The practice of no-till has increased considerably during the past 20 yr. The absence of tillage coupled with the accumulation of crop residues at the soil surface modifies several soil properties but also influence nitrogen dynamics.
Soils under no-till usually host a more abundant and diverse biota and are less prone to erosion, water loss, and structural breakdown than tilled soils. Their organic matter content is also often increased. In addition, no-till is proposed as a measure to mitigate the increase in atmospheric carbon dioxide concentration. To assess the net effect of no-till on greenhouse gas emissions, other gases also have to be examined.
Researchers at Agriculture and Agri-Food Canada (Québec City) investigated the short-term impacts of no-till on soil nitrous oxide emissions. They compared emissions of nitrous oxide as well as nitrogen contents and physical properties between moldboard plowed (early fall) and no-till soils near Québec City, Canada. Measurements were made during three growing seasons in a poorly drained clay and a well-drained loamy soil cropped to barley. The results of the study were reported in the 2008 September-October issue of the Soil Science Society of America Journal.
The authors concluded that their investigation indicates “that no-till can result in incremental nitrous oxide emissions that can more than offset the soil carbon dioxide sink during the first 5 yr after adoption of this soil conservation practice in a heavy clay soil…. Consequently, the potential of no-till for decreasing net greenhouse gas emissions may be limited in fine-textured soils that are prone to high water content and reduced aeration”.
Differences in the response of nitrous oxide emissions when converting to a no-till practice between the clay and loam soils were striking. While emissions were similar in both tillage treatments in the well-aerated loam, they more than doubled under no-till in the clay soil. Differences in emissions between tillage practices in the clay soil were observed in spring and summer but were greater and more consistent in the fall after plowing operations. The influence of plowing on nitrous oxide flux in the heavy clay soil was likely the result of increased soil porosity that maintained soil aeration and water content at levels restricting denitrification and nitrous oxide production. Accordingly, denitrification rates are usually increased in denser and wetter no-till soils and the anticipated benefits of the adoption of soil conservation practices on net soil-surface greenhouse gas emissions could be offset by increases in nitrous oxide emissions.
Predicting the impacts of no-till on nitrous oxide emissions is required for a full assessment of the influence of this practice on net greenhouse gas emissions. Researchers at Agriculture and Agri-Food Canada are pursuing their investigations to understand the factors that control the mechanisms leading to nitrous oxide emissions under contrasting soil tillage practices. Specifically, they now focus their efforts on the role of soil aeration with the hypothesis that the “adoption of no-till only increases nitrous oxide emissions in poorly aerated soils”. Field studies and mathematical modeling of the impact of no-till on soil nitrous oxide emission has yielded contrasting results and an explanation of the high intersite variability of the influence of no-till on soil nitrous oxide emissions is still lacking.
The full article is available for no charge for 30 days following the date of this summary. View the abstract at http://soil.scijournals.org/cgi/content/abstract/72/5/1363.
Soil Science Society of America Journal, http://soil.scijournals.org, is a peer-reviewed international journal published six times a year by the Soil Science Society of America. Its contents focus on research relating to physics; chemistry; biology and biochemistry; fertility and plant nutrition; genesis, morphology, and classification; water management and conservation; forest, range, and wildland soils; nutrient management and soil and plant analysis; mineralogy; and wetland soils.
The Soil Science Society of America (SSSA) is a progressive, international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, and founded in 1936, SSSA is the professional home for 6,000+ members dedicated to advancing the field of soil science. It provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use.
SSSA supports its members by providing quality research-based publications, educational programs, certifications, and science policy initiatives via a Washington, DC, office. For more information, visit www.soils.org.
SSSA is the founding sponsor of an approximately 5,000-square foot exhibition, Dig It! The Secrets of Soil, which opened on July 19, 2008 at the Smithsonian's Natural History Museum in Washington, DC.
Sara Uttech | EurekAlert!
Cascading use is also beneficial for wood
11.12.2017 | Technische Universität München
The future of crop engineering
08.12.2017 | Max-Planck-Institut für Biochemie
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
13.12.2017 | Health and Medicine
13.12.2017 | Physics and Astronomy
13.12.2017 | Life Sciences