(Credit: USDA NRCS Montana/Flickr)
Rotating corn and soybeans could potentially contribute to long-term declines in soil organic matter, researchers report.
A new study, published in Plant and Soil, examines the mechanisms that drive the decomposition of organic matter in soils that undergo long-term corn and soybean rotations.
Corn and soybean rotations can provide important environmental and management benefits for farmers, but the practice also comes with tradeoffs, says Steven Hall, an assistant professor of ecology, evolution, and organismal biology at Iowa State University.
“It could be that the benefits of corn and soybean rotation may also come with some long-term costs,” he says.
Rotating corn and soybeans allows farmers to use less nitrogen fertilizer when growing corn. That benefits the environment and allows farmers to save on input costs.
However, studies have noted corn-soybean crop rotation leads to lower organic matter in the soil when compared to land that undergoes continuous corn production, or when farmers include other crops in rotation along with corn and soybeans.
Optimal levels of soil organic matter, usually composed of dead plants and microbial residues, help crops thrive by releasing nutrients into the soil and allowing soils to retain moisture, researchers say.
Researchers previously suspected that organic matter decline could be due to the fact that soybeans simply deposit less organic matter than corn does, meaning land that undergoes corn-soybean rotation will end up with less organic matter than land where corn is grown continuously, Hall says. The new study also points to unique synergies that arise from rotating the two crops.
Soybeans leave nitrogen-rich residue in the soil, which leads to vigorous growth of decomposer bacteria and fungi microbes. Corn plants, when they’re rotated onto those same acres, have relatively nitrogen-poor residue, so the soil microbes turn to attack older organic matter in the soil as a source of nitrogen to keep up with the consumption levels they were used to under soybeans.
This process likely contributes to the soybean nitrogen credit, but played out over the course of years, it may stimulate the decomposition of organic matter in the soil.
“The microbes get fat and happy with soybeans and then need to go elsewhere for nutrients when they decompose corn,” Hall says. “With continuous corn, those microbes are apparently less vigorous.”
It may be possible to sustain or increase organic matter by introducing other grains and legumes as well as cover crops, such as rye or oats, into corn and soybean crop rotations, Hall says. That way, farmers could retain the benefits of rotating their crops while replacing organic matter.
Researchers conducted study in the lab over the course of a year. Scaling the research up to the field level is the next step, but Hall says that could prove difficult because controlling all of the relevant variables in a field setting would pose challenges.
Source: Iowa State University
Climate Adaptation Finance and Investment in California
by Jesse M. Keenan
This book serves as a guide for local governments and private enterprises as they navigate the unchartered waters of investing in climate change adaptation and resilience. This book serves not only as a resource guide for identifying potential funding sources but also as a roadmap for asset management and public finance processes. It highlights practical synergies between funding mechanisms, as well as the conflicts that may arise between varying interests and strategies. While the main focus of this work is on the State of California, this book offers broader insights for how states, local governments and private enterprises can take those critical first steps in investing in society’s collective adaptation to climate change. Available On Amazon
Nature-Based Solutions to Climate Change Adaptation in Urban Areas: Linkages between Science, Policy and Practice
by Nadja Kabisch, Horst Korn, Jutta Stadler, Aletta Bonn
This open access book brings together research findings and experiences from science, policy and practice to highlight and debate the importance of nature-based solutions to climate change adaptation in urban areas. Emphasis is given to the potential of nature-based approaches to create multiple-benefits for society.
The expert contributions present recommendations for creating synergies between ongoing policy processes, scientific programmes and practical implementation of climate change and nature conservation measures in global urban areas. Available On Amazon
A Critical Approach to Climate Change Adaptation: Discourses, Policies and Practices
by Silja Klepp, Libertad Chavez-Rodriguez
This edited volume brings together critical research on climate change adaptation discourses, policies, and practices from a multi-disciplinary perspective. Drawing on examples from countries including Colombia, Mexico, Canada, Germany, Russia, Tanzania, Indonesia, and the Pacific Islands, the chapters describe how adaptation measures are interpreted, transformed, and implemented at grassroots level and how these measures are changing or interfering with power relations, legal pluralismm and local (ecological) knowledge. As a whole, the book challenges established perspectives of climate change adaptation by taking into account issues of cultural diversity, environmental justicem and human rights, as well as feminist or intersectional approaches. This innovative approach allows for analyses of the new configurations of knowledge and power that are evolving in the name of climate change adaptation. Available On Amazon
From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.