Masters Theses
Date of Award
3-1983
Degree Type
Thesis
Degree Name
Master of Science
Major Professor
D. E. Reichle
Committee Members
H. R. DeSelm, D. A. Lietzke
Abstract
Two- and ten-times the annual ambient inputs of both sulfate (S0=4) alone and hydrogen (H+) plus sulfate (acid-sulfate) were applied at five week intervals to the forest floor of Walker Branch Watershed. Over a 14-month period, densities of litter macroarthropods averaged 19% lower in the high sulfate treatment compared to the control. Soil arthropod populations increased significantly in response to the low sulfate and to both acid-sulfate treatments. Fungivores and predators in the soil and litter exhibited responses similar to those observed in the total populations.
The treatments produced chronic and apparent acute effects on forest floor arthropods. Chronic effects on litter macroarthropod populations were observed in the high sulfate treatment. Treatment effects on litter populations were especially severe during late summer and early autumn, normally a time of environmental stress caused by low soil and litter moisture.
Graphical inspection revealed apparent acute treatment effects in June 1981 and January 1982 when arthropod sampling took place three to seven days after treatments were applied. In both months, the low sulfate treatment increased soil arthropod densities while both ten-times treatments decreased densities compared to the control.
The chronic effects of the high sulfate treatment probably resulted from the large potassium (K) additions to the forest floor (438 kg • ha-1 • yr-1). Potassium sulfate was used in the sulfate applications. The apparent acute effects of both ten-times treatments also probably resulted from concentrated additions of K to the forest floor. The overall positive response of soil mesofauna to the high acid-sulfate and to both two-times treatments may be due to the fact that small additions of K fertilizers have a beneficial effect on forest floor arthropods (Hryniuk 1962, Gary et al. 1971). Soil arthropods were not adversely affected by the hydrogen ion additions probably because most of the H was buffered by the litter.
The treatments may have indirectly affected forest floor arthropods by influencing microfloral activity. Respiration measurements taken in the litter showed that evolution of carbon dioxide was 26% less in the high sulfate treatment than in the control.
Analysis of soil nutrients showed increased levels of K and S04 corresponding to the low and high times treatments. Soil pH, aluminum (Al), and available phosphorus (P) appeared unaffected by the treatments. Soil pH was unaffected by the acid-sulfate treatments because most of the additional H was neutralized by the forest floor. Analysis of litter leachate during a single treatment interval indicated that only 31% of the H applied in the high acid-sulfate treatment reached the mineral soil. Thus, even after 18 months of treatments, the forest floor litter still served as an excellent buffer against large increases in H inputs to the soil environment.
Recommended Citation
Craft, Christopher Bruce, "Hydrogen and sulfate additions to the forest floor and their effects on soil and litter anthropods. " Master's Thesis, University of Tennessee, 1983.
https://trace.tennessee.edu/utk_gradthes/14781