An experiment was carried out on the University of British Columbia farm dealing with the use of calcium cyanamide (known commercially as "Aero Cyanamid, Granular" or "Cyanamid”) as a weedicide and fertilizer under British Columbia coast conditions. Three rates of Cyanamid and a Control consisting of a 4 - 10 - 10 fertilizer treatment were tested in conjunction with two times of application. On a four by two factorial arrangement, this resulted in eight distinct treatment combinations, each of which was replicated three times in randomized blocks. The planting plan was duplicated for the two vegetables, carrots and turnips. Weed control in the plots was observed, yield of carrots and turnips taken, and nutritional value of the vegetable assessed on the basis of chemical analyses. Several interesting relationships were revealed under the conditions of the experiment. The response of the two vegetables to the treatments was similar for some of the factors studied and different for others. The time of Cyanamid application was found to be of great significance. Its effect was manifested in the weed control study, and in the yield and nutritional value of carrots and turnips. The degree of weed control was increased by increments of Cyanamid. Pre - emergence applications resulted in better weed control than did pre - planting applications. Best yield of carrots and turnips resulted from the use of the 300 lb. Cyanamid per acre, pre - planting treatment. Pre - emergence applications (300 and 500 lb. Cyanamid per acre) killed many young carrot and turnip plants, thereby decreasing yield. Increments of calcium cyanaxaide increased the protein content of carrots and turnips. The root/top ratio, titratable acidity, and carotinoid pigment content values showed no significant differences as a result of the treatments. Cyanamid treatments in general, as compared to the Control treatment, tended to increase the total soluble solids and vitamin C values, but tended to decrease the dry weight, ash weight, and conductivity values. Pre - emergence treatments, as compared to pre - planting treatments, tended to increase weed control, ash content, conductivity values, and protein content, but tended to decrease yield. The results of this experiment indicate that calcium cyanamide is an effective weedicide and fertilizer when properly used. / Land and Food Systems, Faculty of / Graduate

Thesis (M.S. - Plant Protection)--University of Arizona, 1985. / Includes bibliographical references (leaves 34-36).

Graduation date: 1991

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Atrazine has been one of the most successful herbicides used both in agriculture and in urban situations. Its use has now been banned in U.K. agriculture. Atrazine applied to agricultural soils has been shown to leach down the profile with residues remaining in the soil up to 9 years after initial application. Residues are frequently found in sub-soils and aquifers world wide. In this study, systems were developed that enabled sampling and incubation of intact sub-soils cores that contained a sub-soil atmosphere. The sub-soil represents the last zone of significant potential degradation of xenobiotics, such as atrazine, as leaching into deeper soils and ground waters occurs. Conditions prevailing in these soils are different in terms of soil atmosphere, structure and activities of the soil microbial community. Laboratory studies were carried out which investigated the rate of atrazine mineralisation in intact sub-soil cores. Soil cores were aerated with either laboratory air or CO2-rich air generated through soil microbial activity from within a sealed sub-soil air reservoir. Results showed that atrazine mineralisation occurred at significantly higher rates in sub-soil cores aerated with sub-soil air compared to the rates in sub-soil cores aerated with laboratory air. Studies comparing mineralisation rates in intact sub-soil cores, incubated under sub-soil air or labroatory air, and soil biometers, containing sieved, mixed sub-soil, showed that higher rates of atrazine mineralisation occurred in the biometer studies than occurred in intact sub-soil cores. Similar studies using intact top-soil cores showed higher rates of mineralisation. Investigations carried out using intact sub-soil cores amended with a range of glucose concentrations, showed that no difference occurred in glucose mineralisation rates between soil cores aerated under sub-soil air and under laboratory air.