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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

Altering hydrologic regime to revgetate crusted soils on semiarid rangeland

Wentz, Amy Leigh 15 November 2004 (has links)
Dysfunctional rangelands lose nutrients and material faster than they capture or create them. The objective of this study was to determine the effectiveness of contour furrows, drill seeding, and aeration treatments in capturing overland flow, concentrating resources, and establishing perennial bunch grasses to convert dysfunctional semiarid rangeland to a functional rangeland. The site, located on the Edwards Plateau in west Texas, USA, had bare, structurally crusted soils with sparse short-grasses (Scleropogon brevifolius). The site had a low infiltration rate contributing to excess overland flow and loss of nutrients, organic matter, and soil. Contour furrows were installed with varying intra-furrow distances (0.6 to 61 m) and then broadcast seeded to determine if furrow spacing would produce a vegetative response. Portions of the intra-furrow areas were aerated and drill seeded. All seed mixes contained warm season, perennial bunch grasses (Bouteloua curtipendula, Leptochloa dubia, and Setaria leucopila). Soil beneath furrows had greater soil water content (p-value < 0.05) than intra-furrow areas. Furrow plots had greater density of seeded grasses and total vegetation (19 individuals m-2 and 191 individuals m-2, respectively) than intra-furrow plots (0 individuals m-2 and 89 individuals m-2, respectively). This study supports other findings that suggest 1.5 m to 1.8 m is optimum intra-furrow spacing. Vegetative responses to drill seeding and aeration treatments were insignificant. Observations suggest that contour furrows are effective at establishment and support of perennial vegetation by capturing and retaining water that otherwise would be lost to runoff from untreated soil.
2

Altering hydrologic regime to revgetate crusted soils on semiarid rangeland

Wentz, Amy Leigh 15 November 2004 (has links)
Dysfunctional rangelands lose nutrients and material faster than they capture or create them. The objective of this study was to determine the effectiveness of contour furrows, drill seeding, and aeration treatments in capturing overland flow, concentrating resources, and establishing perennial bunch grasses to convert dysfunctional semiarid rangeland to a functional rangeland. The site, located on the Edwards Plateau in west Texas, USA, had bare, structurally crusted soils with sparse short-grasses (Scleropogon brevifolius). The site had a low infiltration rate contributing to excess overland flow and loss of nutrients, organic matter, and soil. Contour furrows were installed with varying intra-furrow distances (0.6 to 61 m) and then broadcast seeded to determine if furrow spacing would produce a vegetative response. Portions of the intra-furrow areas were aerated and drill seeded. All seed mixes contained warm season, perennial bunch grasses (Bouteloua curtipendula, Leptochloa dubia, and Setaria leucopila). Soil beneath furrows had greater soil water content (p-value < 0.05) than intra-furrow areas. Furrow plots had greater density of seeded grasses and total vegetation (19 individuals m-2 and 191 individuals m-2, respectively) than intra-furrow plots (0 individuals m-2 and 89 individuals m-2, respectively). This study supports other findings that suggest 1.5 m to 1.8 m is optimum intra-furrow spacing. Vegetative responses to drill seeding and aeration treatments were insignificant. Observations suggest that contour furrows are effective at establishment and support of perennial vegetation by capturing and retaining water that otherwise would be lost to runoff from untreated soil.
3

The use of soil amendments in the revegetation of smelter-impacted soils near Flin Flon, MB/Creighton, SK

2014 June 1900 (has links)
Some areas near Flin Flon, MB and Creighton, SK are devoid of vegetation due to a variety of mining, smelting, forestry activities and forest fires that have occurred since the 1930’s. This study investigated the use of soil amendments to enhance revegetation in these areas. The study was comprised of two main components, an in situ study and a growth chamber trial. The in situ component was conducted to determine the efficacy of soil amendments that could be utilized in a revegetation program. The growth chamber trial examined if the amount of moisture present in the soil would have an influence on the success of vegetation survival and growth. The in situ study was conducted near Flin Flon, MB and Creighton, SK over two growing seasons and consisted of replicated treatments imposed at 12 sites. Tree seedlings [trembling aspen (Populus tremuloides Michx.) and jack pine (Pinus banksiana Lamb.)] and understory species [tufted hairgrass (Deschampsia cespitosa L.) and American vetch (Vicia americana Muhl.)] were planted at each site. Each site also received soil amendments; bone meal and meat biochar (BMB), compost, commercial mycorrhizal inoculant (EMF) and, willow biochar (WB) in combination with dolomitic limestone and fertilizer. Each site also had a control that received an application of only dolomitic limestone and fertilizer. The growth chamber trial utilized the same plant species and soil amendments as the field trial with the exclusion of willow biochar. In general, soil amendments did not influence the survival or growth of the tree seedlings in situ or in the growth chamber trial. However, the compost amendment increased survival and growth of the tufted hairgrass significantly in the growth chamber trial and to a lesser extent in the field trial. Compost also positively influenced the pH and base saturation of the soil compared to the other amendments. The mycorrhizal inoculant increased the rate of mortality of tree species in the growth chamber trial. Moisture did not influence the survival and growth of the seedlings or understory species or the efficacy of the amendment treatments in this study.

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