Counting Cover Crops
New National Wildlife Federation report provides overview, success stories of cover crop use in the United States today.
Lara Bryant, Ryan Stockwell and Trisha White
Cover crops – non commodity crops grown to protect soil in fallow fields – hold great promise to improve soil health and productivity, reduce input costs, improve yields and increase forage availability. Cover crops also provide public benefits by improving water quality, air quality and wildlife habitat. Recognizing these benefits, farmers have been increasingly using cover crops while agriculture agencies are refining policies to encourage more cover crop adoption.
In order to fully demonstrate the impact of increased cover crop use, we need baseline data and sound methods for tracking growth. How many more farmers are using cover crops, and on how many more acres of farmland? Can we measure the benefits in tons of topsoil and nitrogen kept on fields? Can we measure the savings to municipalities for providing water quality? Having these numbers would make the case for additional support for cover crops.
Unfortunately, we know very little about just how many acres are currently planted to cover crops. Since 2000, a handful of studies have attempted to calculate the acreage, but each of these have been regional in scope and have used a range of different methodologies. Using data from seed dealers cross-checked with statistics from the National Agricultural Statistics Service (NASS), we estimated that the total acreage of cover crops in the Mississippi River Basin (MRB) in 2011 was between 1.8 and 4.3 million acres, less than 2% of total cropland area.
We hope our research will inspire discussion and catalyze more efficient, long-term efforts to track the adoption of cover crops. Our estimates are in line with those from earlier studies, but the range is too great for effective calculation of cover crop benefits. Our methodology utilized the best available data, but is limited by uncertainties about sample size, scale and reproducibility.
Reliable baseline estimates of cover crop adoption can provide a starting point for measuring future changes. In the future, decision makers will require improved tracking of cover crop planting in terms of land area, in order to better determine the effect of increased cover crop use and inform policymaking.