Organic Farms Can Pollute Too

Scientists found higher levels of nitrogen pollution beneath organic farms than farms using synthetic fertilizers. Continue reading →

Organic agriculture can pollute groundwater more than conventional synthetic chemical fertilization systems, researchers have found.

Israeli scientists measured the amount of nitrate, a form of nitrogen that plants consume, in the deep soil beneath crops grown using composted manure mixed into the soil. The team of biologists, agronomists and geologists also measured the levels of nitrate beneath crops fertilized with liquid synthetic fertilizer mixed into drip irrigation water, a system known as fertigation. Much higher levels of nitrate existed beneath the organic crops.

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Soil directly beneath organically farmed green houses contained a maximum of 724 milligrams of nitrate per liter (mg/L) of soil at a depth of 2.5 meters. At that depth, the roots of the plants were unable to grab the nutrients, so the nitrate was destined to eventually sink into the groundwater. Nitrate contamination beneath organic crops averaged 357 mg/L. The results have been published in the journal Hydrology and Earth System Sciences.

Nitrate levels under crops receiving synthetic fertilizer averaged 38 mg/L. However, these fertigated crops had higher levels of nitrate in the upper soil where the plants roots could actually feed on the nutrients. Nitrate levels averaged 270 mg/L in the root zone of fertigated crops, compared to 109 mg/L in the organic crops' root zones.

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The researchers suggested that the increased contamination beneath organic crops may result from compost being applied to the soil before the plants are sown. The compost provides nitrate to fertilize the crops. However, after the seeds sprout, the tiny plants can't absorb much nitrogen. Irrigation water leaches the unused nitrate into the deeper soil before the baby crops can devour the fertilizer. The synthetic fertilizers, on the other hand, are added incrementally to the irrigation water in amounts that the plants can absorb at different life stages.

The results of this study don't mean that organic agriculture necessarily pollutes more than conventional systems, however. Run off from synthetic nitrogen fertilization of lawns and crops leads to massive pollution of waterways and marine dead zones, such as the oxygen starved waters at the mouth of the Mississippi River in the Gulf of Mexico. The nitrogen fuels blooms of algae that suck oxygen from the water when they die and decompose. Fish and other marine life suffocate in these waters.

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The Israeli study does add to the evidence that organic agriculture doesn't provide a flawless solution to agricultural pollution. Besides pollution, the demand for organic produce led to farming of the parched Baja Peninsula of Mexico, reported the New York Times. The irrigation for the organic crops sucked water from scarce sources in the arid region and shattered the fragile ecology of the desert.

In rainier areas more suited to farming, organic agriculture can improve soil quality and foster a healthy community of microbes in the soil.

A worker sorts produce grown at an organic farm just south of the Dead Sea.

For years, opponents have argued that genetically engineered plants wreak havoc with human health and nature, and accuse plant biotech companies, such as Monsanto, of putting profits before people. On the other hand, agricultural biotech proponents argue that engineered crops enable farmers to grow at a time of global food shortages, insidious pests, weeds and extreme weather. "It's a complicated issue," says James E. McWilliams, author of American Pests and professor of history at Texas State University. Plant virologist Roger N. Beachy, president of the Donald Danforth Plant Center in St. Louis, Missouri, thinks that environmentalists and biotech experts can emerge from the cloud of controversy, find common ground, and move toward green goals together. So, whether transgenic crops make you think "yum-yum" or "no ma'am," McWilliams and Beachy share what's cooking:

1. Biofortified Soya Beans

What advantage did these few plants gain by evolving the ability to catch animals instead of just capturing the sun's energy? The elaborate structures necessary for killing bugs -- pools of nectar, bright colors, unusual shapes and digestive enzymes -- must be costly for the plant to make. Not so, says a new study, published in the American Journal of Botany, that examined Asian pitcher plants (pictured here), Venus flytraps, sundews and others.

2. Edible Cotton Seeds

By nature, cotton seeds are inedible because they contain gossypol, a component that keeps bugs away. In 2006, Texas A&M University and Cotton Inc. collaborated on research to produce genetically engineered seeds without the inedible part while keeping it in the plant for protection. The researchers made nutty-tasting meal from the seeds that could be used for flour, but the discovery has many regulatory and logistic hurdles to clear before it could be a reality in cotton-growing areas.

3. Jatropha

Food or energy? With gas prices soaring, biofuel advocates find themselves going toe-to-toe with farmers. Jatropha is an inedible plant whose seeds produce a liquid like palm oil that could be used for biofuel. Earlier this year the plant caused political tension in India, where tribal communities accused the government of destroying their native crops to plant jatropha for fuel needs. Plant breeding and genetic engineering will result in high-yielding jatropha that will increase overall production and potentially reduce the hectares needed; Roger Beachy says jatropha and other oil-producing, non-food plants also have the potential to produce bioplastics that can degrade in landfills.

4. Golden Rice

More than 120 million children globally don't get enough vitamin A and as a result are at risk for blindness. Back in the 1990s, a scientific team at the Swiss Federal Institute of Technology by Ingo Potrykis and collaborators at Syngenta Company discovered that adding several key genes from flowering plants to rice could dramatically increase the amount of beta carotene, a molecular that human beings can convert to Vitamin A. Even though the research ran into intellectual property rights problems, a public-private partnership between the inventors and agrichemical company Syngenta allowed the research to continue. Golden rice was successfully field-tested in Louisiana four years ago, but the inventors blame bureaucratic measures for slowing its adoption abroad.

5. Flood-Resistant Rice

Husband and wife team Pamela Ronald and Raoul Adamchak bridge the biotech-environmental divide in their book Tomorrow's Table, arguing that genetic-engineering and organic farming can be blended. Ronald, a professor of plant pathology at University of California-Davis, has been working with David Mackill of the International Rice Research Institute in the Philippines on genetically-modified rice that can withstand flooding. If field trials are successful, the rice could be available as early as next year.

6. Sugar Beets

For something that's so sweet, the debate over this crop has been rather bitter. Last year the New York Times chronicled sugar beet farmers' woes as they battled weeds to harvest the beets that provide around half the nation's sugar. They eagerly awaited Monsanto's Roundup Ready beets to produce higher yields and pay less for herbicide and workers to weed the fields. Environmentalists, meanwhile, raised alarm over the problem of weeds that are resistant to Roundup herbicide, cross-pollination with organic crops, and a group of advocates sued the U.S. Department of Agriculture over the matter. The beets became available to farmers earlier this year.

7. Yeast

Admittedly, this isn't a crop, but it will likely be cultivated like one. The London Times recently reported that a biotechnology company in San Francisco called LS9 had genetically modified industrial yeast to munch on plant sugars and excrete crude oil. No, really. The company plans to feed the yeast agricultural waste, although they haven't quite scaled up the operation up beyond the beaker level. And there's no word yet on whether they will be able to engineer some bugs to eat up all the carbon dioxide from combustion.

8. Cassava

This starchy, potato-like root is an essential plant for millions of people around the world, especially in Africa. This staple lacks a range of vitamins that are crucial to development and its cultivation can be adversely affected by drought. BioCassava Plus is a group of scientists led by Ohio State University Professor Richard Sayre and financed with a grant from the Bill and Melinda Gates Foundation. Currently they're working on a virus-resistant cassava that contains a day's worth of vitamins, proteins, and minerals. They plan to field test it in two African countries within the next two years.

9. Papaya

Plant pathologist Dennis Gonsalves has been involved in papaya research for 30 years. It's not a stretch to say that papayas might have been wiped out entirely had it not been for his work. A virus was rapidly eating up the orange-yellow tropical fruit when Gonsalves, then at Cornell University, and fellow researchers engineered the SunUp papaya strain. Earlier this year, the University of Hawaii-Menoa led a group of 85 scientists to decode the SunUp papaya's genome -- the first fruit species sequenced. They'd like to use that information to strengthen the fruit's resistance to pests so farmers can cut back on the chemicals.

10. Castor Beans

"Plants make so many things," Roger Beachy says. He points to the castor plant, whose beans make versatile oil that can be used in a wide range of products, from jet engine lubricant to shampoo. The castor bean also contains a deadly toxin called ricin that has no antidote, which explains why the crop isn't very popular to grow. Two researchers at the U.S. Department of Agriculture became the first in the world to genetically engineer castor plants, blocking ricin production as well as intense allergens that the plants make. In addition, the USDA researchers would like to genetically engineer the plant to produce castor oil epoxy, which could replace toxic solvents in paints.