Controls of carbon and nitrogen releases during crops’ residue decomposition in the Red River Valley, USA
2020
Chatterjee, Amitava | Acharya, Umesh
Decomposition of crop residue releases nutrients and preserves soil organic matter dynamics. The decomposition rates of six crop residues namely, corn (Zea mays), dry bean (Phaseolus vulgaris), soybean (Glycine max), potato (Solanum tuberosum), sugarbeet (Beta vulgaris) and spring wheat (Triticum aestivum), were studied at three field-sites: Casselton, North Dakota, USA, and Ada and Downer of Minnesota, USA. Litterbags were placed on soil surface on 31 October 2016, and subset was retrieved after 6 months (8 April 2017) and finally after a year (30 October 2017). Crop residue type had significant effect on remaining mass%, carbon (C) and nitrogen (N) release, and C:N ratio. After 1 year, remaining mass% followed the sequence of corn (82%) > soybean (74%) > wheat (72%) > dry bean (55%) > potato (40%) > sugarbeet (17%). Among sites, Ada had higher remaining biomass C and N than Downer but similar to Casselton. Sugarbeet and corn had the highest (0.0054 d⁻¹) and the lowest (0.0005 d⁻¹) decomposition rate, respectively. Decomposition rate had a close relationship with initial residue C:N ratio. Conversion to intensive corn–soybean rotation might increase the residue load on the surface and reduce C and N mineralization loss.
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