Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Reducing fossil energy use on the farm

03.05.2010
The impacts of low-external-input cropping systems on energy and yield

Conventional agriculture production relies heavily on fossil fuels, particularly in its ability to provide energy at a low cost. However, the uncertain future of fossil fuel availability and prices point to need to explore energy efficiencies in other cropping systems.

Most of the U.S. Corn Belt relies on a two-year rotation of corn and soybean with heavy inputs of fertilizer, herbicides and pesticides derived from fossil fuels to achieve high yields keep costs low. Matt Liebman, Michael Cruse, and their colleagues at Iowa State University conducted a six-year study to compare energy use of a conventionally managed corn and soybean system with two low input cropping systems that use more diverse crops and manure applications, but also use less fertilizer and herbicides. The results were published in the May/June 2010 edition of Agronomy Journal, published by the American Society of Agronomy.

The two input systems consisted of a three-year rotation of corn-soybean/small grain/red clover and a four-year rotation of corn-soybean-small grain/alfalfa-alfalfa. Between 2003 and 2008, nitrogen fertilizer inputs in the 3-year rotation decreased 66% and decreased 78% in the 4-year rotation. Herbicide use decreased 80% in the three-year rotation and 85% in the four-year rotation. Despite the energy input reduction, corn and soybean yields matched or exceeded the conventional system yields.

Did the application of manure decrease the fossil fuel energy costs? Manure prices are dependent on local economic conditions, but the two low-input systems used 23% to 56% less fossil energy than conventional systems. To analyze the energy and economic costs of manure application, the researchers used two approaches. One where manure was a waste product of live stock and essentially free of cost except for the energy used in its application, and a second approach as if the costs of manure were the same as commercial fertilizers. As a low economic input, manure can return $249 per acre, or $28 to $38 under high economic input for four and three-year systems, respectively.

Most of the fossil energy input for all systems was from grain drying and handling. Conditions in northern latitudes, where farmers have limited time to allow grain to dry in the field, make it difficult to reduce this cost. The researchers point out, however, that growing corn less frequently in a rotation sequence can reduce the need for grain drying with fossil energy.

The three and four-year rotation plans rely on agriculture systems where livestock feeding, manure application are integrated into crop production practices. "Iowa has a long history of mixed crop and livestock farming, although these operations do require more management and labor," said Liebman. "If fossil energy costs rise steeply, we may see more of them again."

While fossil energy inputs may decrease with manure application and increased crop rotation, the opposite trend is true for labor inputs. A two-year rotation required 41 minutes per acre per year, with a three-year rotation increasing labor 54%, and a four-year rotation requiring 91% more labor. However, the increases in labor were mainly in parts of the year not associated with corn or soybean production activities.

The researchers conclude that low energy prices and high wages contributed to the adoption of the conventional two-year corn/soybean rotation. Fossil fuels offset labor costs and allow net economic returns to remain constant. If demand from ethanol or overseas grain markets increase, or if biofuels from corn stover become economically viable, Midwest cropping systems may continue on a trend of less diversity and more corn. However, if fossil energy prices rise without an increase in crop value, diversified cropping systems may become more preferable.

"It's hard to predict the exact details of what the future will bring us," said Liebman. "But results of this study show that we do have options for maintaining high farm productivity and profitability while substantially reducing our dependence on fossil energy."

The research team was funded by the Leopold Center for Sustainable Agriculture and the U.S. Department of Agriculture. It is expanding its activities into measurements of effects of the different cropping systems on water quality, greenhouse gas emissions, and soil carbon and nitrogen dynamics.

The full article is available for no charge for 30 days following the date of this summary. View the abstract at https://www.agronomy.org/files/publications/agronomy-journal/abstracts/102-3/aj09-0457-abstract.pdf.

A peer-reviewed international journal of agriculture and natural resource sciences, Agronomy Journal is published six times a year by the American Society of Agronomy, with articles relating to original research in soil science, crop science, agroclimatology and agronomic modeling, production agriculture, and software. For more information visit: http://agron.scijournals.org.

The American Society of Agronomy (ASA) www.agronomy.org, is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.

Sara Uttech | EurekAlert!
Further information:
http://www.sciencesocieties.org
http://www.agronomy.org

More articles from Agricultural and Forestry Science:

nachricht Trees and climate change: Faster growth, lighter wood
14.08.2018 | Technische Universität München

nachricht Animals and fungi enhance the performance of forests
01.08.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Biosensor allows real-time oxygen monitoring for 'organs-on-a-chip'

21.08.2018 | Medical Engineering

Researchers discover link between magnetic field strength and temperature

21.08.2018 | Physics and Astronomy

IHP technology ready for space flights

21.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>