• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • Tagged with
  • 3
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Impact of fertilizer placement on phosphorus in crop, soil, and run-off water in a brown Chernozem in south-central Saskatchewan.

2015 November 1900 (has links)
Fertilizer phosphorus (P) application rate and method are anticipated to have important influences on crop utilization and concentration and distribution of residual P in soil. This, in turn, can influence the amount of P removed in run-off water. The objective of this thesis work was to assess the influence of fertilizer P application method and rate on soybean (Glycine max (L.)) emergence, yield, and P uptake. Additionally, the forms and distribution of residual soil P following a season of crop growth, and the off-site export of applied P in simulated snowmelt run-off water was assessed. In a controlled environment study, soybean could tolerate up to 20 kg P2O5 ha-1 placed in the seed-row without significant reduction in emergence. Soybean was grown in a field study in 2014 in south-central Saskatchewan. Two sites were utilized within the same wheat stubble field (Downslope and Upslope) where fertilizer P was soil applied in the spring (seed-placed, deep band, and broadcast and incorporated) at 20 kg P2O5 ha-1 and broadcast at three rates (20, 40, and 80 kg P2O5 ha-1), along with a control treatment receiving no fertilizer P. At the Downslope position, in-soil application of fertilizer P resulted in a greater soybean yield and P uptake than broadcast application. After harvest, higher labile P concentrations were found in the zone of fertilizer P placement in the soil. Elevated concentrations of water soluble P were noted near the soil surface with broadcast P application compared to in-soil placement methods, attributed to immobility of P and lower plant utilization. A simulated snowmelt run-off event was conducted on intact soil slabs removed from the Upslope position treatments. Fertilizer P application method had a significant influence on P export with the greatest export occurring with broadcast application. Phosphorus XANES spectroscopy provided further evidence that, qualitatively, fertilizer P application method influenced speciation of fertilizer P reaction products in calcareous soil common to the Canadian prairies. Overall, it is concluded that in-soil placement of P fertilizer is a beneficial management practice in a prairie soil to maximize agronomic benefit while minimizing potential transport of fertilizer P off the field in snowmelt run-off water.
2

Laboratory-scale investigations of stormwater treatment in the Lake Tahoe Basin using chemical coagulants

Curtis, Jeffry G. January 2007 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2007. / "May, 2007." Includes bibliographical references. Online version available on the World Wide Web.
3

Identifiering av riskområden gällande dagvatten : En fallstudie baserat på Gustavslund / Identification of risk areas connected to stormwater : A case study based on Gustavslund

Meyer, Hanna January 2022 (has links)
Urbanisering och klimatförändringar i form av intensivare nederbörd är idag tvåproblemområden som båda påverkar hur samhället hanterar dagvatten, särskilt när dekombineras. Syftet med denna uppsats är därmed att undersöka hur dessa aspekter påverkar dagvattenhanteringen och vad som händer när det går fel vid planering och byggnation. Utöver det är målet att försöka identifiera områden som riskerar översvämmas på grund av detta. Till hjälp har en litteraturstudie gjorts samt platsbesök, intervjuer och analysering av flertalet kartor. Arbetet handlar om och utgår från Gustavslund, ett område i Vallentuna kommun. Här har det kommit fram att vid byggnation har dagvattnet inte hanterats korrekt och lett till översvämningar på äldre fastigheter. Dagvattensystemet och dess utloppspunkter är i grunden det störstaproblemet. Det beror delvis på felaktig planering från början i samband med lösningar som inte fungerat, men även dåligt ansvarstagande från kommunens sida. Vid planeringen utgicks det från att vardera fastighet skulle ta hand om vattnet själva med hjälp av lokalt omhändertagande av dagvatten (LOD), men detta har inte genomförts. Dagvattnet leds till ett fåtal fastigheter där det i dagsläget har svårt att föras vidare. Detta är på grund av klena trummor under närliggande väg som lutar fel samt ett pumpsystem och diken med dålig kapacitet. Även ledningar, både privata och gemensamma, med dålig prestanda bidrar till problematiken. Baserat påGustavslund kan ett par slutsatser dras i ett försök att identifiera liknande riskområden.Indikationer kan innebära bland annat att privata ledningar finns som inte kan hantera mängden vatten eller att stora höjdskillnader förekommer och leder till naturliga vattensamlingar ibostadsområden. Förhoppningarna med denna rapport är att snabbare hitta problemområden och åtgärda dessa innan problem med översvämningar uppstår. / Urbanization and climate change in the shape of more intense rainfall are today two problematic areas that both affect how society handles stormwater, especially when they are combined. The purpose of this essay is to examine how these two aspects contribute to stormwatermanagement and what happens when it goes poorly when planning and building. On top of that the goal is to identify areas that risk flooding because of this. To help with this a literature study has been done as well as a site visit, interviews and analysis of several maps. This study isabout and based upon Gustavslund, an area within Vallentuna municipality. It’s been known that the stormwater treatment when building here has not been done correctly which has led tofloodings at older properties. The system for run-off water and its outlet points is mainly the biggest problem. This is partly due to poor planning in combination with solutions that did not work, but also bad responsibility taking from the municipality. When planning it was assumedthat each household was to handle the run-off water on their own, but this has not been done. The water ends up on a few properties where it can barely keep going. This is because of feeble road drums turned the wrong way but also a pump system and ditches with low capacity. Also pipelines, both private and communal, with poor dimensions contribute to the problem. Based on Gustavslund, a few conclusions can be drawn to try and identify similar areas at risk.Indications can for instance involve private pipes that cannot handle the amount of water or big height differences in the terrain that leads to places where water gathers naturally in residential areas. Hopefully this report will help find these problematic areas faster and remedy thesebefore problems with flooding occur.

Page generated in 0.0681 seconds