Cost Efficient Tillage and Rotation Options for Mitigating GHG Emissions from Agriculture in Eastern Canada

The economic efficiency of cropping options to mitigate GHG emissions with agriculture in Eastern Canada was analyzed. Data on yield response to tillage (moldboard plow and chisel plow) and six corn based rotations were obtained from a 20-year field experiment in Ontario. Budgets were constructed for each cropping system while GHG emissions were measured for soil carbon and were estimated for nitrous oxide according to IPCC methodology. Complex crop rotations with legumes, such as corn-corn-soybeans-wheat with red clover underseeded, have higher net returns and substantially (more than 1 Mg ha1 year1) lower GHG emissions than continuous corn. Reduced tillage reduces GHG emissions due to lower input use but no sequestration effect could be found in the soil from tillage. Rotation had a much bigger effect on the mitigation potential of GHG emissions than tillage. However, opportunity costs of more than $200 per Mg CO2 eq ha1 year1 indicate the limits to increase the mitigation potential beyond the level of the economic best cropping system.Environmental Economics and Policy,

Cost Efficient Tillage and Rotation Options for Mitigating GHG Emissions from Agriculture in Eastern Canada

The economic efficiency of cropping options to mitigate GHG emissions with agriculture in Eastern Canada was analyzed. Data on yield response to tillage (moldboard plow and chisel plow) and six corn based rotations were obtained from a 20-year field experiment in Ontario. Budgets were constructed for each cropping system while GHG emissions were measured for soil carbon and were estimated for nitrous oxide according to IPCC methodology. Complex crop rotations with legumes, such as corn-corn-soybeans-wheat with red clover underseeded, have higher net returns and substantially (more than 1 Mg ha-1 year-1) lower GHG emissions than continuous corn. Reduced tillage reduces GHG emissions due to lower input use but no sequestration effect could be found in the soil from tillage. Rotation had a much bigger effect on the mitigation potential of GHG emissions than tillage. However, opportunity costs of more than $200 per Mg CO2 eq ha-1 year-1 indicate the limits to increase the mitigation potential beyond the level of the economic best cropping system

Frost Seeding Increases Spring Cereal Yield

Short growing season and mid-summer heat and drought are limiting factors for spring cereal production in Canada, suggesting that higher and more stable yields may be possible if seeding date occurred earlier in the spring. Field trials were conducted in southern Ontario, Canada, in 2003 and 2004 to compare development and yield potential of frost (early April) and conventional (late April â early May) seeded hard red spring wheat (Triticum aestivum L.), spring barley (Hordeum vulgare L.), and oat (Avena sativa L.) established using commercially available no-till planting equipment. Frost seeding had lower plant populations than conventional seeding with pre-tillering plant population reductions for frost seeding averaging 44 pl m-2 (12%) for wheat and 27 pl m-2 (10%) for oats. In spite of lower plant population, frost seeding yields were higher than conventional seeding with yield increases averaging 0.66 Mg ha-1 (24%) for wheat, 0.72 Mg ha-1 (20%) for oats, and 0.36 Mg ha-1 (11%-2004 only) for barley. Frost seeded cereals had earlier occurrence of key phenological stages with average heading dates for frost seeded wheat and barley occurring 5d earlier. Frost seeded cereals also had a longer vegetative period, which along with earlier heading dates, contributed to increased yields for frost seeded cereals.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Increasing Crop Diversity Mitigates Weather Variations and Improves Yield Stability

Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limiting or in excess. Using yield and weather data obtained from a 31-year long term rotation and tillage trial in Ontario, we tested whether crop rotation diversity is associated with greater yield stability when abnormal weather conditions occur. We used parametric and non-parametric approaches to quantify the impact of rotation diversity (monocrop, 2-crops, 3-crops without or with one or two legume cover crops) and tillage (conventional or reduced tillage) on yield probabilities and the benefits of crop diversity under different soil moisture and temperature scenarios. Although the magnitude of rotation benefits varied with crops, weather patterns and tillage, yield stability significantly increased when corn and soybean were integrated into more diverse rotations. Introducing small grains into short corn-soybean rotation was enough to provide substantial benefits on long-term soybean yields and their stability while the effects on corn were mostly associated with the temporal niche provided by small grains for underseeded red clover or alfalfa. Crop diversification strategies increased the probability of harnessing favorable growing conditions while decreasing the risk of crop failure. In hot and dry years, diversification of corn-soybean rotations and reduced tillage increased yield by 7% and 22% for corn and soybean respectively. Given the additional advantages associated with cropping system diversification, such a strategy provides a more comprehensive approach to lowering yield variability and improving the resilience of cropping systems to multiple environmental stresses. This could help to sustain future yield levels in challenging production environments

Improving Resilience of Northern Field Crop Systems Using Inter-Seeded Red Clover: A Review

In light of the environmental challenges ahead, resilience of the most abundant field crop production systems must be improved to guarantee yield stability with more efficient use of nitrogen inputs, soil and water resources. Along with genetic and agronomic innovations, diversification of northern agro-ecosystems using inter-seeded legumes provides further opportunities to improve land management practices that sustain crop yields and their resilience to biotic and abiotic stresses. Benefits of legume cover crops have been known for decades and red clover (Trifolium pratense) is one of the most common and beneficial when frost-seeded under winter wheat in advance of maize in a rotation. However, its use has been declining mostly due to the use of synthetic fertilizers and herbicides, concerns over competition with the main crop and the inability to fully capture red clover benefits due to difficulties in the persistence of uniform stands. In this manuscript, we first review the environmental, agronomic, rotational and economical benefits associated with inter-seeded red clover. Red clover adaptation to a wide array of common wheat-based rotations, its potential to mitigate the effects of land degradation in a changing climate and its integration into sustainable food production systems are discussed. We then identify areas of research with significant potential to impact cropping system profitability and sustainability

Increasing Crop Diversity Mitigates Weather Variations and Improves Yield Stability

<div><p>Cropping sequence diversification provides a systems approach to reduce yield variations and improve resilience to multiple environmental stresses. Yield advantages of more diverse crop rotations and their synergistic effects with reduced tillage are well documented, but few studies have quantified the impact of these management practices on yields and their stability when soil moisture is limiting or in excess. Using yield and weather data obtained from a 31-year long term rotation and tillage trial in Ontario, we tested whether crop rotation diversity is associated with greater yield stability when abnormal weather conditions occur. We used parametric and non-parametric approaches to quantify the impact of rotation diversity (monocrop, 2-crops, 3-crops without or with one or two legume cover crops) and tillage (conventional or reduced tillage) on yield probabilities and the benefits of crop diversity under different soil moisture and temperature scenarios. Although the magnitude of rotation benefits varied with crops, weather patterns and tillage, yield stability significantly increased when corn and soybean were integrated into more diverse rotations. Introducing small grains into short corn-soybean rotation was enough to provide substantial benefits on long-term soybean yields and their stability while the effects on corn were mostly associated with the temporal niche provided by small grains for underseeded red clover or alfalfa. Crop diversification strategies increased the probability of harnessing favorable growing conditions while decreasing the risk of crop failure. In hot and dry years, diversification of corn-soybean rotations and reduced tillage increased yield by 7% and 22% for corn and soybean respectively. Given the additional advantages associated with cropping system diversification, such a strategy provides a more comprehensive approach to lowering yield variability and improving the resilience of cropping systems to multiple environmental stresses. This could help to sustain future yield levels in challenging production environments.</p></div

Corn and soybean mean grain yields per growing season clusters in different tillage systems.

<p>Corn and soybean mean grain yields per growing season clusters in different tillage systems.</p

Long-term effects of rotation diversity and tillage on mean and cumulative corn and soybean yields.

<p>Long-term effects of rotation diversity and tillage on mean and cumulative corn and soybean yields.</p