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!
Alkaline soil, sensible sensor
03.08.2017 | American Society of Agronomy
New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences