Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 19-20). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 19-20). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1960. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 110-116).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1940. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 68-73).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1956. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 24, 2007) Vita. Includes bibliographical references.

Fertilizer and lime investigations to determine their effect upon crops and soils have been carried out at many experiment stations. The correlation of the yield, the type and the chemical composition of vegetation and changes taking place in chemical properties of soil will contribute to a better understanding of soil fertility problems. Since 1940 the Virginia Agricultural Experiment Station, in cooperation with the Tennessee Valley Authority has conducted a pasture experiment on Coeburn Silt Loam in Wise County, Virginia. Several different fertilizer treatments with and without lime, were used to evaluate their effect upon pasture vegetation. The purpose of this study is to determine the extent of and nature of the effects of certain fertilizers and lime treatments on pasture vegetation and on the soil. The experiment was conducted on Coeburn Silt Loam, a soil derived from interbedded shale and arkosic sandstone. This soil is well drained, occurs on rolling to hilly relief, is low in inherent fertility and is fairly well adapted to agricultural uses. / Master of Science

Master of Science

An investigation of the amount of exchangeable potassium found in the surface and subsoils of a 33-year rotation experiment at Blacksburg, Virginia, was made. The rotation is located on Dunmore silt loam, Which is rated as a relatively fertile soil in Virginia. There are indications that sheet erosion has removed considerable amounts of the surface soil from the steeper slopes of the first nine treatments, and it is evident that an accumulation of this material has occurred on the four lower plots. It is believed by the writer, and others familiar with these plots, that.this erosion occurred prior to the beginning of the rotation in 1909. Composite soil samples were taken from each of the 8 treatments in each of the 4 series of this rotation and resulted in a total of thirty-two fertilized subplot samples, and a corresponding thirty-two unfertilized subplot samples were collected and analyzed for exchangeable potassium. Similar analyses were ma.de on the thirty-two subsoils of both the fertilized and the unfertilized treatments. The resulting data from the surface and subsoils were then statistically analyzed and the following conclusion drawn: 1. The applications of both muriate of potash and manure significantly increased the amount of exchangeable potassium found in both the surface and subsoils. 2. The surface soils are significantly higher in exchangeable potassium than the subsoils. 3. Exchangeable potassium may be leached from the surface horizon to the subsoil when applied in a complete fertilizer in excess of plant needs. 4. Manure applications which contained considerably less potassium than the potassium added to the soils in the muriate applications, resulted in larger amounts of exchangeable potassium in the surface soils, a 30 per cent increase in crop yields, and significantly less exchangeable potassium leached to the subsoils. 5. The difference in exchangeable potassium between the fertilized subplots receiving muriate of potash. and the unfertilized subplots. resulted in an increase in the amount of potassium found in the surface soils which was equivalent to 996 pounds of 50 per cent potash fertilizer, and this figure would represent an amount equivalent to 15 per cent of the total muriate added to the surface soils. 6. The difference in exchangeable potassium found in the subsoil between the fertilized and unfertilized plots represents an equivalent of approximately 9 per cent of the total potash added. 7. Significantly larger amounts of exchangeable potassium were leached to the subsoil from plots, receiving muriate of potash than soils which received manurial treatments. Greater utilization of the applied potassium is indicated by the manurial applications. 8. A chemical analysis should be made of the manure which is applied to this experiment in order to obtain a more comprehensive understanding of the yields, and physical and chemical properties of these soils. / M.S.

An investigation of the pH, organic matter content, and cation exchange properties of the soil of the 26-year-old rotation and continuously cropped plots at Blacksburg, Virginia was carried out. Individual soil samples were taken of the eight sub-plots which represent each plot. After the chemical work had been completed, the data obtained were analyzed statistically. As a result of this investigation, the following conclusions are considered worthy of mention: Fertilizer and cropping practices which tended to increase crop yields also tended to increase soil organic matter and cation exchange capacity. There was a significant, positive correlation between organic matter content and cation exchange capacity of the soil. The organic fraction seemed to be of greater importance than the mineral fraction in contributing to the cation exchange capacity of this soil. Superphosphate, rock phosphate, muriate of potash and farm manure had or no effect on soil reaction. Ammonium sulphate caused a reduction of the pH and exchangeable calcium and magnesium and an increase in exchangeable hydrogen. The application of this fertilizer decreased exchangeable calcium but had no influence on the pH. Of the total potassium applied as muriate of potash, an average of 15 percent remained as exchangeable potassium in the upper six inches of soil. Where farm manure was applied, exchangeable calcium, magnesium, potassium, and cation exchange capacity were increased significantly. Examination of the samples and crop yield data from the check plots indicated considerable soil variation. / Master of Science