Effect of tillage system on growth, maturity and yield of corn and soybean

This experiment was initiated in 1976. In the previous years
(1955-1975), the site had corn/soybean production with annual
moldboard ploughing. It is estimated that between 1880-1955 there
was mixed forage/grain production, ploughed two years in every five.
Before 1880 the site was in native prairie
grass.

Rotations used in this experiment are continuous corn, corn after
soybean, soybean after corn and continuos soybean. Treatments are the
same on all rotations and are: 1) moldboard plough and secondary
tillage, 2) Chisel plow and secondary tillage, 3) Ridge-plant and 4)
No till plant

SOIL CHARACTERISTICS OF THE SITE

a) Soil description

Chalmers silty clay loam fine-silty, mixed, mesic Typic Haplaquoll.
Mollisol.

A and Ap - high O.M. content - developed in loess. Depth to 38cm. Bt and
BC - significant swelling cracking
clays. Prismatic structure grading to Blocky structure (primary) to
96cm. 2C - Glacial till and outwash.

b) Soil properties

Depth of root limiting layer: No root limiting layer
Approximate water holding capacity: 30 mm per 1000 mm
Approximate minimum cation exchange capacity: 20 mmol/kg
Approximate maxiumum cation exchange capacity: 25 mmol/kg
Approximate minimum soil organic matter content: 4%
Approximate maximum soil organic matter content: 6%
Approximate minimum soil bulk density: 1.3 g/cm3
Approximate maximum soil bulk density: 1.4 g/cm3
Percent clay: 32%
Percent silt: 59%
Percent sand: 9%
Approximate minimum soil pH: 6.1
Approximate maximum soil pH: 6.7
Method of determining soil pH: pH measured in water

MEASUREMENTS MADE DURING THE
EXPERIMENT

a) Vegetation measurements made and frequency

Yield: Yearly
Total dry matter offtake: Yearly

b) Soil sampling

Time zero soil measurements taken. Sampled in corn after harvest.
Represents 32 sub-samples with a soil probe to a depth of 20
cm. Measurements = pH, P, K. Samples not stored, OM first sampled in
1981. Details of soil sampling method: Subsamples taken with a 2 cm
wide soil probe, 20 subsamples/plot to 1981, 11 subsamples/plot
1985-1994, All 64 plots in 1981 and 1994. Selected plots in 1985. Soil
is separated into layers. Details of measuring depths and soil layers:
1981: Soil separated as follows: 0-7.5, 7.5-15, 15-22.5, 22.5-30
cm. 1985 & 1994: Soil separated as follows: 0-5, 5-10, 10-15, 15-20
cm.

c) Soil measurements made and frequency

Total carbon: Twice in 1981 and 1994
Method of measuring total carbon: Determined by
Melbius or Walkley-Black procedure.
Soil bulk density or weight: Twice in 1981 and 1994.
Method of measuring soil bulk density or weight: Troxler SC-120H
Surface Density Guage (radioactive source)
Other nutrients: pH, P and K

d) Details of the meteorological station

Nearest meteorological station to the site: West Layafette 6 N'W
which is 2 km from the site at coordinates 87deg.0min. West,
40deg.28min. North. The meteorological station is automatic.

e) Meteorological data available and frequency

Rainfall: Daily
Air temperature: Hourly
Soil temperature: Daily at under grass at 10cm, under bare soil at
5, 10 and 20cm. depth
Wind speed: Continuous
Net Radiation: Hourly
Sun hours: Continuous
Relative humidity: Continuous

EXPERIMENTAL DESIGN

a) Details of the plots

Width of smallest plot is 9.1 m
Length of smallest plot is 31.6 m
Slope: 0-2% . Shape: Concave
Details of direction of cultivation: Parallel to long-axis of plot
Width of Bare Strip around plot: 0.76m
Width of Discard Strip around plot: 3m

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