in the spring (11.1 kg N ha ‐1 in the BF treatment compared with 1.9 kg N ha ‐1 in the CC treatment) by an amount similar in magnitude to total N uptake by rye biomass (23.7 kg N ha ‐1 ), suggesting that a key role of CCs is scavenging inorganic N mineralized from SOM pools. This study reflected current challenges for incorporating CCs into grain rotations with corn varieties that have longer growing seasons.