Conservation agricultural systems have a long history of development and use in the southeastern United States, but they are still not the norm on the landscape. Literature from the region suggests that a diversity of soil properties can be improved with cover cropping and conservation tillage, but results are not always consistent. Our objectives were to (a) review recent research on conservation tillage and cover cropping in the region and (b) compile and synthesize recent data from a diversity of farms along a conventional to conservation gradient. As part of recent on‐farm trials focused on soil N availability, we analyzed soil organic C and N fractions and routine soil nutrient characteristics from a total of 196 fields in corn (Zea mays L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.) production in three physiographic regions of the Coastal Plain (n = 71 fields), Piedmont (n = 77 fields), and Appalachians (n = 48 fields) in North Carolina, South Carolina, Pennsylvania, and Virginia. These data allowed us to establish first estimates of threshold optima for soil organic C and N fractions and other inorganic nutrients. On‐farm data confirmed the literature review that conservation tillage resulted in greater stratification of soil organic C and N and nutrient concentrations. Soil health improvement could be inferred along the gradient from inversion tillage to no tillage without cover cropping to no tillage with cover cropping. This collection of recent literature and on‐farm data can be a useful starting point for establishing target limits and assessing soil health conditions on farms in the region.

Cereal yields tend to be higher in cereal–legume rotations relative to cereal monoculture yields. We investigated the influence of crop rotation on yield and input‐use efficiency in high‐yield irrigated maize (Zea mays L.)‐based cropping systems using producer‐reported data from western U.S. Corn Belt (about 11,000 observations). Across regions, average yield of maize grown after soybean [Glycine max (L.) Merr.] (S–M) was 0.2 to 0.6 Mg ha⁻¹ (2–5%) higher, relative to yield of maize grown after maize (M–M). Soybean yield was 5% greater after two consecutive maize crops (M–M–S) than after only 1 yr of maize (S–M–S). Nitrogen fertilizer rate in maize fields was 13 kg N ha⁻¹ (6%) lower in S–M than M–M fields, which, together with higher maize yields in S–M fields, resulted in 11% higher nitrogen partial factor productivity (PFP_N). Difference in PFP_N was unrelated with residual soil N–NO₃⁻ from prior crop. Analysis of rotation data indicated that rotation effect persists across a wide range of maize yields, from 6 to 15 Mg ha⁻¹, though magnitude of rotation effect decreases with increasing yield level. Trends toward greater proportion of total maize area in S–M, rather than M–M, accounts for 8% of maize yield gain in U.S. Corn Belt since 1970. Similarity between our findings and previous research highlights the opportunity to quantify impact of management on yield and efficiencies by using producer data as a complement to high‐cost multi‐year, multi‐site field experiments.Core Ideas We assessed rotation effect on on‐farm yield and input‐use efficiency. Analysis was based on a large producer‐reported database collected from high‐yield irrigated maize–soybean systems. There was a consistent positive rotation effect on yield and partial factor productivity for N fertilizer. Number of previous maize crops did not affect maize yield in monoculture but soybean yields were higher following multiple maize crops. Increasing maize area in rotation relative to monoculture accounts for 8% of the maize yield gain in the U.S. Corn Belt since 1970.