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Accueil du site → Doctorat → Canada → The effect of cropping and tillage management on the dynamics of soil organic matter

University of Guelph (1996)

The effect of cropping and tillage management on the dynamics of soil organic matter

Beyaert, Ronald Peter

Titre : The effect of cropping and tillage management on the dynamics of soil organic matter

Auteur : Beyaert, Ronald Peter

Université de soutenance : University of Guelph

Grade : Doctor of Philosophy (PhD) 1996

Résumé
Soil organic matter has been recognized as a key component of sustainable agricultural systems that can be influenced by management practices. A field study was conducted to quantify the changes in crop residue sequestration in continuous corn (Zea mays), winter rye (Secale cerea1e)-flue-cured tobacco (Nicotiana tobaccum) and winter wheat (Triticwn aestivwn)-soybean (Glycine ma.) crop sequences managed under conventional (Cï) and no-tillage (NT) practices in a Fox loarny sand (Brunisolic Gray Brown Luvisol) following a shift in management. Crop yield and total residue carbon production was similar for the two tillage systems for all cropping systems. However, continuous corn produced 1.9 and 1.5 times the amount of residue carbon as the tobacco-winter rye rotation and soybean-winter wheat rotation, respectively, while total residue carbon production was similar for the two crop rotations. Differences in the effects of tillage on residue decomposition resulted in similar amounts of residue carbon remaining in the soil to a depth of 30 cm for the two tillage treatments. The greatest amounts of residue C remaining were found under corn production while the lowest amounts were found under flue-cured tobacco production. Similar amounts of soybean, winter wheat and winter rye residue carbon remained in the soil after 3 years. The accumulation of residue carbon over a 50-year period predicted by an first order exponential mode1 suggested that residue carbon may increase more rapidly in NT systems during the initial 10 years but may decline below those found for conventional tillage practices thereafter, suggesting that reduced tillage does not enhance sequestration of residue-derived carbon. Increases in the residue carbon pool were found when continuous corn cropping was chosen regardless of tillage management and when the l winter wheat-soybean rotation was managed under CT practices compared with the CT rye-tobacco rotation.

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