Increasing Crop Diversity Improves Yield Stability.

Monocultures and short crop rotations are often thought to be more productive and economically rewarding than diversified cropping systems. However, crop diversification has long been recommended as a key strategy for building resilience. In an agricultural context, resilience is defined as the cropping system’s ability to experience biotic and abiotic stresses and retain yields. We hypothesized that sound rotation, with a broader range of crops including legumes, help maintain soil and ecosystem’s capacity to function and buffer against weather variations on the long term. We present here results from a 30-year rotation trial including 8 popular temperate crop rotations grown under two tillage practices in Ontario, Canada. We show that maize, soybean and wheat yields present less variation when grown in longer rotations, especially when dry spells occur during silking and grain filling. We also describe the importance of tillage practices in building resilience. Our results suggest that diversification of agricultural crops is a rational strategy for developing hardy agricultural systems and protecting food production against the upcoming extreme weather events. As a large amount of resources are currently being invested into crop improvement for tolerance to stresses, complementary management practices such as crop diversification and no till could enhance chances of success of such varieties and sustainably decrease yield gaps when environmental stresses occur.