Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken
Agricultural drainage ditches are links between fields, lakes and oceans, having the potential to transport e.g. sediment and nutrients. When in a good condition, drainage ditches can act as sinks for e.g. phosphorus and sediments and prevent eutrophication downstream. The aim of this study was t...
| Main Author: | |
|---|---|
| Format: | L3 |
| Language: | Swedish Inglés |
| Published: |
SLU/Dept. of Soil and Environment
2013
|
| Subjects: |
| _version_ | 1855570886044680192 |
|---|---|
| author | Johansson, Hanna |
| author_browse | Johansson, Hanna |
| author_facet | Johansson, Hanna |
| author_sort | Johansson, Hanna |
| collection | Epsilon Archive for Student Projects |
| description | Agricultural drainage ditches are links between fields, lakes and oceans, having the potential to transport e.g. sediment and nutrients. When in a good condition, drainage ditches can act as sinks for e.g. phosphorus and sediments and prevent eutrophication downstream.
The aim of this study was to determine the condition of one agricultural drainage ditch and to come up with suggestions for appropriate measures. The aim was also to determine
which of the ditch’s properties that were possible to evaluate visually, which processes they represented as well as which properties required complementary physical analysis.
This in order to contribute to the work of developing a method for determining the status/condition of agricultural drainage ditches. Ten sections of the ditch were evaluated
visually according to the Madras method. Soil samples were also taken from the fields right next to the ditch and from the middle of the ditch bank from each section. The soil
type was also determined. Sediment samples were analysed for texture, micro aggregates, organic material and P-AL. Water samples were analysed for turbidity and different phosphorus fractions. The results from the Madras evaluation showed different conditions of the ditch’s sections where one section was in a bad condition and needed measures. The condition of this section was most likely due to erosion from surface runoff and from bank
failure. This was probably caused by unsatisfactory dimensions for today’s larger precipitation.
A clean out is recommended as well as starting to use protection zones on the fields next to the ditch section. The Madras method was efficient in determining the ditch’s ability to divert water and could probably be used by farmers. To determine whether the ditch was a source or a sink of phosphorus and sediment physical analysis were required. The results showed that some sections of the ditch may have functioned as sediment sources but that the ditch in general was a sediment sink because the sediment depth was larger upstream than downstream. Whether or not the ditch was a source or sink of phosphorus was more difficult to determine. The phosphorus concentrations in the water were not unusually large. However, in order to decide in the matter analysis of the ditch’s phosphorus
retention capacity should also be carried out. |
| format | L3 |
| id | RepoSLU5692 |
| institution | Swedish University of Agricultural Sciences |
| language | swe Inglés |
| publishDate | 2013 |
| publishDateSort | 2013 |
| publisher | SLU/Dept. of Soil and Environment |
| publisherStr | SLU/Dept. of Soil and Environment |
| record_format | eprints |
| spelling | RepoSLU56922013-06-18T12:43:06Z Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken Methods for determining the status of agricultural ditches : case study of an agricultural ditch in the parish of Munktorp Johansson, Hanna åkerdike öppna diken dikesunderhåll dikesstabilitet Madrasmetoden sedimenttransport övergödning fosfor Agricultural drainage ditches are links between fields, lakes and oceans, having the potential to transport e.g. sediment and nutrients. When in a good condition, drainage ditches can act as sinks for e.g. phosphorus and sediments and prevent eutrophication downstream. The aim of this study was to determine the condition of one agricultural drainage ditch and to come up with suggestions for appropriate measures. The aim was also to determine which of the ditch’s properties that were possible to evaluate visually, which processes they represented as well as which properties required complementary physical analysis. This in order to contribute to the work of developing a method for determining the status/condition of agricultural drainage ditches. Ten sections of the ditch were evaluated visually according to the Madras method. Soil samples were also taken from the fields right next to the ditch and from the middle of the ditch bank from each section. The soil type was also determined. Sediment samples were analysed for texture, micro aggregates, organic material and P-AL. Water samples were analysed for turbidity and different phosphorus fractions. The results from the Madras evaluation showed different conditions of the ditch’s sections where one section was in a bad condition and needed measures. The condition of this section was most likely due to erosion from surface runoff and from bank failure. This was probably caused by unsatisfactory dimensions for today’s larger precipitation. A clean out is recommended as well as starting to use protection zones on the fields next to the ditch section. The Madras method was efficient in determining the ditch’s ability to divert water and could probably be used by farmers. To determine whether the ditch was a source or a sink of phosphorus and sediment physical analysis were required. The results showed that some sections of the ditch may have functioned as sediment sources but that the ditch in general was a sediment sink because the sediment depth was larger upstream than downstream. Whether or not the ditch was a source or sink of phosphorus was more difficult to determine. The phosphorus concentrations in the water were not unusually large. However, in order to decide in the matter analysis of the ditch’s phosphorus retention capacity should also be carried out. Åkerdiken fungerar som länk mellan fält och sjöar och hav och kan transportera bl.a. näringsämnen och sediment. Beroende på dikets status kan det utföra viktiga funktioner som att vara sänka/lagringsplats för ex. fosfor som är det begränsande ämnet för övergödning i sötvatten. Syftet med den här studien var att bestämma status och ge åtgärdsförslag för ett åkerdike samt att utvärdera vilka av dikets egenskaper som är möjliga att utvärdera visuellt i fält, vilka processer de egenskaperna representerar, samt att definiera vilka egenskaper som inte kan utvärderas enbart visuellt utan behöver kompletterande undersökningar. Detta för att bidra i arbetet med att utveckla en metod för bestämning av åkerdikens status. Tio delsträckor av diket valdes ut och utvärderades visuellt enligt Madras-metoden. Dessutom togs jordprover från fältkanterna intill diket och från mitten av dikesbankerna. Från dessa bestämdes jordarten. Sedimentprover togs och analyserades för P-AL, textur, mikroaggregat och organiskt material. Vattenprover analyserades för turbiditet och koncentrationer av olika fosforformer. Resultaten visade varierande skick på dikessträckorna enligt Madrasutvärderingen. Endast en sträcka befann sig i dåligt skick och borde därmed åtgärdas. Skicket berodde troligen på erosion från ytavrinning och från dikesbanken som kan ha berott på otillräcklig dimensionering i och med ökade nederbördsmängder. Rensning av sträckan rekommenderas samt införandet av skyddszoner. Madras-metoden var effektiv för bedömning av dikets markavvattnande förmåga och skulle troligen kunna användas av lantbrukare. För att få svar på om diket var en fosfor- eller sedimentkälla eller ej, behövdes kompletterande analyser. Resultaten visade att vissa delsträckor av diket kan ha fungerat som sedimentkällor men generellt var diket troligen en sedimentsänka i och med att sedimentdjupet var större uppströms. Om diket var en fosforkälla eller ej var dock svårare att se. Fosforhalterna i vattnet var inte ovanligt höga men sedimentets fosforretentionsförmåga skulle också behöva mätas för att bättre avgöra frågan. SLU/Dept. of Soil and Environment 2013 L3 swe eng https://stud.epsilon.slu.se/5692/ |
| spellingShingle | åkerdike öppna diken dikesunderhåll dikesstabilitet Madrasmetoden sedimenttransport övergödning fosfor Johansson, Hanna Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken |
| title | Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken |
| title_full | Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken |
| title_fullStr | Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken |
| title_full_unstemmed | Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken |
| title_short | Metodik för bestämning av åkerdikens status : fallstudie av ett dike i Munktorps socken |
| title_sort | metodik för bestämning av åkerdikens status : fallstudie av ett dike i munktorps socken |
| topic | åkerdike öppna diken dikesunderhåll dikesstabilitet Madrasmetoden sedimenttransport övergödning fosfor |