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Organic Farms Use Plastic Mulch For Weed Control; 1 Solution Is Controversial : The Salt : NPR

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Lisa Elaine held

At One Straw Farm, an organic farm in northern Baltimore, lettuce sprouted in rows of plastic covering the ground. Although traditional farmers also use plastic mulch, organic farms like One Straw rely more on this material because they must avoid chemical herbicides, which are prohibited by organic herbicides.

At One Straw Farm, an organic farm in northern Baltimore, lettuce sprouted in rows of plastic covering the ground. Although traditional farmers also use plastic mulch, organic farms like One Straw rely more on this material because they must avoid chemical herbicides, which are prohibited by organic herbicides.

Since 1983, Drew and Joan Norman have been producing organic vegetables on 60 acres north of Baltimore.

It's everywhere: seedlings in the greenhouse are waiting to be transplanted, asparagus is ready to be picked, small leaves of red and green leaf lettuce sprout from the ground-each field is covered with rows of plastic.

Nowadays, plastics are under attack because of the environmental problems they cause. However, sustainability-conscious shoppers may not know that many organic farmers (such as their traditional agricultural neighbors) also rely on plastic. It is spread on the ground in the form of mulch to suppress weeds, save water and help plants grow.

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At One Straw, plastic film, which occupies only 30 acres of production area in one year, will extend 36 miles in a straight line. Larger organic operations, such as

, Has farms in Pennsylvania, Georgia and Florida, spreading them on thousands of acres of land. When the season is over, it will eventually enter the landfill.

Many organic farmers hope to find a substitute for plastic, but they say there is no such thing yet. One possible solution, namely biodegradable plastics, is not allowed in the current form of organic regulations, although some people think that these regulations should be changed. Others worry about the long-term effects of biodegradable plastics on soil health and the environment.

"We are looking at it with a larger eye,'Is it being biodegraded?' We need to make sure that what we put in the soil will have a positive rather than a negative impact,"

, Advising the U.S. Department of Agriculture on organic regulations.

The flat plastic is spread across the fields with huge rollers and is held down by the soil, preventing direct sunlight from hitting the ground and stimulating the growth of weeds. In this way, plants like tomatoes can grow unhindered in the perforated plastic bags of tomatoes. Although traditional farmers use this material, farmers of organic agricultural products rely more on it because they must avoid chemical herbicides, which are prohibited in organic chemical planting.

"The most difficult part about organic [agriculture] is weed control," said Larry Tse, the manager of the farm.

In the Hudson Valley area of ​​New York, weeds grow rapidly due to fertile black dirt. Tse used plastic mulch on all farm produce beds and helped nearby farms lay plastic on their fields.

In addition to controlling weeds, plastic can also be used well with drip irrigation. The system can deliver water directly to the roots of plants through a network of thin plastic pipes winding under the mulch, thereby saving water. One Straw Farm's Drew Norman (Drew Norman) said: "Compared with the use of sprinklers, the water savings per gallon acre is about 60%."

This plastic also moderates soil temperature by increasing farmers’ yield and season length. “We use plastic mulch on all the land,” says Tom Beddard of Lady Moon Farms, a large organic grower of supermarket vegetables. "This is to control weeds and soil warmth, and love crops (such as tomatoes, peppers and eggplants) will mature bare on the plastic ground a few weeks ago."

However, there is also the problem of waste. Both Tse and Beddard said that they have found that the company recycles its agricultural plastics in a short period of time in the past, but the operation has never lasted long. Instead, at the end of the season, the vast majority of plastics are lifted from the ground and put into trash bins, and then transported to the landfill, which brings huge cost and labor challenges to farmers. In addition, Drew Norman said that work may interfere with other tasks, such as planting cereals and legumes to "cover crops" in the fall to protect and strengthen the soil during the winter.

This is why so many farmers want alternatives. Although there are natural mulches that decompose in the soil, such as straw and paper, they are too costly or labor intensive for many farmers. However, if the plastic mulch can slowly degrade throughout the season, disappear into the fields and eliminate waste, it would be an ideal solution.

However, at present, organic farms do not have such a solution because all biodegradable plastic coverings on the market contain petroleum-based materials. In 2014, the National Organic Program (NOP) of the United States Department of Agriculture that enforces and monitors organic regulations stipulated that any biodegradable mulch can only be used if it is 100% "bio-based" (that is, made entirely of plant materials) .

Since then, a U.S. Department of Agriculture spokesperson said in response to e-mail questions that since then, the U.S. Department of Agriculture has received "considerable feedback" from organic farmers and mulch mulch manufacturers. According to the spokesperson, two researchers gave speeches on this topic at the last NOSB meeting in April 2019, and farmers expressed continued interest.

Agricultural chemical giant BASF has been sending representatives to the NOSB meeting, arguing that its product Ecovio is a certified organic farming product, which is a biodegradable plastic covering commonly used by farmers all over the world. it says

The product released in 2018 shows that the product is completely biodegradable.

Jennifer DeBruyn, associate professor of biological systems engineering and soil science at the University of Tennessee Agricultural Research Institute, said that although this study was supported by BASF, other independent studies have reached similar conclusions. She said: "Our main conclusion is that we believe that these mulches will not have a strong impact on soil health parameters, soil health indicators or soil microbial communities."

Her team recently posted it as


But so far, the team has only analyzed two years of field trials. DeBruyn said: "In many cases, soil parameters may take years and years to change and change. Therefore, I think there will be many questions about the long-term impact."

Behar said that at present, the hesitation around the unknown long-term impact is undertaken by the members of the NOSB, although the topic has been included in the board's work agenda for 2019. She also hopes that the company will be able to use the synthetic bio-based covering for the market-behaves like plastic but does not contain any petroleum-based materials, so it will be approved for use in organic agriculture. She believes that, based on public comments at the NOSB meeting, this situation is imminent.

At the same time, the tomato plants are getting taller this season, and the Normans don’t want to wait for another season to allow the use of available biodegradable mulch, even if they contain oil. Joan Norman said: "There is no doubt that it will be 100% bio-based at some point, and we are looking forward to it." "But until that point... it's definitely better than filling plastic garbage in a trash can. The buried site is better. This is a lot of plastic."


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