The U.S. Department of Agriculture’s (USDA) Natural Resources Conservation Service (NRCS) evaluates conservation trends and effects on cultivated cropland through the multiagency Conservation Effects Assessment Project (CEAP), a sampling and modeling approach using natural resource data and farmer surveys.
The first set of farmer surveys was conducted in 2003–06 (CEAP I) with reports released from 2010 through 2014. Now, comparison data from farmer surveys conducted in 2013–16 (CEAP II) make it possible to estimate conservation adoption and effects between the CEAP survey periods.
Between the CEAP surveys, increased demand and higher prices for commodities encouraged production expansion in nearly all regions of the country. A warming climate, longer growing season, and advances in seed technology and higher-yielding crop varieties drove cropping pattern shifts, most notably in the northern and southern plains, where corn and soybean production replaced wheat and other close-grown crops with lower average nutrient needs, and fallow periods.
During the decade, CEAP found that:
- Farmers increasingly adopted advanced technology, including enhanced-efficiency fertilizers and variable-rate fertilization to improve efficiency and benefit rural economies and the environment;
- More efficient conservation tillage systems, particularly no-till, became the dominant form of tillage, reducing erosion and fuel use;
- The use of structural practices increased, largely in combination with conservation tillage as farmers integrated multiple conservation treatments to gain efficiencies.
- Conservation crop rotation and cover crop use increased, as did the use of high-biomass crops in rotation;
- Irrigators shifted toward more efficient pressure-based systems, and improved water management strategies decreased per-acre water application rates.
As a result, CEAP estimates:
- Average annual water (sheet and rill) and wind erosion dropped by 70 million and 94 million tons, respectively, and edge-of-field sediment loss declined by 74 million tons;
- Nearly 26 million additional acres of cultivated cropland were gaining soil carbon, and by CEAP II carbon gains on all cultivated cropland increased by over 8.8 million tons per year;
- Nitrogen and phosphorus losses through surface pathways declined by 3 and 6 %, respectively. However, subsurface nitrogen and soluble phosphorus losses increased by 13 and 11 %, respectively;
- Per-acre irrigation application rates dropped by 19 % and national withdrawals by 7 million acre-feet;
- Average annual fuel use dropped by 110 million gallons of diesel fuel equivalents, avoiding associated greenhouse gas emissions of nearly 1.2 million tons of carbon dioxide equivalents.
“This latest CEAP report shows that farmers have done an outstanding job over the years in using innovative conservation strategies that help mitigate climate change,” said NRCS Chief Terry Cosby, “But we have more work to do. Reports like this one help us better understand conservation approaches and make improvements to increase positive impacts. This report will help steer our conservation efforts well into the future to help us adapt to changing trends in production, climate and technology.”