Date of Award
Master of Science
Plant, Soil and Environmental Sciences
F.F. Bell, L.N. Skold
The purpose of this study was to measure certain physical and chemical characteristics at different depths in the profile of a Memphis silt loam soil. These characteristics were considered in detecting potential "traffic pans." The experiment included six tillage treatments. The effectiveness of the six tillage treatments in the mixing of lime and fertilizer was also evaluated.
The experiment was conducted at the Milan Field Station for five years (1968-1972). A randomized complete block design was used. The six treatments were break 6 inches, break 9 inches, break 12 inches, offset disc 6 inches, chisel 14-16 inches and bedding 6 inches. Cotton was grown each year and yields collected from all plots. Rainfall data was available in Climatological Data, U. S. Department of Commerce.
Core samples and bulk samples were obtained in the spring of 1972 from the tilled zones and immediately below the tilled zones of each treatment. Bulk density, large and small pore space, pH, available phosphorus and potassium were determined on all zones sampled.
There were no significant differences in bulk density among the treatments or depths and no distinguishable "traffic pan." A compacted layer was detected using a soil sampling probe in the break 6 inch and offset disc 6 inch treatments. Some one-inch cores were taken in the most compact layers of these treatments and their bulk densities were somewhat higher than the bulk densities of three-inch cores taken from the same treatment. It was concluded that the densest layers were masked to some extent in the three-inch cores.
There were differences in the mixing of lime and fertilizer among treatments, but the differences did not show up in yield response.
No significant differences in yield among treatments were observed in any of the years studied.
The rainfall data was considered for each year. None of the growing seasons studied had serious deficiencies in rainfall.
Parks, Stephen Mooring, "Some effects of six annual tillage treatments on certain physical and chemical properties of a Memphis silt loam soil after four years in cotton production. " Master's Thesis, University of Tennessee, 1973.