Mechanical weeders were tested on both mineral and organic soils in 1995 and in 1996, to measure their impact on soil physical properties. The weeders were tested in three crops, carrots in mineral and organic soil, beans in mineral soil, and lettuce in organic soil. Soil bulk density and water content were measured at regular intervals during the weeder trial period, and samples for soil structural analysis were collected in the mineral soil at the beginning and at the end of each season. / No significant results were found in differences in mean weight diameters of dry and water-stable aggregates. Soil moisture did not vary significantly due to treatment. There was significant compaction caused by the first pass in the field (i.e., seeder) in all the crops at both sites in the 0--10 cm layer, and in some cases, to a depth of 25 cm. Additional field passes with the weeders caused some compaction in the tractor wheel at the 0--10 cm depth, and sometimes in the 10--25 cm layer, in all trials in mineral soil, yet no significant effects of treatments were detected in the trials at the organic soil site. No conclusions could be drawn as to the benefits and/or negative impacts of mechanical versus chemical weeding in mineral soil, with respect to the relative compaction caused by the mechanical weeders. This is because in this experiment spraying of herbicides did not involve tractor traffic in the field.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20280 |
| Date | January 1997 |
| Creators | Richman, Jacinda. |
| Contributors | Mehuys, G. R. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001608582, proquestno: MQ44259, Theses scanned by UMI/ProQuest. |
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