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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Characterization of the movement of spray drift past a shelterbelt

Peterson, Jonathan Christian 29 April 2008
Pesticide use is an important component of the agricultural industry. Pesticides are typically applied to crops as a droplet spray, and these droplets are susceptible to off-target movement due to wind, which is called spray drift. It has recently been recognized that shelterbelts may protect vulnerable downwind areas from spray drift. There is a need to characterize the movement of spray drift past a shelterbelt to better understand the extent of this protection and the variables which affect it. The variables investigated in this research may be classified as meteorological conditions, spray application settings, and shelterbelt properties.<p>This research investigated the movement of spray drift past a 5 m tall carragana/chokecherry shelterbelt. Spray was applied using a conventional sprayer that travelled on a path that was upwind and parallel to the shelterbelt. A tracer substance was mixed into the spray solution, and the deposition and airborne concentration of drift was measured using a variety of collectors placed at perpendicular distances up- and downwind of a shelterbelt. The mass of drift deposit on the collectors was determined using spectrofluoremetry and standard solutions.<p>When the spray swath was a distance of 3H (where H is the height of the shelterbelt) upwind of the shelterbelt, it was found that the ground deposition of drift at a distance of 0.5H downwind of the shelterbelt was reduced by approximately 74%, compared to the drift deposit at 0.5H upwind. The reduction over the same downwind distances was 29% in the open field setting. The airborne drift cloud was attenuated by the shelterbelt and the airborne concentration of drift exiting the shelterbelt was reduced by approximately 85% of the entering drift. The airborne drift concentration profile indicated that there was a greater proportion of drift travelling over the top of the shelterbelt rather than passing through the shelterbelt, with the peak concentration occurring at approximately 1.2H.<p>Qualitative and multiple linear regression analyses were used to determine the significance of a number of meteorological and controlled variables on the deposition of drift. It was found that the mass of drift deposited downwind of the shelterbelt increased with a higher wind speed, higher temperature, and lower relative humidity. For the range of meteorological conditions sampled, the effect of wind direction and atmospheric stability were found to be insignificant. Finer spray qualities and higher shelterbelt optical porosity produced greater airborne drift and deposition downwind of the shelterbelt. With increasing upwind sprayer distance, the mass of drift deposited within the shelterbelt decreased.
2

Characterization of the movement of spray drift past a shelterbelt

Peterson, Jonathan Christian 29 April 2008 (has links)
Pesticide use is an important component of the agricultural industry. Pesticides are typically applied to crops as a droplet spray, and these droplets are susceptible to off-target movement due to wind, which is called spray drift. It has recently been recognized that shelterbelts may protect vulnerable downwind areas from spray drift. There is a need to characterize the movement of spray drift past a shelterbelt to better understand the extent of this protection and the variables which affect it. The variables investigated in this research may be classified as meteorological conditions, spray application settings, and shelterbelt properties.<p>This research investigated the movement of spray drift past a 5 m tall carragana/chokecherry shelterbelt. Spray was applied using a conventional sprayer that travelled on a path that was upwind and parallel to the shelterbelt. A tracer substance was mixed into the spray solution, and the deposition and airborne concentration of drift was measured using a variety of collectors placed at perpendicular distances up- and downwind of a shelterbelt. The mass of drift deposit on the collectors was determined using spectrofluoremetry and standard solutions.<p>When the spray swath was a distance of 3H (where H is the height of the shelterbelt) upwind of the shelterbelt, it was found that the ground deposition of drift at a distance of 0.5H downwind of the shelterbelt was reduced by approximately 74%, compared to the drift deposit at 0.5H upwind. The reduction over the same downwind distances was 29% in the open field setting. The airborne drift cloud was attenuated by the shelterbelt and the airborne concentration of drift exiting the shelterbelt was reduced by approximately 85% of the entering drift. The airborne drift concentration profile indicated that there was a greater proportion of drift travelling over the top of the shelterbelt rather than passing through the shelterbelt, with the peak concentration occurring at approximately 1.2H.<p>Qualitative and multiple linear regression analyses were used to determine the significance of a number of meteorological and controlled variables on the deposition of drift. It was found that the mass of drift deposited downwind of the shelterbelt increased with a higher wind speed, higher temperature, and lower relative humidity. For the range of meteorological conditions sampled, the effect of wind direction and atmospheric stability were found to be insignificant. Finer spray qualities and higher shelterbelt optical porosity produced greater airborne drift and deposition downwind of the shelterbelt. With increasing upwind sprayer distance, the mass of drift deposited within the shelterbelt decreased.
3

The Economics of Beneficial Management Practices Adoption on Representative Alberta Crop Farms

Trautman, Dawn E Unknown Date
No description available.
4

From cultural to supporting ecosystem services, the value of shelterbelts to prairie agriculture, Canada

Badin-Bellet, Louise 27 January 2014 (has links)
Shelterbelts were established in the Canadian Prairies as a means to protect soil from wind erosion. Knowledge gaps remain about shelterbelts' ecosystem services to the agro-landscape, hence hiding farmers' trade-offs in a changing agriculture. This research first investigated shelterbelts' effect on soil biological activity and fertility. Soil samples were collected in September 2012 from sheltered and non-sheltered fields in the Rural Municipality of Stanley, Manitoba. Results showed that shelterbelts promote higher soil biological activity, potentially correlated to the enhanced organic matter and micro-climate adjacent to shelterbelts. A survey was then conducted to explore shelterbelts' cultural services to the local community. Results indicated that while shelterbelts were perceived to significantly benefit community well-being, they were mainly recognised for agricultural functions. We conclude that shelterbelts are a significant element of both supporting and cultural ecosystem services, contributing to the prairie agro-system resilience. Further research and quantification of shelterbelts' socio-ecological services is recommended.

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