| 1. |
|
|
| 2. |
- Djodjic, Faruk, et al.
(författare)
-
Kalibrering och validering av jordbruksläckagekoefficienter och beräkning av retention i små sjölösa områden
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- De svenska PLC-beräkningarna av näringsämnesbelastning från jordbruksmark är baserade på läckagekoefficienter som är framtagna med NLeCCS systemet med ingående modellerna SOILNDB (för kväve) och ICECREAMDB (för fosfor) samt verktyg för växtföljdsgenerering och för beräkning av läckagekoefficienter. Dessa beräkningar utförs för en upplösning motsvarande ett fält. Utifrån dessa läckage-koefficienter beräknas enligt PLC5-metodiken arealviktade läckagehalter för varje delavrinningsområde där rådande grödfördelningen (för ett specifikt år) används tillsammans med delavrinningsområdesspecifika uppgifter om dominerande jordart, tillhörighet till produktionsområde, lutning (enbart fosfor) och fosforhalt (enbart fosfor). Genom att testa läckagehaltsberäkningarna i jordbruksdominerade små, sjölösa avrinningsområden kan både läckagekoefficienter och indata till läckagehaltsberäkningarna utvärderas. Därför har vi inom ramen för detta projekt testat och utvärderat läckagekoefficienter och arealviktade läckagehalter i sju små avrinningsområden som domineras av jordbruksmark och där jordbruket är den största bidragande källan till näringsämnesförluster. Detta gjordes genom tillämpning av källfördelningsmodellering i ovan nämnda små avrinningsområden där två huvudscenarier simulerades. I det första scenariot utnyttjades samma indata som användes i respektive område vid PLC5-beräkningarna. I det andra scenariot togs alla tillgängliga lokala data fram för att försöka förbättra indata med avseende på jordartsfördelning, fosforhalter i marken, lutning, odlingsdata mm. Ytterligare två scenarier modellerades i de fall där enbart anpassning till bättre lokala indata inte kunde förklara avvikelser mellan uppmätta och modellerade värden. I dessa scenarier ändrades även läckagekoefficienterna genom att nya läckagekoefficienter togs fram antingen från NLeCCS genom bättre anpassad växtföljd, eller genom omkörning av ICECREAMDB-modellen. Både kväve och fosfor modellerades med FyrisNP-modellen och resultaten jämfördes med uppmätta halter och transporter. Modelleringsperiod var nio och ett halvt år med ett tidssteg på en vecka vilket harmoniserar med kalibreringsdata från befintliga miljöövervakningsprogram. Generellt visar resultat i detta projekt att arealviktade läckagehalter fram-räknade utifrån läckagekoefficienter kan beskriva transporter av näringsämnen på ett tillfredställande sätt, oftast dock först efter att hänsyn tagits till lokala för-hållanden. Med tanke på vald skala kan man också konstatera att vissa avvikelser är en logisk konsekvens av den valda metodiken med läckagekoefficienter som representerar ett årsmedelvärde. I vissa fall visade det sig också att rimliga förklaringar för de avvikande resultaten ibland saknas, och att en djupare förståelse av styrande processer är nödvändigt innan vi ens på ett konceptuellt sätt kan förbättra modellerna.Retentionsberäkningar ingick också i modelleringen där framförallt fosfor-retention mellan fältets kant och vattendragen är intressant eftersom hänsyn inte tagits till dessa processer vid PLC5-beräkningar. Även om en viss relation mellan fosforretention och områdens storlek framträder i modelleringar så är underlaget 7för litet för att kunna ge generella rekommendationer för de nationella beräkningarna. Eftersom rimliga resultat kunde uppnås i de flesta fall med tämligen enkla anpassningar och förbättringar av indata anser vi att den tillämpade metodiken kan vara ett sätt att validera erhållna läckagekoefficienter från fältmodellerna i ett tidigt stadium innan de används för nationella beräkningar. Därför föreslår vi att detta steg inkorporeras i kommande PLC-beräkningar som en extra utvärdering och justering av framtagna läckagekoefficienter innan de används för de nationella beräkningarna
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Fölster, Jens, et al.
(författare)
-
Åtgärder ger effekt
- 2012
-
Ingår i: Havet 2012. - 9789198064612 ; , s. 33-34
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 6. |
- Kyllmar, Katarina
(författare)
-
Climate change and the potential effects on runoff and nitrogen losses in the Nordic–Baltic region
- 2014
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 198, s. 114-126
-
Tidskriftsartikel (refereegranskat)abstract
- Climatic changes will influence the possibilities for agricultural production (e.g. longer growing season), agricultural management practices (e.g. changes in tillage, fertilization, increased use of fungicides) and runoff conditions, and thereby the losses of nutrients from agricultural fields to the environment. Nitrogen (N) is of particular interest in the Baltic Sea region because of its adverse effects on water quality. This paper gives an overview of the expected climatic changes in the Nordic-Baltic region, and the possible effects of these changes on runoff and N losses. Downscaled climate scenarios are used as a basis for evaluating the potential effects of climate change on hydrology, runoff and N losses. Examples from selected catchments in Nordic-Baltic water quality monitoring programmes, including data from extreme events, are presented and used for an assessment of the required adaptations. The analysis shows that there is a strong relationship between annual precipitation and runoff, and between runoff and N loss. The seasonality of precipitation, runoff and N loss indicate high losses outside the growing season. With climate change, increased precipitation is expected to occur mainly outside the growing season - in September-March - and result in increased runoff and thereby increased N losses. Existing data show that extreme events of precipitation have occurred in all seasons during the monitoring period, and have caused high runoff and high losses of N. With the expected increases in N losses, there is an urgent need for efficient measures to reduce N losses in order to fulfil the requirements of e.g. the EU Water Framework Directive (EU-WFD) and the Nitrates Directive and reduction of greenhouse gas emissions (GHG) from agriculture.
|
|
| 7. |
- Kyllmar, Katarina
(författare)
-
Hydrological pathways and nitrogen runoff in agricultural dominated catchments in Nordic and Baltic countries
- 2014
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 195, s. 211-219
-
Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) transport and retention in streams are largely determined by hydrological characteristics (e.g. water runoff, baseflow index (BFI) and flashiness index (FI)) in the catchment. It is important to know the impact of catchment characteristics such as land use, subsurface drainage intensity, elevation difference and catchment size on the hydrological properties and N loss. This paper presents a comparison of the magnitude and variation of the baseflow and flashiness in streams in relation to the selected geographical and drainage characteristics for thirty studied agriculture dominated catchments in the Nordic and Baltic countries and the effects it can have on N loss. The analysis included measured data from the total discharge and nitrogen loss at the catchment outlets for the period from the beginning of 1993 to 2011, although there is variation in the length of periods among catchments and countries. The study revealed that the rate of subsurface drainage systems and drainage intensity (given as lateral tile drainage spacing) were statistically significant explanatory variables in explaining differences in hydrological characteristics between catchments. There is a considerable increase in the El, almost by a factor of three, when using hourly discharge values instead of average daily values, indicating that large diurnal variation in discharge can occur, especially at higher FI values. The analysis also showed that there is a negative relation between FI and the BFI, i.e. a high BFI corresponding to a low FI and vice versa. In general, there seems to be a positive relationship between long-term average runoff and N loss, with the highest runoff and N loss occurring in the Norwegian catchments. However, flow path can have a significant influence on the N loss. (C) 2014 Elsevier B.V. All rights reserved.
|
|
| 8. |
- Kyllmar, Katarina
(författare)
-
Long-term monitoring of nutrient losses from agricultural catchments in the Nordic-Baltic region - A discussion of methods, uncertainties
- 2014
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 198, s. 4-12
-
Tidskriftsartikel (refereegranskat)abstract
- Monitoring of nutrient losses to surface waters at the small agricultural catchment scale has been carried out in seven Nordic and Baltic countries for the past two decades, with the aim of obtaining information on agricultural activities and their impact on surrounding waters. The monitoring methods have been harmonised and in almost all 35 catchments currently being monitored, water samples are taken flow-proportionally, water discharge is measured continuously and information on crops grown and crop management is collected yearly. Here, we evaluate and discuss uncertainties in data and their consequences for fulfilling the aim of the monitoring systems. We also suggest methods and priorities for future monitoring. Although the catchments altogether cover major variations in climate, soil texture and farm type, there is a bias towards more intensive agricultural production compared with the surrounding agricultural regions. For applicability of the results to larger agricultural areas, the representativity of the selected catchments should be stated. The determination of nutrient loads is affected by uncertainties in water discharge measurements, water sampling and chemical analyses, but these uncertainties may decrease over time due to improvements in the methods used. This would improve the possibility to detect trends in the naturally large variation in nutrient loads. For wider applications, the level of nutrient loads at the catchment stream outlet must be related to catchment characteristics such as proportion of agricultural land and contribution from other land uses and point sources. These sources are often estimated based on limited information, but should be included regularly in monitoring schemes. Also data on agricultural activities are related to uncertainties such as coverage of crop management information and nutrient content in manure and harvested products. When data are missing, standard values are used, further contributing to uncertainties. However, intensive monitoring increases awareness of sources of uncertainty in data, and hence the possibility to reduce these uncertainties. Therefore, the intensive monitoring approach should be maintained and rather extended, for example by using sensors for high resolution water quality measurements so that the variations can be identified and related to catchment activities and to processes in streams and groundwater. To further understand these processes and crop management systems, modelling should be closely related to monitoring. With harmonised monitoring programmes where differences in methods are known, focus can be put on the evaluation of data so that further knowledge on the impact of agriculture on the environment can be obtained.
|
|
| 9. |
- Kyllmar, Katarina
(författare)
-
Mitigating diffuse nitrogen losses in the Nordic-Baltic countries
- 2014
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 195, s. 53-60
-
Tidskriftsartikel (refereegranskat)abstract
- Concerns over deteriorating water quality in both freshwater and marine waters have initiated efforts to control diffuse nitrogen (N) losses in all Nordic-Baltic countries. The national strategies for combating diffuse nitrogen losses including selection of mitigation measures, areal extent of measures and incentives for farmers to use the measures differ between the Nordic-Baltic countries. Effects of legislation and other incentives to change agricultural practices and hence to reduce N losses from agriculture are first observed by monitoring close to the source of these losses. Consequently, all Nordic-Baltic countries have set up monitoring programmes including small agriculturally dominated catchments where inputs, outputs and loss of N are followed closely at plot, field and/or catchment scale. We explore the connection between political decisions and regulations, provide an overview of measures and incentives used in the Nordic-Baltic countries, and assess the effect of the measures based on data from national monitoring programmes. (C) 2014 Elsevier B.V. All rights reserved.
|
|
| 10. |
- Kyllmar, Katarina
(författare)
-
Nitrogen application, balances and their effect on water quality in small catchments in the Nordic-Baltic countries
- 2014
-
Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 198, s. 104-113
-
Tidskriftsartikel (refereegranskat)abstract
- Various strategies to reduce loss of nitrogen (N) from agricultural land have been implemented in the Nordic-Baltic countries during the last two decades to combat nutrient pollution of surface waters. The mitigation methods have led to a significant reduction in the consumption of N fertilizers in some of the Nordic-Baltic countries. The objective of this study was to investigate trends in N application and N balance and their effect on N concentrations in runoff from agricultural areas. Nitrogen balances consisted of N input in fertilizer, manure, deposition and fixation minus N output in yield. The study was based on monitoring in small agricultural streams in the Nordic-Baltic region over the last two decades with corresponding information on average N application (28 catchments) and N balance (27 catchments) for a varying periods. Long-term time series (14-22 years) on annual N application was available for 17 catchments and for 14 of these catchments, annual information on N balances were also available for the long-term time series. Nitrogen balances were available for 23 catchments for 2007-2011 and our results showed that on average for this period the N balance varied from -12Nha-1yr-1 in Volbu to 132kgNha-1yr-1 in Time, both located in Norway. For long-term time series, we found that the N application rates decreased significantly in six catchments, but increased in five catchments. Furthermore, the N balances decreased in four catchments but increased in two catchments. Hence the results describe the differences in agricultural development between countries, caused by e.g. changes in livestock production (Norway), strict regulations of fertilizer application (Denmark) and increased intensity in production (Latvia). The results showed that for 10 of the 14 catchments with long-term time series, there was no significant relationship between annual N balances and N concentrations. The effect of changes in N balances on N concentrations were significant for four of the 14 long-term time series which showed positive relationships (p=0.0002, 0.0013, 0.0087, 0.0893) between annual N balances for the agricultural area in the catchments and N concentrations in the streams. The significant relationship between N balances and N concentrations were detected where long-term trends in N balances were identified and where a large change in N balances from a very high N surplus occurred.
|
|
