유기농 텃밭이 건강이 아니라 환경에 훨씬 좋다

A startling, upsetting study — at least for many organic farmers and gardeners — was published in the September issue of Annual of Internal Medicine. It was quickly followed by an avalanche of coverage in the national media, with headline similar to the following: “Stanford scientists cast doubt on advantages of organic meat and produce,” (New York Times) and “Organic food no more nutritious than non-organic,” (Business & Financial News).

Could it be true? For many organic aficionados, it is a no-brainer that organically grown food is safer and healthier than conventionally grown food, that is, food grown using chemical fertilizers (aka artificial or synthetic) and inorganic pesticides.

A four-year meta-analysis statistical study of 237 peer-reviewed research studies over the past four decades by Stanford University scientists comparing organic and conventionally grown food, including not only fruits and vegetables, but also grains, meat and dairy products, found little difference between the two. This column is limited only to its findings about fruits and vegetables.

The bottom line: Organically certified fruits and vegetables, on average, were no more nutritious than their conventionally grown counterparts. Also, conventionally grown produce was not any more likely to harbor dangerous bacteria, such as E. coli, than organically grown fruits and vegetables.

While 38 percent of conventionally grown produce contained traces of pesticides and organically grown produce contained a mere 7 percent detectable residue, both easily meet the Environmental Protection Agency’s percentage of pesticide residue allowable. The 7 percent of pesticide residue on organically grown food can be attributed to pesticide spray drift from conventional farmers, and possible contamination during processing and transporting organic food along with conventional produce.

You can bet your back forty that organic farmers and backyard organic gardeners have been quick to challenge the Stanford findings. one challenge was that it did not look at environmental effects of how farming is done. Environmental impacts of farming methods were not within the parameters of the study.

Why bother to garden organically?

Although many pesticides have been banned after having been found to be dangerous to the environment, there are still pesticides in use that organic growers are challenging the EPA to take a closer look at. There is also an ongoing debate about the safety limits of pesticide residue set by the EPA. And misused chemical pesticides and fertilizers continue to contaminate our lakes, rivers and groundwater, although less so than in the past.

Safety measures for farm workers who do the spraying and harvesting have been greatly improved in recent years, but there are still concerns over how current use is affecting farm workers’ health over years of exposure. And there is the same concern about the consumer’s health.

Organic farmers contend that their practices are sustainable, while conventional farms are far from it as they depend heavily on synthetic chemical fertilizers and pesticides. Both are made largely from petroleum and natural gas, which are not renewable. Conventional farms produce up to 40 percent more greenhouse gases per acre than organic farms, plus organic farms use 45 percent less energy in producing their crops.

Artificial fertilizers, which conventional farmers are heavily dependent upon, are available as nutrients that are ready to use soon after application. Organic fertilizers, such as compost and fertilizers made from animal manures, must first be changed to a form that plants can use.

This process is accomplished by microbes, earthworms and other macro-microbes digesting organic matter that is then recycled back into the soil and slowly releasing its nutrients that are then available to plants over time. In the process, these hardworking underground creatures are also largely responsible for building good tilth and soil structure.

But synthetic fertilizers do nothing to build structure. They are available in the soil for a very limited time before they are either used or left below the root zone, while organic fertilizers remain available to plants for a much longer time. Chemical fertilizers and pesticides can be hazardous to soil micro- and macro-ogranisms — they often decrease their numbers significantly.

Break your garden’s chemical dependence

Research has shown that home gardeners use more chemical pesticides and fertilizers per acre than do conventional farmers. To put it mildly: Many of us inadvertently add greatly to the polluting of our soil, rivers, lakes and groundwater.

In 2013, we can do our part in reducing the use of pesticides and fertilizers that add to the contamination of our environment. Following are just three things that you can do in your gardening next year to improve your gardens and the environment:

• Grass-cycle your lawn cuttings back into the turf by using a recycling lawn mower, which cuts the blades into fine particles and then sifts them down to soil surface where microorganisms soon recycle them back into nitrogen and organic matter sources. A lush and healthy lawn crowds out most weeds, and the few weeds that do pop up can be hand-dug. If you still feel the need to fertilize, use an organic lawn fertilizer.

• Further help to eliminate the use of pesticides by making the good-guy insects welcome in your ornamental beds and vegetable garden. These insect predators and parasites will dispatch most of the bad bugs before they can do much harm to your gardens. Insect predator and parasites will be attracted to your gardens by planting plenty of flowers since at one stage or another of their lives, they feed on pollen and/or nectar. Although some of these insects can be purchased as eggs, in most cases you won’t need to buy them — just provide for their needs and they will come.

• Compost: This seemingly magic potion does double duty — it works as a soil amendment that nourishes the soil, plus there is good evidence that compost also helps fight soil-borne diseases. If you don’t have time, room or resources for a compost pile, look for bagged compost at garden center. But if you choose steer compost, use it sparingly. It’s the most common compost found at most garden centers, but it is usually high in salts that will burn your plants if you apply it too generously.

You will think of additional ways to eliminate, or at least limit, the use of artificial pesticides and fertilizers in your gardens next year. In the meantime, have a joyous Christmas and plan to do your part in working for a healthier planet Earth in 2013.