Crop residue incorporation alters soil nitrous oxide emissions during freeze—thaw cycles
2013
Pelster, David E. | Chantigny, Martin H. | Rochette, Philippe | Angers, Denis A. | Laganière, Jérôme | Zebarth, Bernie | Goyer, Claudia
Pelster, D. E., Chantigny, M. H., Rochette, P., Angers, D. A., Laganière, J., Zebarth, B. and Goyer, C. 2013. Crop residue incorporation alters soil nitrous oxide emissions during freeze-thaw cycles. Can. J. Soil Sci. 93: 415-425. Freeze-thaw (FT) cycles stimulate soil nitrogen (N) and carbon (C) mineralization, which may induce nitrous oxide (N₂O) emissions. We examined how soybean (Glycine max L.) and corn (Zea mays L.) residue incorporation affect N₂O emissions from high C content (35 g kg⁻¹) silty clay and low C content (19 g kg⁻¹) sandy loam soils over eight 10-d FT cycles, as a function of three temperature treatments [constant at +1°C (unfrozen control), +1 to -3°C (moderate FT), or +1 to -7°C (extreme FT)]. In unamended soils, N₂O emissions were stimulated by FT, and were the highest with extreme FT. This was attributed to the increased NO₃ availability measured under FT. Application of mature crop residues (C:N ratios of 75 for soybean and 130 for corn) caused rapid N immobilization, attenuating FT-induced N₂O emissions in the silty clay. In the sandy loam, residue addition also induced immobilization of soil mineral N. However, N₂O emissions under moderate FT were higher with than without crop residues, likely because N₂O production in this low-C sandy loam was stimulated by C addition in the early phase of incubation. We conclude that FT-induced N₂O emissions could be reduced through incorporation of mature crop residues and the subsequent immobilization of mineral N, especially in C-rich soils.
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