Long-Term Crop Rotation Diversification Enhances Maize Drought Resistance Through Soil Organic Matter

Climate change adaptation requires building agricultural system resilience to warmer, drier climates. Increasing temporal plant diversity through crop rotation diversification increases yields of some crops under drought, but its potential to enhance crop drought resistance and the underlying mechanisms remain unclear. We conducted a drought manipulation experiment using rainout shelters embedded within a 36-year crop rotation diversity and no-till experiment in a temperate climate and measured a suite of soil and crop developmental and eco-physiological traits in the field and laboratory. We show that diversifying maize-soybean rotations with small grain cereals and cover crops mitigated maize water stress at the leaf and canopy scales and reduced yield losses to drought by 17.1 ± 6.1%, while no-till did not affect maize drought resistance. Path analysis showed a strong correlation between soil organic matter and lower maize water stress despite no significant differences in soil organic matter between rotations or tillage treatments. This positive relationship between soil organic matter and maize water status was not mediated by higher soil water retention or infiltration as often hypothesized, nor differential depth of root water uptake as measured with stable isotopes, suggesting that other mechanisms are at play. Crop rotation diversification is an underappreciated drought management tool to adapt crop production to climate change through managing for soil organic matter

Challenges for agroecology development for the building of sustainable agri-food systems

Environmental and social crises in agriculture have led to growing recognition that more ecologically sustainable and socially just food and agricultural systems are needed. This thematic number of the International Journal of Agriculture and Natural Resources gathers the papers submitted to the workshop “Challenges for agroecology development for the building of sustainable agri-food systems,” an OECD Co-operative Research Programme-sponsored conference. The aim of the workshop was to promote the transition from conventional agriculture towards agroecology as a science, practice and social movement through sharing the experiences of different OECD countries: Australia, Canada, Chile, Colombia, Hungary, Italy, Netherlands, Norway, Spain, Sweden and the United States. The main topics discussed at the workshop included i) agroecology development in OECD countries: local experiences and international collaboration; ii) agroecology as a social movement and related public policies; iii) agroecology education to promote sustainable agri-food systems; and iv) science, innovation and technologies in agroecological systems. While not a comprehensive assessment of the state of agroecology in OECD countries, this thematic number integrates diverse perspectives on some main research and policy advances and uncovers some existing gaps in agroecology practice as an approach for transitioning towards ecologically sustainable and socially just agricultural systems