Key Findings
Research from an international group of scientists—among them NH Agricultural Experiment Station scientist Stuart Grandy—shows that complex crop rotations can benefit levels of nitrogen even during droughts, when the application of nitrogen fertilizers can be less effective.
About the Co-Author
A. Stuart Grandy, Professor of Natural Resources and the Environment
Contact information: Stuart.Grandy@unh.edu
603-862-1075, Soil Biogeochemistry & Fertility Lab website
This research first published in Soil Biology and Biochemistry.
Researchers: T. Bowles, A. Jilling, K. Moran-Rivera, J. Schnecker and A. S. Grandy.
When it comes to crop rotations, complexity is key to boosting levels of nitrogen—a soil nutrient that is critical to crop production. However, new research from an international group of scientists—among them UNH researcher Stuart Grandy, complex crop rotations can benefit levels of nitrogen even during droughts too.
Grandy, along with researchers from the University of California Berkeley, Oklahoma State University, the University of Hawaii, and the University of Vienna, published their research in Soil Biology and Biochemistry. Their study had both fundamental and applied components, said Grandy. On the fundamental side, they were looking at the areas that soils accumulated – or “pooled” – nitrogen within for use by plants, and which of those areas (for example, in the soil microbes, in decomposing organic matter, or in organic nitrogen pools associated with the mineral particles themselves) did plants tap into for nutrient uptake. Nutrient uptake refers to the ability of plants to pull in nutrients from the soil. On the applied side, they wanted to know which crop rotation patterns most impacted nitrogen pools and how did drought and non-drought conditions affect the ability of plants to access that nitrogen from different soil pools.
“We found that the MAOM does supply nutrients to plants. And we believe that under limited water, that that’s a specific nitrogen pool that plants tap into,” Grandy said. “Additionally, we learned that complex crop rotations are building up nitrogen specifically within that MAOM, making these complex rotations more resilient to water variability.”
“So ultimately, what we learned from this study is that the greater the crop diversity, the greater the potential to increase soil nitrogen, and the greater the ability of those plants surviving – or even thriving – during drought conditions.”
Ultimately, what we learned from this study is that the greater the crop diversity, the greater the potential to increase soil nitrogen, and the greater the ability of those plants surviving – or even thriving – during drought conditions.
This material is based on work supported by the NH Agricultural Experiment Station through joint funding from the USDA National Institute of Food and Agriculture (under Hatch award number 1020144) and the state of New Hampshire. Support for this research was also provided by the National Science Foundation's Long-term Ecological Research Program (DEB 1832042) at the Kellogg Biological Station and by Michigan State University AgBioResearch. Co-authors include T. Bowles, A. Jilling, K. Moran-Rivera, J. Schnecker and A. S. Grandy.
