Study: adding small amount of dairy and meat to diet results in more efficient land use than full vegetarian diet
A low-fat vegetarian diet is very efficient in terms of how much land is needed to support it. But adding some dairy products and a limited amount of meat may actually increase this efficiency, researchers from Cornell University suggest.
The study, published in the journal Renewable Agriculture and Food Systems, is the first to examine the land requirements of complete diets. The researchers compared 42 diets with the same number of calories and a core of grains, fruits, vegetables and dairy products (using only foods that can be produced in New York state), but with varying amounts of meat (from none to 13.4 ounces daily) and fat (from 20 to 45 percent of calories) to determine each diet's 'agricultural land footprint'. They found a fivefold difference between the two extremes.
Thus, although vegetarian diets in New York state may require less land per person, they use more high-valued land. While meat increases land-use requirements, diets including modest amounts of meat can feed more people than some higher fat vegetarian diets:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: carrying capacity :: diet :: food :: land use ::
The key to conserving land and other resources with our diets is to limit the amount of meat we eat and for farmers to rely more on grazing and forages to feed their livestock, says Jennifer Wilkins, senior extension associate in nutritional sciences who specializes in the connection between local food systems and health and co-authored the study with Gary Fick, Cornell professor of crop and soil sciences. Consumers need to be aware that foods differ not only in their nutrient content but in the amount of resources required to produce, process, package and transport them, she adds.
According to the U.S. Department of Agriculture, the average American ate approximately 5.8 ounces of meat and eggs a day in 2005. In order to reach the efficiency in land use of moderate-fat, vegetarian diets, the new study suggests that New Yorkers would need to limit their annual meat and egg intake to about 2 cooked ounces a day.
References:
Christian J. Peters, Jennifer L. Wilkins and Gary W. Fick, "Testing a complete-diet model for estimating the land resource requirements of food consumption and agricultural carrying capacity: The New York State example", Renewable Agriculture and Food Systems (2007), 22: 145-153, doi:10.1017/S1742170507001767
Cornell Chronicles: Diet for small planet may be most efficient if it includes dairy and a little meat, Cornell researchers report - October 4, 2007.
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Even though a moderate-fat plant-based diet with a little meat and dairy (red footprint) uses more land than the all-vegetarian diet (far left footprint), it feeds more people (is more efficient) because it uses more pasture land, which is widely available.
This counter-intuitive deduction stems from the findings of their new study, which concludes that if everyone in New York state followed a low-fat vegetarian diet, the state could directly support almost 50 percent more people, or about 32 percent of its population, agriculturally. With today's high-meat, high-dairy diet, the state is able to support directly only 22 percent of its population, say the researchers.The study, published in the journal Renewable Agriculture and Food Systems, is the first to examine the land requirements of complete diets. The researchers compared 42 diets with the same number of calories and a core of grains, fruits, vegetables and dairy products (using only foods that can be produced in New York state), but with varying amounts of meat (from none to 13.4 ounces daily) and fat (from 20 to 45 percent of calories) to determine each diet's 'agricultural land footprint'. They found a fivefold difference between the two extremes.
A person following a low-fat vegetarian diet, for example, will need less than half (0.44) an acre per person per year to produce their food. A high-fat diet with a lot of meat, on the other hand, needs 2.11 acres. Surprisingly, however, a vegetarian diet is not necessarily the most efficient in terms of land use. - Christian Peters, lead author, postdoctoral associate in crop and soil sciencesThe reason for the lower land use efficiency of the all vegetarian diet is that fruits, vegetables and grains must be grown on high-quality cropland. Meat and dairy products from ruminant animals are supported by lower quality, but more widely available, land that can support pasture and hay. A large pool of such land is available in New York state because for sustainable use, most farmland requires a crop rotation with such perennial crops as pasture and hay.
Thus, although vegetarian diets in New York state may require less land per person, they use more high-valued land. While meat increases land-use requirements, diets including modest amounts of meat can feed more people than some higher fat vegetarian diets:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: carrying capacity :: diet :: food :: land use ::
The key to conserving land and other resources with our diets is to limit the amount of meat we eat and for farmers to rely more on grazing and forages to feed their livestock, says Jennifer Wilkins, senior extension associate in nutritional sciences who specializes in the connection between local food systems and health and co-authored the study with Gary Fick, Cornell professor of crop and soil sciences. Consumers need to be aware that foods differ not only in their nutrient content but in the amount of resources required to produce, process, package and transport them, she adds.
According to the U.S. Department of Agriculture, the average American ate approximately 5.8 ounces of meat and eggs a day in 2005. In order to reach the efficiency in land use of moderate-fat, vegetarian diets, the new study suggests that New Yorkers would need to limit their annual meat and egg intake to about 2 cooked ounces a day.
References:
Christian J. Peters, Jennifer L. Wilkins and Gary W. Fick, "Testing a complete-diet model for estimating the land resource requirements of food consumption and agricultural carrying capacity: The New York State example", Renewable Agriculture and Food Systems (2007), 22: 145-153, doi:10.1017/S1742170507001767
Cornell Chronicles: Diet for small planet may be most efficient if it includes dairy and a little meat, Cornell researchers report - October 4, 2007.
Article continues
Tuesday, October 09, 2007
Researchers find genetically engineered corn could affect aquatic ecosystems
Researchers, including Todd V. Royer, an assistant professor in the IU School of Public and Environmental Affairs, established that pollen and other plant parts containing toxins from genetically engineered Bt corn are washing into streams near cornfields.
They also conducted laboratory trials that found consumption of Bt corn byproducts produced increased mortality and reduced growth in caddisflies, aquatic insects that are related to the pests targeted by the toxin in Bt corn.
Caddisflies are a food resource for higher organisms like fish and amphibians. If the goal is to have healthy, functioning ecosystems, there is a need to protect all the parts. Water resources are something populations depend on greatly.
Bt corn is engineered to include a gene from the micro-organism Bacillus thuringiensis, which produces a toxin that protects the crop from pests, in particular the European corn borer. It was licensed for use in 1996 and quickly gained popularity. In 2006, around 35 percent of corn acreage planted in the U.S. was genetically modified, the study says, citing U.S. Department of Agriculture data.
Before licensing Bt corn, the U.S. Environmental Protection Agency conducted trials to test its impact on water biota. But it used Daphnia, a crustacean commonly used for toxicity tests, and not insects that are more closely related to the target pests:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: corn :: GMO ::
Royer emphasizes that, if there are unintended consequences of planting genetically engineered crops, farmers shouldn't be held responsible. In a competitive agricultural economy, producers have to use the best technologies they can get.
There was a public flap over the growing use of Bt corn in 1999, when a report indicated it might harm monarch butterflies. But studies coordinated by the government's Agriculture Research Service and published in PNAS concluded there was not a significant threat to monarchs. Around that time, Royer said, he and his colleagues wondered whether the toxin from Bt corn was getting into streams near cornfields; and, if so, whether it could have an impact on aquatic insects.
Their research, conducted in 2005 and 2006 in an intensely farmed region of northern Indiana, measured inputs of Bt corn pollen and corn byproducts (e.g., leaves and cobs) in 12 headwater streams, using litter traps to collect the materials. They also found corn pollen in the guts of certain caddisflies, showing they were feeding on corn pollen.
In laboratory trials, the researchers found caddisflies that were fed leaves from Bt corn had growth rates that were less than half those of caddisflies fed non-Bt corn litter. They also found that a different type of caddisfly had significantly increased mortality rates when exposed to Bt corn pollen at concentrations between two and three times the maximum found in the test sites.
Royer said there was considerable variation in the amount of corn pollen and byproducts found at study locations. And there is likely also to be significant geographical variation; farmers in Iowa and Illinois, for example, are planting more Bt corn than those in Indiana. The level of Bt corn pollen associated with increased mortality in caddisflies could potentially represent conditions in streams of the western Corn Belt.
Other principal investigators for the study were Emma Rosi-Marshall of Loyola University Chicago, Jennifer Tank of the University of Notre Dame and Matt Whiles of Southern Illinois University. It was funded by the National Science Foundation.
References:
E. J. Rosi-Marshall, J. L. Tank, T. V. Royer, M. R. Whiles, M. Evans-White, C. Chambers, N. A. Griffiths, J. Pokelsek, and M. L. Stephen, "Toxins in transgenic crop byproducts may affect headwater stream ecosystems", Proc. Natl. Acad. Sci., 10.1073/pnas.0707177104, Published online before print October 8, 2007
Eurekalert: Study shows genetically engineered corn could affect aquatic ecosystems - October 8, 2007.
Biopact: GM field trials 'underestimate potential for cross-pollination' - study - June 01, 2007
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posted by Biopact team at 5:21 PM 3 comments links to this post