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How do GM crops impact soil health?

 

With 2015 named the International Year of Soils by the Food and Agriculture Organization, we’re starting the year off with a post about GM crops and soil health – is there a relationship?

GM crops can actually help keep agricultural soils healthy and productive.

Healthy soils are the foundation of a healthy agricultural production system. From serving as a biodiversity powerhouse to contributing to carbon sequestration, agricultural soils are an important component of food production.

Weed Management & Conservation Tillage

Weed control is a constant problem that farmers of all production methods must manage to have healthy, high-yielding crops. One way farmers control weeds in their fields is through tillage – which is to literally turn over the top layer of soil to uproot the weeds. While this is one solution for weed control, it leaves a field open to erosion and run-off to waterways, and releases carbon dioxide, a contributor to greenhouse gases.Herbicide tolerant GM crops enable farmers to till less often, leading to improved soil health and water retention, reduced runoff, and reduced greenhouse gas emissions. The organic matter and moisture that remains in the soil helps crops better withstand periods of drought, and less erosion means that the inputs farmers use stay in place and don’t end up in our lakes and rivers.

Photo courtesy of USDA Natural Resources Conservation Service.

According to Director, University of California Systemwide Biotechnology Research and Education Program, Martina Newell-McGloughlin, "Biodiversity is actually enhanced by the adoption of GM crops. Those crops commercialized to date have reduced the impacts of agriculture on biodiversity through enhanced adoption of conservation tillage practices … and use of more environmentally benign herbicides and through increasing yields to alleviate pressure to convert additional land into agricultural use."

These five facts from CropLife International will give you a new appreciation for the soil beneath your feet.

  1. Soil is an important carbon sink storing 10% of the world’s carbon dioxide – more than all terrestrial vegetation and the atmosphere combined. When soil is disturbed, or tilled, carbon dioxide is released into the atmosphere where it is a major contributor to global warming.
  2. No-till agriculture keeps carbon in the soil and because it requires fewer field passes it uses less fuel than tillage. In 2012 alone, the amount of CO2 saved by using herbicide tolerant biotech crops - that help facilitate no-till - was equal to removing every single car from the streets of London for five years!
  3. It can take more than 500 years to form two centimeters of topsoil – the outermost layer of soil, which has a high concentration of nutrients and is crucial for crop growth. Avoiding soil disruption helps keep this top layer healthy and productive.
  4. Soil is home to billions of living microorganisms which recycle organic material to maintain soil fertility and support plant growth. One cup of soil may hold 7 billion bacteria – the equivalent of our world’s human population!
  5. Globally, up to 50,000 square kilometers of topsoil – an area around the size of Costa Rica – is lost every year mainly due to wind and water erosion. By using herbicide tolerant crops, farmers don’t need to till the soil to remove weeds so soil retains its structure and erosion is reduced.

You can read more about how herbicides used with herbicide resistant crops interact with microbial communities in agricultural soils here. Additionally, it is important to note that GM crops do not adversely affect soil biodiversity, as explained in this response. Extension specialist Shawn Askew also addresses whether herbicide resistant crops contribute to higher usage of herbicides in this response. Learn more about herbicide use with GM crops here and here.


 

 

Looking for more information about soil health? Check out these resources: