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Brassica Cover Crop Effects on Nitrogen Availability and Oat and Corn Yield
Author(s) -
Gieske Miriam F.,
Ackroyd Victoria J.,
Baas Dean G.,
Mutch Dale R.,
Wyse Donald L.,
Durgan Beverly R.
Publication year - 2016
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2015.0119
Subject(s) - brassica , raphanus , agronomy , white mustard , rapeseed , cover crop , brassica rapa , avena , crop , biomass (ecology) , canola , biology , growing season
Cover crops are used to scavenge residual soil nitrate, with the goal of reducing N losses from agricultural fields and increasing subsequent N availability. Two experiments were conducted to determine fall‐planted brassica cover crops’ effect on N availability for rotational crops. The first evaluated five species—brown mustard [ Brassica juncea (L.) Czern], hybrid turnip ( Brassica rapa L. × B. napus L.), radish ( Raphanus sativus L.), rapeseed ( Brassica napus L.), and white mustard ( Sinapis alba L.)—in rotation with oat ( Avena sativa L.). The second evaluated radish in rotation with corn ( Zea mays L.). End of season cover crop biomass averaged 1160 to 6170 kg ha −1 across experiments, locations, and years. Biomass did not differ by species. Nitrogen accumulation was generally greater than 70 kg ha −1 (range 31–136 kg ha −1 ). In the subsequent spring and summer, brassica cover crops reduced soil nitrate N levels relative to a no‐cover control by 0 to 132 kg ha −1 . In Exp. 1, all brassicas reduced oat N accumulation by ≥77 kg ha −1 and oat biomass by ≥1255 kg ha −1 in June 2012, relative to the control. Mustards reduced oat grain yield by 505 kg ha −1 in 2011, while radish increased oat yield by ≥578 kg ha −1 in each year. In Exp. 2, radish did not affect corn V8 biomass N concentration, grain yield, or response to N fertilizer. Nitrogen taken up by brassica cover crops often is not available when the subsequent crop needs it.