Prairie soil organic matter shown to be resilient under intensive agricultureJanuary 16, 2009A recent study has confirmed that although there was a large reduction of organic carbon and total nitrogen pools when prairies were first cultivated and drained, there has been no consistent pattern in these organic matter pools during the period of synthetic fertilizer use, that is, from 1957-2002. "For these prairie soils, some of the best in the world, declines in organic matter from cultivation were likely completed by the 1950s, and since then organic matter pools have remained relatively constant under modern production practices," said U of I biogeochemist Mark David who led the study. Carbon and nitrogen pools in soil, which are part of organic matter, are important because their alteration can affect greenhouse gases, the sustainability of agricultural production, and are a measure of soil quality. "Monitoring the change through time is important, but can present difficulties because short term, soil-landscape variability accounts for considerable differences in soil organic matter, and it is slow to respond to management shifts," David said. "Most of the decline in organic matter occurred in the top 50 centimeters of soil, with evidence that carbon and nitrogen moved from the upper soil layers to deeper ones, possibly enhanced by tile drainage," David said. The study utilized previously sampled fields, archived soil samples, and made use of prairie remnants to document changes in soil carbon and nitrogen pools in response to agricultural production. Another member of the research team, soil scientist Robert Darmody said that much of the early documentation was from samples collected in central Illinois from 1901 to 1904 by Cyril Hopkins, who was head of the Department of Agronomy at the time. "His meticulous field notes and maps, laboratory analysis books, and archived samples allowed us to resample fields to compare current soil carbon and nitrogen pools in these fields to those from 100 years earlier." "Actual archived soil samples, in glass jars, allowed modern chemical techniques to be compared to early ones," Darmody said. Soil Conservation Service sampling sites and data from 1957 were also utilized, so that soil changes during the modern production era of fertilizers, pesticides, and hybrids could be evaluated. In addition, current prairie remnants were sampled and matched with nearby agricultural fields. "Analytical values of carbon and nitrogen on the archived soil samples were found to match extremely well with modern analytical techniques," said environmental scientist Greg McIsaac. "Without the stored samples, it would have been difficult to know if the data could be compared to modern analyses." McIsaac noted that the University of Illinois has a unique and large archive of soil samples, numbering in the thousands, from this early period and throughout the 20th century, including samples from the Morrow Plots. David said that over long-time periods, locations of sampling sites are lost, and few samples are archived. "Although the conversion of prairie soils to agricultural fields in the Midwest has been documented to reduce organic matter, there is relatively little information across decades on the changes and profile distribution of organic carbon and nitrogen in artificially drained agricultural soils." University of Illinois at Urbana-Champaign |
|||||||||||||||||||||
| Related Organic Matter Current Events and Organic Matter News Articles ORNL, Los Alamos pioneer new approach to assist scientists, farmers Sustainable farming, initially adopted to preserve soil quality for future generations, may also play a role in maintaining a healthy climate, according to researchers at the Department of Energy's Oak Ridge and Los Alamos national laboratories. Oceans' uptake of manmade carbon may be slowing The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. DNA barcodes: Creative new uses span health, fraud, smuggling, history, more The scientific ability to quickly and accurately identify species through DNA "barcoding" is being embraced and applied by a growing legion of global authorities - from medical and agricultural researchers to police and customs authorities to palaeontologists and others. Organic weed control options for highbush blueberry Research scientists at Nova Scotia Agricultural College have been working steadily to find effective organic methods to control weeds in cultivated blueberry crops. Climate variability impacts the deep sea Deep-sea ecosystems occupying 60% of the Earth's surface could be vulnerable to the effects of global warming warn scientists writing in the Proceedings of the National Academy of Sciences. Designer molecule detects tiny amounts of cyanide, then glows A small molecule designed to detect cyanide in water samples works quickly, is easy to use, and glows under ultraviolet or "black" light. Arctic land and seas account for up to 25 percent of world's carbon sink In a new study in the journal Ecological Monographs, ecologists estimate that Arctic lands and oceans are responsible for up to 25 percent of the global net sink of atmospheric carbon dioxide. Key new ingredient in climate model refines global predictions For the first time, climate scientists from across the country have successfully incorporated the nitrogen cycle into global simulations for climate change, questioning previous assumptions regarding carbon feedback and potentially helping to refine model forecasts about global warming. Mystery Solved: Marine Microbe Is Source of Rare Nutrient A new study of microscopic marine microbes, called phytoplankton, by researchers at Woods Hole Oceanographic Institution (WHOI) and the University of South Carolina has solved a ten-year-old mystery about the source of an essential nutrient in the ocean. Help Students Think like Soil Scientists Emphasizing cross-disciplinary concepts in teaching soil science courses, such as mass-volume relationships, can help undergraduates learn real-world, problem-solving skills that are crucial to their success in soil science careers. More Organic Matter Current Events and Organic Matter News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||