ARS plant physiologists Dale Shaner and Lori Wiles made this discovery from ongoing experiments on two irrigated fields at Colorado State University (CSU) at Fort Collins, Colo. Shaner and Wiles work in the ARS Water Management Research Unit at Fort Collins.
In collaboration with CSU colleague Neil Hansen, Shaner and Wiles compared the behavior of the herbicide atrazine in conventionally tilled corn grown continuously year after year versus corn grown in three different crop rotations. They tested various levels of tillage and irrigation, including no irrigation.
The amount of irrigation used—including a total absence of irrigation—had no impact on the rate of degradation of atrazine by soil microbes in the top foot of soil. The only factors that made a difference were prior herbicide use and the choice of crop sequences, with prior herbicide use the most important factor by far.
Earlier studies, including one by Shaner, have shown that previous applications of atrazine can predispose soil to more quickly degrade later applications of the herbicide. But until now, it was not clear if other factors such as cropping history and quantity of irrigation played a role.
There are two consequences of the more rapid dissipation of atrazine in the plots with a history of use. The first consequence is a loss in weed control. In the plots with the most rapid dissipation, weeds began to re-infest the plots within four weeks after treatment, while the plots with the slowest rate of dissipation remained weed-free through the growing season.
The second consequence is that atrazine leached more deeply in the soil in the plots where it did not dissipate rapidly, but the herbicide did not move below the top three inches of the soil in the plots where it was degraded rapidly.
This research was published in the Journal of Environmental Quality.
ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture. The research supports the USDA priority of promoting international food security.
Don Comis | EurekAlert!
Researchers discover natural product that could lead to new class of commercial herbicide
16.07.2018 | UCLA Samueli School of Engineering
Advance warning system via cell phone app: Avoiding extreme weather damage in agriculture
12.07.2018 | Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Transportation and Logistics
16.07.2018 | Agricultural and Forestry Science