Long-term Tillage: Effects on Soil Carbon, Nitrogen, and Yield; University of Nebraska Lincoln

The site was in native short-grass prairie until 1969. The prairie was
grazed by cattle and wildlife. Soil parent material is alluvium mixed
with aeolian deposits. It has been cropland now for 25 years. The
current land use and treatments are Winter wheat-fallow rotation,
Treatments are no-till, stubble mulch tillage and moldboard plow
tillage. There are at least 3 replicates in the experiment. The
experiment has a randomized plot design. There are control plots
described as follows: Native sod plots serve as the controls. These
plots have not been grazed so plant composition has changed. Staff
recently implemented a 5 year burn schedule to return the plots to a
more native state.

Average climatic conditions at the experimental site:

Minimum annual temperature: -3.9 deg C
Mean annual temperature: 9.1 deg C
Maximum annual temperature: 22.6 deg C
Minimum annual rainfall: 230 mm
Mean annual rainfall: 440 mm
Maximum annual rainfall: 520 mm

Soil properties at the experimental site:

Depth of root limiting layer: No root limiting layer
Approximate soil organic matter content: 2.3%
Approximate carbon:nitrogen ratio: 12.4
Approximate soil bulk density: 1.1 g/cm3
Percent clay (i.e. particles less than 2 um): 23%
Percent silt (i.e. particles between 2 um and 50 um): 37%
Percent sand (i.e. particles between 50 um and 200 um): 40%
Approximate minimum soil pH: 7.4

Nearest meteorological station to the site: NE14 which is 1.6 km from
the site at coordinates 100deg.45min. West, 41deg.14min. North The
meteorological station is automatic.

EXPERIMENTAL DESIGN

Details of the plots
Width of smallest plot is 8.5 m
Length of smallest plot is 45.7 m
Slope: 0.1% . Shape: Uniform
Details of direction of cultivation: E-W, parallel to long-axis
Width of Bare Strip around plot: 2m

This information was compiled for the GCTE-SOMNET Database, Pete
Smith, Pete Falloon, David Powlson, and Jo Smith. Soil Science
Department, IACR-Rothamsted, UK.