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UBC Theses and Dissertations

Calcium cyanamide as a weedicide and its influence on the nutritive value of carrots and turnips Mohr, Willard Phillip


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.

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