Masters Theses
Date of Award
8-1992
Degree Type
Thesis
Degree Name
Master of Science
Major
Plant, Soil and Environmental Sciences
Major Professor
John T. Ammons
Committee Members
Gary Lessman, Darwin Newton
Abstract
A study of the effects of long term management and soil morphology on distribution of soil solution nitrates and chlorides was conducted at the Highland Rim Experiment Station in Robertson County, Tennessee.
The site area was a soil fertilization study which had been under continuous corn for 28 years. Two sites were fertilized annually with 336 kg ha-1 nitrogen, 112 kg ha-1 phosphorus, 336 kg ha-1 potassium, and 56 kg ha-1 of a minor element supplement. Two other sites received this same treatment plus 10 tons/acres of manure. Two control sites were sampled in undisturbed native soils on the same landscape.
Six pedons were sampled to study spatial variability of the soil taxon. The effect of manuring and long term management on measured soil chemical properties was determined. Fourteen points in each of two plots were randomly sampled to determine distribution and quantity of soil solution nitrates and chlorides.
Field morphology included horizon designations, depth, boundary distinctness, texture, color, consistence, and structure. Observations of concretions, fossils,and other soil components were noted.
Laboratory data included total carbon analysis, cation exchange capacity, percent base saturation, pH, particle size analysis, KCl total acidity, hydroxylamine-hydrochloride manganese, citrate-bicarbonate-dithionite iron, and Mehlich I extraction of eighteen elements.
The soils in pedons 1 and 2 were classified as fine-silty, siliceous, thermic Fragic Paleudults. Pedons 3 and 8 were classified as fine-silty, siliceous, thermic Typic Paleudults. Pedons 4 and 7 were classified as fine-silty, siliceous, thermic Typic Hapludults.
Parent material generally was loess over alluvium over residuum. Movement of soil solution nitrates and chlorides was influenced by soil texture, structure, chemical composition, and the presence of pans or discontinuities. Nitrates were concentrated in the horizons above a plow pan at approximately 28 centimeters and above a paleosol at approximately 85 centimeters. The nitrates were moving laterally downslope over the paleosol.
Additions of high amounts of nitrogen had no direct correlation with soil solution nitrates. Long term additions of manure and fertilizer amendments influenced the chemical and physical composition of the soil. Total carbon was a good indicator of total nitrogen. A similar relationship was exhibited between Mehlich I extracted manganese and hydroxylamine hydrochloride extracted manganese.
Long term management did influence soil morphology. Both management and morphology had an effect on concentration and distribution of nitrates as well as other chemical components in the soil.
Recommended Citation
Branson, Janice L., "Spatial variability of soil solution nitrates and soil morphology as effected by long term management on a Highland Rim site. " Master's Thesis, University of Tennessee, 1992.
https://trace.tennessee.edu/utk_gradthes/6981