Evaluating the potential for double cropping in canada: Effect of seeding date and relative maturity on the development and yield of maize, white bean, and soybean

The study of the sustainable intensification of agriculture aims to balance the need to increase production with the goal of reducing the environmental impacts of agricultural practices. One possibility for intensification is the practice of double cropping - sequentially harvesting two crops in one year from the same parcel of land. Double cropping is not a new practice, it occurs on approximately 2% of crop land in the United States annually. In Canada, however, double cropping is not presently a common practice, even though the long-term climate averages suggest that the practice should be possible in the most southern portions of the country. An experiment was conducted to explore the possibility for double cropping in southern Ontario using three crops, maize, soybean and white bean, seeded at five seeding dates spanning late June through early August. Results of this research demonstrate that double cropping following winter wheat is a viable cropping practice in the most southern portions of Canada. While yields of all three crops did decline as the seeding date was delayed into late summer, these reductions can be minimized by selecting hybrids or varieties with shorter relative maturities than are typically grown in southern Ontario. This will ensure that the double crop has sufficient growing degree days to reach maturity and reduce the impact of declining daylength on crop development. Even though season length still represents the most significant limitation to double cropping in Canada, our results clearly demonstrate that with the appropriate selection of crop hybrids and varieties, there is a seeding date window where maize, soybean or white bean perform well as a summer seeded double crop in southern Ontario.