Cropping Systems: White Bean Diversity And Nitrogen Efficiency

The overall objective of the project is to reduce nitrogen fertilizer use in dry bean production by 50% over 7 years. This would be a major advance in profitability for the dry bean industry in Canada and would significantly improve the ecological footprint of the crop.

What challenge does “Cropping Systems – White Bean Diversity and Nitrogen Efficiency” address?

Between 1960 and 2000, the green revolution doubled world grain production, averting predicted mass starvation and world order changes during a period of rapid global population growth. This revolution was based on the use of improved plant varieties coupled with effective inputs and improved management practices. Today, similar concerns exist about feeding a projected population of 9 billion people by 2050. There is also increasing public interest in achieving crop production targets, reducing the use of inputs such as fertilizers and agrochemicals, and adoption of practices to increase diversity at all levels: the soil microbiome, plant varieties and cropping systems.

Although dry bean are legumes, their nitrogen (N2)-fixing ability is often characterized as poor, compared to other legumes. Therefore, application of nitrogen fertilizers in bean fields is a common practice to achieve high yields. However, plants cannot utilize all the nitrogen fertilizer that is applied to the soil, leading to runoff and groundwater contamination.

Nitrogen management study at Elora Research Station.

How will this research address the challenge?

Cultivar mixture cropping has benefits over monoculture cropping in controlling disease, increasing water use efficiency and increasing yield stability. Recent work by this research team has identified bean varieties and breeding lines with greater potential for N2 fixation which show potential as the starting point for a breeding effort to produce high N2-fixing dry beans.

This project explores the feasibility of increasing genetic diversity in cropping systems by using mixtures of common bean varieties instead of monocultures, and examines the potential of developing high yielding bean varieties that obtain a significant fraction of their nitrogen requirements through associations with Rhizobium nitrogen fixers rather than nitrogen fertilizer.

What impact will the project have on agriculture?

The research has the potential to provide a theoretical basis for the use of precision agriculture tools to plant fields with mixtures instead of monocultures. It could lead to greater in-field diversity in the crop and in the above and below ground ecosystems that might provide greater buffering capacity and resiliency for the cropping system.

A research trial using bean variety mixtures to increase crop diversity and ecosystem services at Elora Research Station.

Key messages

General adoption of the use of variety mixtures, instead of pure lines, would revolutionize on-farm cropping system practices and supporting research. For the latter, it would require a whole new level of testing for interactions in variety trials and agrochemical trials and require different approaches to breeding crops.

The overall objective of the project is to reduce nitrogen fertilizer use in dry bean production by 50% over 7 years. This would be a major advance in profitability for the dry bean industry in Canada and would significantly improve the ecological footprint of the crop.

Other information

Partners: Ontario Bean Growers, Agriculture Agri-Food Canada, Hensall District Coop.

Collaborators and students: Yarmilla Reiprecht (Research Associate), Yunfei Jiang (Post doc), Jennifer Wilker (PhD student).