Retention and Turnover of Corn Residue Carbon in Some Eastern Canadian Soils
- B. C. Liang ,
- E. G. Gregorich,
- M. Schnitzer,
- C. M. Monreal,
- A. F. MacKenzie,
- R. P. Voroney and
- R. P. Beyaert
Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, Box 1030, Swift Current, SK, S9H 3X2, Canada
Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, ON, K1A 0C6, Canada
Dep. of Natural Resource Science, Macdonald Campus of McGill Univ., 21111 Lakeshore Rd., Ste. Anne de Bellevue, PQ, H9X 3V9, Canada
Dep. of Land Resource Science, Univ. of Guelph, Guelph, ON, N1G 2W1, Canada
Pest Management Research Centre, Agriculture and Agri-Food Canada, Delhi, ON, N4B 2W9, Canada
Agricultural practices determine the level of soil organic C by influencing the amount of residue returned to, and retained by, soil. We conducted field experiments on four soils in Ontario and Quebec to test the hypothesis that short-term changes in soil organic C and the proportion of corn (Zea mays L.)-residue C retained in soils are affected by soil texture, fertility, and tillage management. We measured the amount of stover to estimate C input into the soils, and total soil C and 13C natural abundance to determine the soil C derived from corn residues. Only the sandy clay loam exhibited changes in total soil C, related to levels of fertilizer N and quantity of residues returned to the soil. The proportion of soil C derived from corn residues varied from 4 to 19%, depending on the time under continuous corn. Our data indicate a rapid increase in the proportion of cornderived C in the early stage of cropping to corn, but a markedly reduced rate of increase beyond 12 yr. Measured δ13C of archived samples of two soils with different clay contents (71 and 28% clay) but similar residue inputs (11 Mg stover ha-1 yr-1) indicated that the rate of increase in the proportion of corn-derived C was higher in the soil with higher clay content (2.4 vs. 1.9% yr-1). The results of this study are consistent with the hypothesis that the quantity of crop residue inputs and soil texture greatly influence the retention and turnover of crop residue C.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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