One of the key questions facing agriculturalists in the 21st century is how to produce adequate amounts of food and farm income while protecting environmental quality. Diversified, low-external-input (LEI) farming systems offer one possible approach for maintaining adequate productivity and profitability while reducing pollution by agrichemicals and still improving water quality. LEI systems rely heavily on ecological processes for soil fertility and pest management, but can include some use of synthetic fertilizers and pesticides.
A team of investigators based at Iowa State University conducted a multiyear field experiment in Boone County, IA, to determine whether the yield, weed suppression, and profit characteristics of LEI systems can match or exceed those of a conventional system. Results from the study were published in the May-June 2008 issue of Agronomy Journal.
The experiment included a two-year, corn-soybean rotation, a three-year corn-soybean-small grain-red clover rotation, and a four-year corn-soybean-small grain-alfalfa-alfalfa rotation. Conventional rates of synthetic fertilizers were applied in the two-year rotation, whereas composted cattle manure and reduced rates of synthetic fertilizers were applied in the three- and four-year rotations. Weed management in the two-year rotation was based on conventional rates of herbicides, whereas in the three- and four-year systems, herbicides were applied in bands in corn and soybean, greater reliance was placed on cultivation, and no herbicides were applied in small grain and forage legume crops.
Over the period of 2003-2006, both synthetic Nitrogen fertilizer and herbicide use was lower in the three- and four-year LEI systems than in the two-year conventional system. Corn and soybean yields were as high or higher in the LEI systems as in the conventional system, and matched or exceeded average yields on commercial farms in Boone County. Further, lower herbicide inputs did not lead to increased weed problems. Without government subsidy payments, net returns were highest for the four-year LEI system, lowest for the three-year LEI system, and intermediate for the two-year conventional system. With subsidies, differences among systems in net returns were smaller, as subsidies favored the conventional system, but rank order of the systems was maintained.
“The results suggest that large reductions in agrichemical use can be compatible with high crop yields and profits,” says Dr. Matt Liebman, an agronomy professor at Iowa State University.
The project was supported by the USDA National Research Initiative (Biology of Weedy and Invasive Species Panel), and the Leopold Center for Sustainable Agriculture and the Department of Agronomy at Iowa State University. The project is continuing with additional investigations of energy use, soil quality, and weed population dynamics. Additional economic analyses will be conducted to determine the impacts of rapidly changing crop prices and input costs.
Sara Uttech | EurekAlert!
Back to Nature: Palm oil plantations are being turned back into protected rainforest
21.03.2019 | Forschungsverbund Berlin e.V.
The inner struggle of the evening primrose: Chloroplasts are caught up in an evolutionary arms race
14.03.2019 | Max-Planck-Institut für Molekulare Pflanzenphysiologie
DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.
The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...
Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.
The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...
Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.
Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.
A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...
Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.
"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...
11.03.2019 | Event News
01.03.2019 | Event News
28.02.2019 | Event News
22.03.2019 | Life Sciences
22.03.2019 | Life Sciences
22.03.2019 | Information Technology