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Cover crops are commonly used to suppress weeds, manage soil erosion and prevent fertilizer runoff into waterways.

New Data Shows Increase in Cover Crops that Protect the Mississippi River

October 10, 2019
Satellite analysis finds farmers have also increased conservation tillage.

A new analysis of satellite data confirms that farmers in the Corn Belt have increased their use of cover crops and conservation tillage.

From 2006 to 2018, the acres of cover crops planted in the Corn Belt increased from 1.9 million to 4.2 million and conservation tillage increased from 49 million to 55 million acres.

Both of these agricultural practices help improve water quality in the Mississippi River because they significantly reduce the amount of nitrogen runoff from farmers’ fields.

The foundation works to align policy and market incentives to encourage farmers to adopt practices, like planting cover crops, that benefit the environment while maintaining or enhancing agricultural productivity.

In order to assess the progress of those efforts, and to understand the larger trends in agricultural production, it’s critical to have accurate assessments of how agriculture practices are changing.

This new analysis, by Applied GeoSolutions, confirms dramatic increases in conservation practices in states that are the largest contributors to excess nutrients in the Mississippi River.

Applied GeoSolutions developed the Operational Tillage Information System, or OpTIS. It uses digital satellite data from multiple sources to map and monitor cover crop development and detect crop residue left on the soil surface after planting to help determine the amount of conservation tillage on U.S. cropland.

Cover crops are commonly used to suppress weeds, manage soil erosion and prevent fertilizer runoff into waterways.

Supported in part by the foundation, Applied Geosolutions collaborated with The Nature Conservancy and The Conservation Technology Information Center (CTIC) to apply this method to assess the use of cover crops and conservation tillage across the Corn Belt. The digital satellite data was then cross checked with data from a roadside survey conducted by independent crop consultants using a mobile app.

When excess nitrogen from fertilizer used on cropland runs off into the Mississippi River, it reduces water quality for downstream communities and contributes to the dead zone of depleted oxygen in the Gulf of Mexico.

Cover crops, which farmers plant after harvesting their main corn or soybean crop in the fall, help reduce pollution in the river by retaining nutrients and soil.

Conservation tillage, which is often paired with cover crops, reduces soil erosion and runoff by limiting the amount of disturbance to the soil. Instead of tilling the soil after harvest, farmers leave the residue of the previous crop – such as corn stalks – on the field before and after planting the next crop.

The OpTIS data show a huge increase – 406% – in cover crops from 2006 to 2018 in Iowa, with the most significant surge happening from 2016-2018. While this uptick in cover crop use is highly encouraging, more work remains because only 3.34% of the 100 million acres in the Corn Belt were planted with cover crops in 2018.

Currently, some of the most comprehensive data on agricultural practices comes from the AgCensus, a survey of land use and ownership, operator characteristics, production practices, income and expenditures conducted by the USDA only once every five years.

Now, the OpTIS method can give us a big picture view of what is happening on the ground every year with a focus on what conservation practices are actually being implemented. This scientifically validated information and annual data moving forward provide an opportunity to ask and answer a variety of research questions, including:

  • Will the trend of increased use of agricultural conservation practices in the Corn Belt continue over time? How will the Midwest flooding in 2019 impact the use of cover crops?
  • Was the recent surge in cover crops in Iowa linked to any changes in policy? Or commodity prices? Or weather?
  • What accounts for differences between AgCensus data and OpTIS results at the county-level?

The answers to these questions can help advance our understanding of how and why farmers are embracing more conservation practices – and determine the best steps needed to ensure the trend continues.

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