| 1. |
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| 2. |
- Aronsson, Helena, et al.
(författare)
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Fosforbeting att bita i
- 2011
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Ingår i: Återvinna fosfor - hur bråttom är det?. - 9789154060641 ; , s. 135-149
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Bokkapitel (populärvet., debatt m.m.)
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| 3. |
- Aronsson, Helena, et al.
(författare)
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Leaching of N, P and glyphosate from two soils after herbicide treatment and incorporation of a ryegrass catch crop
- 2011
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Ingår i: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 27, s. 54-68
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Tidskriftsartikel (refereegranskat)abstract
- During 2005-2007, studies were carried out in two field experiments in southwest Sweden with separately tile-drained plots on a sandy soil (three replicates) and on a clay soil (two replicates). The overall aim was to determine the effects of different cropping systems with catch crops on losses of N, P and glyphosate. Different times of glyphosate treatment of undersown ryegrass catch crops were examined in combination with soil tillage in November or spring. Drainage water was sampled continuously in proportion to water flow and analysed for N, P and glyphosate. Catch crops were sampled in late autumn and spring and soil was analysed for mineral N content. The yields of following cereal crops were determined. The importance of keeping the catch crop growing as long as possible in the autumn is demonstrated to decrease the risk of N leaching. During a year with high drainage on the sandy soil, annual N leaching was 26 kg/ha higher for plots with a catch crop killed with glyphosate in late September than for plots with a catch crop, while the difference was very small during 1 yr with less drainage. Having the catch crop in place during October was the most important factor, whereas the time of incorporation of a dead catch crop did not influence N leaching from either of the two soils. However, incorporation of a growing catch crop in spring resulted in decreased crop yields, especially on the clay soil. Soil type affected glyphosate leaching to a larger extent than the experimental treatments. Glyphosate was not leached from the sand at all, while it was found at average concentrations of 0.25 mu g/L in drainage water from the clay soil on all sampling occasions. Phosphorus leaching also varied (on average 0.2 and 0.5 kg/ha/yr from the sand and clay, respectively), but was not significantly affected by the different catch crop treatments.
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| 4. |
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| 5. |
- Aronsson, Helena, et al.
(författare)
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The ability of cover crops to reduce nitrogen and phosphorus losses from arable land in southern Scandinavia and Finland
- 2016
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Ingår i: Journal of Soil and Water Conservation. - : Soil and Water Conservation Society. - 0022-4561 .- 1941-3300. ; 71, s. 41-55
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Tidskriftsartikel (refereegranskat)abstract
- This review summarizes current knowledge from the literature and experimental studies on the role of cover crops (CCs) in reducing nitrogen (N) leaching and phosphorus (P) losses to waters under the marine and humid continental climate conditions of southern Scandinavia and Finland. Field leaching studies from 11 sites indicate that undersown ryegrass (Lolium spp.) CCs are robust, with average N uptake in aboveground CC biomass of 7 to 38 kg N ha(-1) (6.2 to 34 lb N ac(-1)). Use of CCs sown at harvest (e.g., crucifers) is restricted to southern Scandinavia for climate reasons. The mean relative reduction in N leaching reported for all CCs investigated was 43%, but it ranged between 62% increase instead of a reduction after a red clover (Trifolium pratense) CC on a clay soil to a reduction of 85% to 89% with a perennial ryegrass CC on sandy soils in Denmark (36 to 51 kg ha(-1) [32 to 46 lb ac(-1)]). The data indicate that CCs do not substantially reduce total P losses by runoff and leaching. The effects of CCs on total P leaching varied between a relative increase of 86% and a decrease of 43%. Climate conditions involving freezing-thawing during winter increased the risk of losses of dissolved P from CC biomass. CCs have been implemented to varying degrees into agri-environmental programs. They are mandatory in Denmark and subsidized in Norway, Sweden, and Finland. CCs are grown on 8% of arable land in Denmark, 5% in Sweden, 1% in Finland, and 0.5% in Norway, but CC area is now increasing dramatically in Finland due to a new subsidy program. In all countries there is a need, and potential, for increased use of CCs, but there are several constraints, particularly reduced interest among farmers. There is a clear need to identify CC systems and develop implementation strategies for appropriate distribution of CCs on different soils and regions with respect to required reductions in N leaching and P losses. For this, more knowledge is required, especially about the effect of CCs on P losses (e.g., the effect of species with different partitioning between shoot and root biomass and the effects of CC systems with harvesting of biomass). There is also a need to devise balanced solutions for maintaining and increasing the frequency of CCs in crop rotations to exploit the possible benefits of CCs in reducing nutrient losses.
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| 6. |
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| 7. |
- Bergström, Lars, et al.
(författare)
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Turnover and Losses of Phosphorus in Swedish Agricultural Soils: Long-Term Changes, Leaching Trends, and Mitigation Measures
- 2015
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Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425 .- 1537-2537. ; 44, s. 512-523
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Tidskriftsartikel (refereegranskat)abstract
- Transport of phosphorus (P) from agricultural fields to water bodies deteriorates water quality and causes eutrophication. To reduce P losses and optimize P use efficiency by crops, better knowledge is needed of P turnover in soil and the efficiency of best management practices (BMPs). In this review, we examined these issues using results from 10 Swedish long-term soil fertility trials and various studies on subsurface losses of P. The fertility trials are more than 50 years old and consist of two cropping systems with farmyard manure and mineral fertilizer. One major finding was that replacement of P removed by crops with fertilizer P was not sufficient to maintain soil P concentrations, determined with acid ammonium lactate extraction. The BMPs for reducing P leaching losses reviewed here included catch crops, constructed wetlands, structure liming of clay soils, and various manure application strategies. None of the eight catch crops tested reduced P leaching significantly, whereas total P loads were reduced by 36% by wetland installation, by 39 to 55% by structure liming (tested at two sites), and by 50% by incorporation of pig slurry into a clay soil instead of surface application. Trend analysis of P monitoring data since the 1980s for a number of small Swedish catchments in which various BMPs have been implemented showed no clear pattern, and both upward and downward trends were observed. However, other factors, such as weather conditions and soil type, have profound effects on P losses, which can mask the effects of BMPs.
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| 8. |
- Bieroza, Magdalena, et al.
(författare)
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Hydrologic Extremes and Legacy Sources Can Override Efforts to Mitigate Nutrient and Sediment Losses at the Catchment Scale
- 2019
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Ingår i: Journal of Environmental Quality. - : AMER SOC AGRONOMY. - 0047-2425 .- 1537-2537. ; 48:5, s. 1314-1324
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Tidskriftsartikel (refereegranskat)abstract
- Combating eutrophication requires changes in land and water management in agricultural catchments and implementation of mitigation measures to reduce phosphorus (P), nitrogen (N) and suspended sediment (SS) losses. To date, such mitigation measures have been built in many agricultural catchments, but there is a lack of studies evaluating their effectiveness. Here we evaluated the effectiveness of mitigation measures in a clay soildominated headwater catchment by combining the evaluation of long-term and high-frequency data with punctual measurements upstream and downstream of three mitigation measures: limefilter drains, a two-stage ditch, and a sedimentation pond. Long-term hydrochemical data at the catchment outlet showed a significant decrease in P (-15%) and SS (-28%) and an increase in nitrate nitrogen (NO3-N, + 13%) concentrations. Highfrequency (hourly) measurements with a wet-chemistry analyzer (total and reactive P) and optical sensor (NO3-N and SS) showed that the catchment is an abundant source of nutrients and sediments and that their transport is exacerbated by prolonged drought and resuspension of stream sediments during storm events. Lime-filter drains showed a decrease in SS by 76% and total P by 80% and an increase in NO3-N by 45% compared with traditional drains, potentially indicating pollution swapping. The effectiveness of two-stage ditch and sedimentation pond was less evident and depended on the prevalent hydrometeorological conditions that drove the resuspension of bed sediments and associated sediment-bound P transport. These results suggest that increased frequency of prolonged drought due to changing weather patterns and resuspension of SS and sediment-bound P during storm events can override the generally positive effect of mitigation measures.
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| 9. |
- Björck, Lennart, et al.
(författare)
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Tveksam vinst med ekolantbruk
- 2009
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Ingår i: Svenska dagbladet. - 1101-2412. ; -
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 10. |
- Blomberg, Maria, et al.
(författare)
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Innebär tillförsel av biogödsel runt Bornsjön ökad risk för fosforläckage? : en lysimeterstudie med tillförsel av rötade matrester och mineralgödsel
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Att använda biogödsel såsom rötat matavfall som ersättning till mineralgödsel diskuteras för att recirkulera fosfor inom jordbruket. I denna pilotstudie undersöktes om fosforläckaget efter tillförsel av avvattnat rötat matavfall skiljde sig jämfört med tillförsel av mineralgödsel (monoammoniumfosfat) och utan gödsling (kontroll). Biogödseln bestod av rötat matavfall med en fosforhalt av 12% beräknad per torrvikt. De tre försöksleden utsattes för fem bevattningscykler som genererade avrinning. Gödselgivan motsvarade den högsta tillåtna och regnintensitet valdes så att det motsvarar ett värsta tänkbara scenario. Denna pilotstudie visar inte på någon förhöjd risk att sprida avvattnad biogödsel på en lerjord av den typ som användes. Effekter på näringsläckage från rötat matavfall behöver dock undersökas vidare i fältförsök.
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| 11. |
- Braun, Sabina, et al.
(författare)
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Assessing the ability of soil tests to estimate labile phosphorus in agricultural soils : Evidence from isotopic exchange
- 2019
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Ingår i: Geoderma. - : Elsevier. - 0016-7061 .- 1872-6259. ; 337, s. 350-358
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Tidskriftsartikel (refereegranskat)abstract
- Efficient phosphorus (P) fertilization strategies are essential for intensive crop production with minimal negative environmental impacts. A key factor in sustainable P use is assessment of the plant available soil P pool using soil P tests. This study determined isotopically exchangeable P after six days of reaction with 33PO4 (P-E (6 d)) to determine how accurately two commonly used P tests, Olsen and AL (acid ammonium acetate lactate) can quantify the amount of labile P. Soil samples were taken from both highly P-amended and unamended plots at six sites within the Swedish long-term soil fertility experiments. According to P K-edge XANES spectroscopy, the P speciation was dominated by Al-bound P and organic P, with additional contributions from Fe-bound P and Ca phosphates in most soils. The results showed that the AL test overestimated P-E (6 d) by a factor of 1.70 on average. In contrast, the Olsen test underestimated P-E (6 d), with the mean ratios of P-Olsen to P-E (6 d) being 0.52 for high-P and 0.19 for low-P soils. The 33P/31P ratio in the Olsen extract of a 33PO4 spiked soil was closer to that of a 0.005 mol L−1 CaCl2 soil extract than the corresponding ratio in the AL extract, suggesting that AL extraction solubilized more non-labile P. In conclusion, the AL and Olsen methods are not suitable for direct quantification of the isotopically exchangeable soil P pool after 6 days of equilibration. However, based on the results, Olsen may be superior to AL for classification of soil P status, due to its even performance for calcareous and non-calcareous soils and lower extraction of non-labile P.
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| 12. |
- Bölscher, Tobias, et al.
(författare)
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Changes in pore networks and readily dispersible soil following structure liming of clay soils
- 2021
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Ingår i: Geoderma. - : Elsevier BV. - 0016-7061 .- 1872-6259. ; 390
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Tidskriftsartikel (refereegranskat)abstract
- Structure liming aims to improve soil structure (i.e., the spatial arrangement of particles and pores) and its stability against external and internal forces. Effects of lime application on soil structure have received considerable interest, but only a few studies have investigated effects on macro- and mesopore networks. We used X-ray computed tomography to image macropore networks (ø ≥ 0.3 mm) in soil columns and mesopores (ø ≥ 0.01 mm) in soil aggregates from three field sites with (silty) clay soils after the application of structure lime (3.1 t ha−1 or 5 t ha−1 of CaO equivalent). Segmented X-ray images were used to quantify soil porosity and pore size distributions as well as to analyse pore architecture and connectivity metrics. In addition, we investigated the amount of readily dispersible soil particles. Our results demonstrate that structure liming affected both, macropore networks and amounts of readily dispersible soil to different degrees, depending on the field site. Significant changes in macropore networks and amounts of readily dispersible soil after lime application were found for one of the three field sites, while only some indications for similar changes were observed at the other two sites. Overall, structure liming tended to decrease soil macroporosity and shift pore size distribution from larger (ε>1.0 mm) and medium sized macropores (ε0.3–1.0 mm) towards smaller macropores (ε0.1–0.3 mm). Furthermore, liming tended to decrease the critical and average pore diameters, while increasing the surface fractal dimension and specific surface area of macropore network. Structure liming also reduced the amounts of readily dispersible soil particles. We did not find any changes in mesopore network properties within soil aggregates or biopore networks in columns and aggregates. The effects of lime on macropore networks remain elusive, but may be caused by the formation of hydrate phases and carbonates which occupy pore space.
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| 13. |
- Carlsson, Carina, et al.
(författare)
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Typområden på jordbruksmark : Växtnäringsförluster i små jordbruksdominerade avrinningsområden 2001/2002
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I det regionala miljöövervakningsprogrammet ”Typområden på jordbruksmark” undersöks för närvarande 28 stycken små jordbruksdominerade avrinningsområden. Syftet är att följa odlingens inverkan på vattenkvalitén i avrinnande vatten till bäck eller å. I denna sammanställning redovisas resultat från det agrohydrologiska året 2001/2002, bl a flödesvägda halter, transporter,klimat och hur odlingsförutsättningarna har varit.Åkermarkens nettoarealförlust (utlakning till rotzonen minus retentionsförluster och förluster till djupare grundvatten) har inte skattats i årets rapport. Detta innebär att det är den totala transporten som redovisas och i den ingår inte bara läckage från åkermark utan även t ex förluster från punktkällor.Hösten 2001 och vintern 2001/2002 var mild och på många håll nederbördsrik. Den rikliga nederbörden ledde till stora oskördade arealer hösten 2001 och även till att den höstsådda arealen blev liten. Trots riklig nederbörd blev avrinningen för områdena i Svealand måttlig. Halterna av kväve för typområdena i Svealand var däremot medel till över medel för perioden medan halterna av fosfor var i nivå med tidigare år. Den högre avrinningen som förekom i områdena i Skåne, Blekinge och Hallands län gav däremot inte upphov till några höga halter i jämförelse med långtidsmedel, varken av kväve eller fosfor. Däremot gjorde en hög avrinning att transporterna blev relativt höga och medel för produktionsområdena Götalands slätt- och mellanbygder översteg långtidsmedel betydligt för både kväve och fosfor.I januari 2002 förändrades programmet typområden på jordbruksmark i och med att åtta områden överfördes till ett nationellt, så kallat intensivprogram. Detta innebär bl a att vattenprover tas med tätare intervall i områdena och både i ytoch grundvatten. Som en kvalitetskontroll av analyser gjordes en jämförelse med laboratoriet på avdelningen för vattenvårdslära och två andra laboratorier som användes för två områden. Resultaten pekar på en del skillnader mellan laboratorierna t ex i metoden för analys av suspenderat material. För de laboratorier som analyserar recipientvatten från jordbruksmark skulle analys av suspenderat material, förfiltrering för fosfatanalys och bestämningen av fosfor behöva interkalibreras.
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| 14. |
- Drangert, Jan-Olof, 1944-, et al.
(författare)
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Generating Applicable Environmental Knowledge among Farmers : Experiences from Two Regions in Poland
- 2017
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Ingår i: Agroecology and Sustainable Food Systems. - : Taylor & Francis. - 2168-3565 .- 2168-3573. ; 41:6, s. 671-690
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Tidskriftsartikel (refereegranskat)abstract
- Raising environmental awareness among farmers is the key to successfully reaching environmental goals. The present study assessed the knowledge development process and the raising of environmental awareness among 30 farmers from Poland exposed to four approaches aimed to reduce phosphorus (P) and nitrogen (N) losses to water. The farmers were interviewed with open-ended questions on-farm both before and after the project intervention. As hoped, the farmers attempted to adjust their farm practices to the European Union regulations, which are in some cases supported by subsidies. As a complement, the project offered tools for system-thinking based on farm data and support from agricultural advisors: a) a survey of plant-available P, potassium (K), magnesium (Mg), and soil pH, resulting in soil maps; b) assessment of nitrogen leaching risks from individual fields; c) compilation of a farm-gate balance. Farmers were positive to soil surveys and maps, but had limited understanding of the nutrient balance concept and calculations. They generally relied on their own experiences regarding fertilization rather than on calculated farm nutrient balances and leaching risks. Farmers’ understanding and willingness to adopt new approaches to improve nutrient efficiency and reduce negative environmental impacts are discussed.
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| 15. |
- Ejhed, Helene, et al.
(författare)
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Uppskattning av utsläpp för Cd, Hg, Cu ochZn på TRK-områden : Slutrapport januari 2005
- 2005
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport sammanställer lokala bruttoutsläpp av diffusa källor , punktkällor samt totalt utsläpp av metallerna kadmium, koppar, kvicksilver och zink geografiskt fördelat till rapporteringsområden för att ge underlag till rapportering enligt ramdirektivet för vatten. Ingen beräkning av avskiljning av metaller till mark eller sediment under transporten genom vattensystemet har genomförts.Utsläpp av diffusa källor har beräknats baserat på inom projektet nya framtagna typhalter och samband för utlakning av metaller för olika markanvändning samt sammanställningar av kända typhalter för utlakning av typhalter där de bedömts vara trovärdiga. De nya typhalterna baseras på uppmätta halter från miljöövervakningsprogram för sjöar och vattendrag samt typområden för jordbruksmark. Deposition av metallerna på öppen sjöyta har tagits fram baserat på uppmätta depositionsvärden kopplat till nederbörd för området samt för metallerna kadmium, koppar och zink baserat på ett omfattande nätverk av uppmätta halter i husmossa och väggmossa. Typhalterna har multiplicerats markanvändning som till stor del tagits fram inom TRK-projektet förutom vägmark som tagits fram för det statliga vägnätet inom detta projekt. Typhalterna har också multiplicerats med avrinningen för området som togs fram inom TRK-projektet som ett långtidsmedel för perioden 1985-2000. Stora punktutsläpp har framför allt inhämtats från Länsstyrelsens databas EMIR med efterföljande omfattande kvalitetssäkring av data. Data har inhämtats för år 2003 eller senast registrerat data, nedlagd verksamhet exkluderad utom avseende deponier och avfallsupplag. Utöver denna databas har data inhämtats från enskilda Statistiska meddelanden avseende utsläpp från reningsverk och miljörapporter och uppgifter från Länsstyrelser och Naturvårdsverks rapporter avseende gruvverksamhet samt SMED rapport avseende avfallsanläggningar. Små punktkällor har ansatts schabloner för utsläpp baserat på resultat i enskilda referenser och SMED rapporter och avseende små reningsverk baserat på medelvärde för reningsgrad och föroreningsmängd redovisat för stora reningsverk.Resultaten redovisas i tabeller summerat per vattendistrikt och i kartbilder över utsläppen per rapporteringsområde och havsområde. Kartorna läggs till rapporten i separata filer med numrering enligt rapportens avsnitt kartbilder. Kartorna presenterar klassade data enligt percentil indelning av utsläpp i kg i 25:e, 50:e, 75:e och 90:e percentilen för att visa fördelningen av utsläppen så tydligt som möjligt samt kartor över omräknat utsläpp vid källan med hjälp av avrinning och områdets areal till mg/l med klassning enligt bedömningsgrunder för miljökvalitet, sjöar och vattendrag för att visa utsläppen i förhållande till gränser för biologisk effekt. Resultaten presenteras även för tillförseln till havsområden klassade enligt 25:e, 50:e, 75:e samt 95:e percentilen av diffusa utsläpp och totalt utsläpp i enheten g/ha för att skillnader i tillrinningsområdets areal inte skulle dominera resultatet. Tillförseln av punktkällor till havsområdena presenteras totalt summerat i kg eftersom dessa källor inte är relaterade till arealen. Jämförelser mellan beräknat resultat och beräknade transporter baserat på uppmätta halter i flodmynningarna visar att beräkningarna är av rätt storleksordning. Vissa områden har större transport baserat på uppmätta data än beräknat resultat och kan bero på brister i de ingående utsläppen eller avsaknad av utsläppskällor som till exempel återcirkulation av metaller från sediment.Osäkerheter i markläckagens storlek vilka står för en stor del av utsläppen kan också vara en orsak till skillnad i resultat och transporterad mängd i flodmynningarna. Resultaten för jordbruksmarkens utlakning av kadmium jämfördes dessutom med en beräkning av kadmiumbalansen baserat på tillförsel i form av gödsel, kalkning, utsäde, deposition samt slam och bortförsel i form av upptag i gröda till jordbruksmarken.Skillnader mellan resultat i denna rapport och tidigare totala sammanställningar av utsläpp av metaller till vatten beskrivs översiktligt i avsnittet diskussion. Brister i indata redovisas delvis i delrapporter avseende typhalter för de diffusa markläckagen i appendix till rapporten och delvis i avsnittet bristanalys. Estimerat bortfall av utsläpp för olika typer av större punktkällor på grund av saknade data har beräknats och visar att stora enskilda utsläpp troligen saknas i rapportens resultat.
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| 16. |
- Eriksson, Ann Kristin, et al.
(författare)
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Evolution of phosphorus speciation with depth in an agricultural soil profile
- 2016
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Ingår i: Geoderma. - : Elsevier. - 0016-7061 .- 1872-6259. ; 280, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- With time, different soil-forming processes such as weathering, plant growth, accumulation of organic matter, and cultivation are likely to affect phosphorus (P) speciation. In this study, the depth distribution of P species was investigated for an agricultural clay soil, Lanna, Sweden. Small amounts of apatite-P was demonstrated in the topsoil whereas the speciation of Pat 70-100 cm depth consisted of approximately 86% apatite according to P K-edge XANES (X-ray absorption near-edge structure) spectroscopy. Because there were only minor differences in bulk mineralogy and texture, these variations in P speciation were interpreted as the result of apatite weathering of the topsoil. Speciation modeling on soil extracts supported this idea: hydroxyapatite was not thermodynamically stable in the top 50 cm of the soil. Apatite was enriched in the bulk soil relative to the clay fraction, as expected during apatite dissolution. Combined results from batch experiments, XANES spectroscopy and X-ray diffraction suggested chemical transformations of the topsoil as a result from accumulation of organic matter and airing from tillage followed by enhanced weathering of apatite, amphiboles, clay minerals, and iron oxides. This caused the formation of poorly crystalline secondary iron and aluminum (hydr)oxides in the topsoil, which retained part of the released P from apatite. Other P was incorporated into organic forms. Furthermore, the results also showed that short-term acidification below the current pH value (below 5.5 in the topsoil and 7.2 in the deeper subsoil) caused significant solubilization of P. This is attributed to two different mechanisms: the instability of Al-containing sorbents (e.g. Al hydroxides) at low pH (in the topsoil), and the acid-mediated dissolution of apatite (the subsoil).
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| 17. |
- Eriksson, Ann Kristin, et al.
(författare)
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Phosphorus in Agricultural soils around the Baltic Sea : comparison of laboratory methods as indices for phosphorus leaching to waters
- 2013
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Ingår i: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 29, s. 5-14
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigated the phosphorus (P) content of Baltic soils. In the first set of analyses, 99 soil samples from the Baltic states and Sweden (soil set 1, representing seven different catchments or experimental plots) were analysed for soil P using four extraction methods: ammonium lactate (P-AL) P double lactate (P DL) Mehlich 3 (PM3) and carbonate (P Olsen) (r=0.85-0.97) In abolute values,results from PM3, PDL and P Olsen gave means of 71, 61 and 20%, respectively, of the values from the PAL extraction method. Significantly different relationships were found between P soil concentrations and pH of the extract. In addition, soil pH and organic matter content were found to be of importance. Secondly, we tested 110 soil samples (soil set 2) from five different Swedish monitoring fields with clay soils where PAL clearly correlated with soil P extracted in calcium chloride (PCaCl2) (R= 0.95). Values of a single-point phosphorus sorption index (PSI) correlated with the aluminium concentration (AlAL) tests with different extraction agents - calcium chloride (PCaCL2w) water (Pw), POlsen or PAL - correlated with the mean annual flow-weighted concentration (1999–2010) of dissolved reactive P (DRP) in drainage water. Neither was there any clear relationship between DRP concentration in drainage water and these tests combined with PSI or with other sorption indices including extracted Al and iron (Fe). However, DRP was related to the clay content of the topsoil (r = 0.91, P < 0.05).
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| 18. |
- Geranmayeh, Pia, et al.
(författare)
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Particle deposition, resuspension and phosphorus accumulation in small constructed wetlands
- 2018
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Ingår i: Ambio. - : SPRINGER. - 0044-7447 .- 1654-7209. ; 47, s. 134-145
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Tidskriftsartikel (refereegranskat)abstract
- To improve understanding of phosphorus (P) retention processes in small constructed wetlands (CWs), we analysed variations in sediment deposition and accumulation in four CWs on clay soils in east-central Sweden. Sediment deposition (in traps) generally exceeded the total suspended solids (TSS) load suggesting that resuspension and wetland base erosion were important. This was confirmed by quantification of particle accumulation (on plates) (1-23 kg m(-2) year(-1)), which amounted to only 13-23% of trap deposition. Spatial mean P concentrations in accumulated sediment on plates (0.09-0.15%) were generally similar to temporal mean P concentrations of particles in water (0.11-0.15%). Deposition/accumulation was minor in one wetland with high hydraulic load (400 m year(-1)), suggesting that such small wetlands are not efficient as particle sinks. Economic support for CWs are given, but design and landscape position are here demonstrated to be important for effective P retention.
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| 19. |
- Geranmayeh, Pia, et al.
(författare)
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Phosphorus Retention in a Newly Constructed Wetland Receiving Agricultural Tile Drainage Water
- 2013
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Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425 .- 1537-2537. ; 42, s. 596-605
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Tidskriftsartikel (refereegranskat)abstract
- One measure used in Sweden to mitigate eutrophication of waters is the construction of small wetlands (free water surface wetland for phosphorus retention [P wetlands]) to trap particulate phosphorus (PP) transported in ditches and streams. This study evaluated P retention dynamics in a newly constructed P wetland serving a 26-ha agricultural catchment with clay soil. Flow-proportional composite water samples were collected at the wetland inlet and outlet over 2 yr (2010-2011) and analyzed for total P (TP), dissolved P (DP), particulate P (PP), and total suspended solids (TSS). Both winters had unusually long periods of snow accumulation, and additional time-proportional water samples were frequently collected during snowmelt. Inflow TP and DP concentrations varied greatly (0.02-1.09 mg L-1) during the sampling period. During snowmelt in 2010, there was a daily oscillation in P concentration and water flow in line with air temperature variations. Outflow P concentrations were generally lower than inflow concentrations, with net P losses observed only in August and December 2010. On an annual basis, the wetland acted as a net P sink, with mean specific retention of 69 kg TP, 17 kg DP, and 30 t TSS ha(-1) yr(-1), corresponding to a reduction in losses of 0.22 kg TP ha(-1) yr(-1) from the agricultural catchment. Relative retention was high (36% TP, 9% DP, and 36% TSS), indicating that small constructed wetlands (0.3% of catchment area) can substantially reduce P loads from agricultural clay soils with moderately undulating topography.
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| 20. |
- Gustafson, Arne, et al.
(författare)
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Observationsfält på åkermark : Avrinning och växtnäringsförluster för de agrohydrologiska åren 1996/97, 97/98 och 98/99 samt en långtidsöversikt
- 2001
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Samhället har såväl på ett nationellt plan som genom internationella överenskommelser uppställt klara miljömål för acceptabla inverkansnivåer på vattensystemen orsakade av bl. a. växt- och animalieproduktionen. Sektorsmål och åtgärdsprogram för reduktion av växtnäringsförluster från jordbruk har upprättats (Jordbruksverket, 2000). Genom miljöövervakning kontrolleras graden av måluppfyllelse, samtidigt som övervakningen interagerar med forskningen. Observationsfält på åkermark är en metod för att följa jordbrukets förändrade odlingsåtgärder och hur detta inverkar på kvalitén på det avrinnande vattnet från jordbruksmarken.
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| 21. |
- Hellner, Qarin, et al.
(författare)
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Effects of tillage and liming on macropore networks derived from X-ray tomography images of a silty clay soil
- 2018
-
Ingår i: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 34, s. 197-205
-
Tidskriftsartikel (refereegranskat)abstract
- Soil structure influences water infiltration, aeration and root growth and, thereby, also the conditions for sustainable crop production. Our objective was to quantify the effects of different soil management methods and land uses on the topsoil structure of a silty clay soil. We sampled 32 intact soil columns (18 cm high, 12.7 cm diameter) from an experimental silty clay field with four treatments: conventional tillage (CT), conventional tillage followed by liming (CTL), reduced tillage (RT) and unfertilized fallow (UF). The columns were analysed using 3-D X-ray tomography. The samples were taken in autumn after harvest, 7 yr after quick lime was applied to the CTL plots. Despite a relatively large number of replicates per treatment (8, 8, 8 and 6 (two UF samples were excluded), respectively), there were no significant differences between any of the investigated macropore network properties related to tilled treatments. The UF treatment, in contrast, exhibited more vertically oriented macropores, which were also better connected compared to the other treatments. This confirms previous findings that tillage may disrupt the vertical continuity of macropore clusters. The impact of liming on soil pore network properties may have been limited to pores smaller than the resolution in our X-ray images. It is also possible that the effects of lime on soil structure were limited to a few years which means that any effect would have diminished by the time of this study. These matters should be further investigated in follow-up studies to understand better the potential of lime amendments to clay soil.
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| 22. |
- Holmberg, Helena, et al.
(författare)
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Bekämpningsmedel i vatten från typområden, åar och i nederbörd under 2002 : Årsrapport till det nationella programmet för miljöövervakning av jordbruksmark, delprogram pesticider
- 2003
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Inom ramen för det nationella programmet för miljöövervakning av jordbruksmark har under 2002förekomsten av bekämpningsmedel undersökts i jordbruksbäckar från fyra typområden (dvs. småjordbruksdominerade avrinningsområden), i grundvatten från ett typområde, i två åar och i nederbördfrån en lokal.Varje vattenprov har analyserats på mellan 66 och 78 enskilda substanser (totalt 9 735 enskildamätningar). Av dessa var 56 substanser registrerade för försäljning i Sverige under 2002 och utgjordeca 90% av den totala försäljningen av ogräs-, svamp- och insektsmedel inom jordbruk och trädgård.De övriga substanserna som analyserades har antingen varit registrerade tidigare, men är fortfarandevanligt förekommande i svenska vatten och/eller finns upptagna som prioriterat ämne inom EU:sRamdirektiv för vatten. Några substanser är också nedbrytningsprodukter till vanligt förekommandeogräsmedel.
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| 23. |
- Johannesson, Karin M., 1982-, et al.
(författare)
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Clay-bound phosphorus retention in wetlands : a catchment comparison
- 2010
-
Ingår i: 6th International Phosphorus Workshop (IPW6). ; , s. 127-127
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ten constructed wetlands, situated in agricultural areas in the south of Sweden, are investigated for phosphorus (P) retention and factors affecting the efficiency. These wetlands are situated in areas dominated by clay or heavy clay soils. National monitoring and estimations have shown that agricultural areas dominated by such clay soils have among the highest phosphorus losses. It has also been shown that a large proportion of P is transported in particulate form; hence, it is expected that sedimentation is the predominant P retention process in the selected wetlands. Sedimentation of clay may, however, be difficult to achieve in wetlands, and the aim of the study is to quantify the function of wetlands as sinks for the P lost from the catchments. Sedimentation and accumulation of particles are measured once a year using sedimentation plates (40×40 cm) placed on the bottom of the wetlands. Additional sedimentation traps (estimating gross sedimentation) have been placed in three of the wetlands, and those are emptied two times per year. This paper presents results for P and soil retention after the first year (in kg P ha-1 year-1), estimated by extrapolating the amount of sediment accumulated on the plates, and the content of total phosphorus (TP), to the whole wetland area. Furthermore, one wetland was selected for a detailed investigation of the effect of a vegetation filter, which in a previous study has been shown to have a positive effect on particle retention. Here, estimates of net and gross sedimentation are measured before, within and after the vegetation filter. To identify some factors of significant importance for wetland P load and retention efficiency, the statistical relationship with different wetland and catchment characteristics is analyzed. The factors included are the ratio wetland area to catchment area, average hydraulic load, and various catchment characteristics, e.g. soil type, topography, fertilization history, and soil P fractions. Since there is some uncertainty regarding sedimentation of fine clay particles (< 0.2 m), the size fractions of the accumulated sediment is determined to see whether or not the finest clay particles from the catchments settle in the wetlands. Previous studies have shown a correlation between particle size and bioavailability, where finer clay particles contain larger proportion of easily available P. Trapping the finest clay particles is therefore of particular ecological importance and needs to be further investigated.
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| 24. |
- Johannesson, Karin M., 1982-, et al.
(författare)
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Phosphorus and particle retention in constructed wetlands—A catchment comparison
- 2015
-
Ingår i: Ecological Engineering. - Amsterdam : Elsevier. - 0925-8574 .- 1872-6992. ; 80, s. 20-31
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract Seven constructed wetlands (0.05–0.69 ha), situated in agricultural catchments (22–267 ha) in the south of Sweden, were studied for two years with two aims: to (i) quantify their function as sinks for particles and phosphorus (P) lost from the catchments, and (ii) investigate to what degree catchment and wetland characteristics and modeled loads (using hydrochemical catchment models) could be used to explain differences in retention between the wetlands. The wetland areas ranged from 0.04 to 0.8% of the respective catchment area, and they were situated in areas dominated by fine-textured soils with relatively high P losses and the main proportion of P transported in particulate form. Net P and particle retention were estimated during two years from annual accumulation of particles on sedimentation plates (40 × 40 cm) on the bottom of the wetlands.There was an annual net retention of particles and P, but with a large variation (for particles 13–108 t ha−1 yr−1 and for P 11–175 kg ha−1 yr−1), both between wetlands and between years. The difference between the two years was larger than the difference in mean P retention between the seven wetlands. There was a positive relationship between P and particle retention and three catchment factors, i.e. P status (P-AL) of agricultural soils, average slope in the catchments and the livestock density, and a negative relationship with the agricultural soil clay content. In addition, there was a positive relationship with the wetland length:width ratio. Contrary to expectations, neither the modeled hydraulic load nor P load was significantly correlated with the measured particle and P retention. There was also a positive relationship between P concentration in the sediment and soil P status in the catchment. The results imply that considerable errors are introduced when down-scaling modeled regional nutrient losses to estimate the P loads to small wetlands in agriculturally dominated catchments. A more qualitative approach, using catchment characteristics for identification of hot-spot fields, may be equally good to identify suitable locations for constructed wetlands to reduce diffuse P loads. © 2014 Elsevier B.V.
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| 25. |
- Johansson, Göran, et al.
(författare)
-
Observationsfält på åkermark : Avrinning och växtnäringsförluster för de agrohydrologiska åren 1999/00 och 2000/01 samt en långtidsöversikt
- 2002
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Samhället har såväl på ett nationellt plan som genom internationella överenskommelseruppställt klara miljömål för acceptabel inverkan på vattensystemen orsakade av bl. a. växtochanimalieproduktionen. Sektorsmål och åtgärdsprogram för reduktion av växtnäringsförlusterfrån jordbruk har upprättats (Jordbruksverket, 2000). Genom miljöövervakning kontrollerasgraden av måluppfyllelse, samtidigt som övervakningen interagerar medforskningen. Observationsfält på åkermark är en metod för att följa jordbrukets förändradeodlingsåtgärder och hur detta inverkar på kvalitén på det avrinnande vattnet frånjordbruksmarken.
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| 26. |
- Kjellin, Johan, 1978-
(författare)
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Coupled Hydrological and Microbiological Processes Controlling Denitrification in Constructed Wetlands
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Treatment wetlands play an important role in reducing nitrogen content in wastewater and agricultural run-off water. The main removal process is denitrification and the removal efficiency depends on the hydrological and microbiological features of the wetland, especially in terms of water residence times and denitrification rates. The aim of this thesis was to increase the understanding of the coupled hydrological and microbiological processes regulating the denitrification capacity. This was done by applying a broad spectrum of analyses methods, including tracer experiment, water flow modeling, denitrification rate measurements, and analyses of the microbial community structures. The tracer experiment and flow modeling revealed that the wetland design, especially the vegetation, largely can affect the water residence time distributions in wetlands. In the investigated wetland, vegetation dominated the water flow, explaining 60-80% of the variance in water residence times, whereas basin shape only explained about 10% of the variance, but also mixing phenomena significantly affected the residence times and could considerably delay solutes. Measured potential denitrification rates in the wetland exhibited significant spatial variations, and the variations were best described by concentration of nitrogen in sediments and water residence time. Analyses of the denitrifying bacteria populations indicated that a few key populations dominated and that the community diversity increased with decreasing nutrient levels and increasing water residence times. Moreover, it was found that denitrification rates in terms of Menten and first order kinetics can be evaluated by fitting a mathematical expression, considering denitrification and other nitrogen transforming processes to measured product formation in nitrate limited experiments.
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| 27. |
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| 28. |
- Kreuger, Jenny; Törnquist, Mirja; Ulén, Barbro,
(författare)
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Förekomst av bekämpningsmedel i svenska vatten 1985-2001
- 2002
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 1. SammanfattningEn databas innehållande analyser av bekämpningsmedel i yt-, grund- och dricksvatten i Sverigefrån åren 1985 till 2001 har sammanställts för att försöka skapa en överblick av hur situationenser ut och hur den har förändrats över tiden. Totalt innehåller den data om 5352 st prover frånsamtliga län och 197 kommuner. Undersökningarna har utförts av kommuner, länsstyrelser,vattenvårdsförbund, Livsmedelsverket, SLU samt ytterligare några aktörer.Den använda mängden bekämpningsmedel har minskat i Sverige sedan mitten av 80-talet för attde senaste åren öka något igen. Tittar man på hektardoserna, dvs hur många hektar den försåldamängden räcker till, blir uppgången tydligare. Ökningen anses hänga samman med EU-inträdet1995.
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| 29. |
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| 30. |
- Kyllmar, Katarina, et al.
(författare)
-
Riskfaktorer för fosforförluster samt förslag på motåtgärder i tre avrinningsområden inom pilotprojektet Greppa Fosforn
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tre jordbruksdominerade avrinningsområden (N33 i Halland, E23 i östergötland och U8 i Västmanland) ingår sedan 2007 i pilotprojektet Greppa Fosforn. Projektet är ett samarbete mellan lantbrukare, rådgivare, länsstyrelser, Jordbruksverket samt SLU, och syftar till att utveckla ett arbetssätt för att på effektivaste sätt minska fosforförlusterna från jordbruket inom ett avrinningsområde och praktiskt prova om de åtgärder vi känner till i dag kan påverka fosforförlusterna från åkermarken. I denna rapport redovisas ett delprojekt där ett antal riskfaktorer för fosforförluster har identifierats i de tre pilotområdena och förslag på åtgärder har tagits fram. Delprojektet har genomförts som en expertbedömning i grupp med områdessamordnaren för respektive pilotområde samt forskare vid SLU. Som underlag har gruppen haft redan tillgängliga data från undersökningarna i pilotområdena samt modellerade kartor över risker för ytavrinning, erosion och stillastående vatten som tagits fram inom delprojektet. För bedömningen av risker togs en matris fram med tänkbara riskfaktorer som gruppen värderade. På samma sätt gjordes en matris med åtgärder som bedömdes. Både risker och åtgärder delades in i tre grupper, sådant som rör (1) odling och växtföljder; (2) fältets egenskaper; samt (3) förhållanden i vattendraget. Resultaten visade att i pilotområdet i Västmanland var ett flertal av riskfaktorerna åtgärdade medan det återstår en del arbete i de två andra områdena. Riskfaktorer i pilotområde N33 (Halland) och i pilotområde E23 (östergötland) är fält med begränsad genomsläpplighet i marken och dräneringssystem med nedsatt funktion. Här föreslås åtgärder för att förbättra markens struktur som justering i jordbearbetningsstrategin, alvluckring, ändrade växtföljder, strukturkalkning men också underhåll av dräneringssystem. I samtliga pilotområden bör stallgödsling av fält med höga fosfortal i marken undvikas. Något som också uppmärksammades var förekomsten av branta bäckkanter som lätt kan eroderas. I samband med dikesrensning bör bäckkanterna släntas av så att lutningen minskar och en skyddande grässvål kan etableras. En skyddszon bör också anläggas så att plöjning nära bäckkanten förhindras, vilket skulle minska risken för ras vid ytavrinning. Vegetationsfilter bör även anläggas kring ytvattenbrunnar och på åkermark där det ofta är stående vatten. I delprojektet ingick inte att kvantifiera storleken i påverkan av olika riskfaktorer och inte heller i de föreslagna åtgärdernas effekt. Därmed har inte heller kostnadseffektiviteten i åtgärderna bedömts. Vi ser dock att arbetssättet skulle kunna användas generellt av lantbrukare i landet för att göra en självvärdering av riskfaktorer och tänkbara åtgärder på den egna gårdens mark. Det skulle vara ett effektivt sätt att lokalisera riskområden och möjliga åtgärder i landskapet. Om dessutom många av de mer enkla åtgärderna genomförs kan det ha stor betydelse även om effekten av varje enskild åtgärd inte är helt känd. Att lantbrukaren själv har gjort bedömningen av sin mark är av största vikt i ett effektivt åtgärdsarbete.
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| 31. |
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| 32. |
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| 33. |
- Linefur, Helena, et al.
(författare)
-
Lime placement on subsoil as a strategy to reduce phosphorus leaching from agricultural soils
- 2016
-
Ingår i: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 32, s. 381-389
-
Tidskriftsartikel (refereegranskat)abstract
- Leaching of phosphorus (P) from agricultural land is a major contributor to eutrophication of surface waters in many countries, and effective mitigation options to reduce P in leachate are needed. In this study, intact columns (0.77 m deep) of subsoil from three Swedish agricultural soils (one sand and two clay) were used to examine whether placing quicklime (calcium oxide, CaO) on the subsoil could reduce P leaching over a 3-yr period. Leaching of particulate P (PP) was significantly less from clay soil columns with lime than from clay soil columns without (P < 0.001 and P < 0.05, respectively), with a relative reduction of 49 and 51% in the two soils. Leaching of dissolved reactive P (DRP) was less from sand columns with lime than from sand columns without, although not significantly so due to large variation in P leaching between columns. These results indicate that placement of lime on subsoil has potential to reduce P leaching, especially of PP from clay soils. However, more studies including both topsoil and subsoil and a range of soil types are needed to assess the full potential of this P mitigation option.
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| 34. |
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| 35. |
- Linefur, Helena, et al.
(författare)
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Topsoil and Subsoil Properties Influence Phosphorus Leaching from Four Agricultural Soils
- 2013
-
Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425 .- 1537-2537. ; 42, s. 455-463
-
Tidskriftsartikel (refereegranskat)abstract
- Eutrophication, a major problem in many fresh and brackish waters, is largely caused by nonpoint-source pollution by P from agricultural soils. This lysimeter study examined the influence of P content, physical properties, and sorption characteristics in topsoil and subsoil on P leaching measured during 21 mo in 1-m-long, undisturbed soil columns of two clay and two sandy soils. Total P losses during the period varied between 0.65 and 7.40 kg ha(-1). Dissolved reactive P was the dominant form in leachate from the sandy soils and one clay soil, varying from 48 to 76%. Particulate P dominated in leachate from the other clay soil, where low pH (5.2) in the subsoil decreased aggregate stability and thereby probably increased the dispersion of clay particles. Phosphorus leaching was small from soils with high P sorption index (PSI) and low P saturation (<10% of PSI) in the subsoil, even though extractable P (Olsen P) in the topsoil was high, and large from a soil with low sorption capacity and high P saturation (>35% of PSI) in the profile. High sorption capacity in the subsoil was more important for P leaching in sandy soils than in clay soils with macropore flow, where the effect of high sorption capacity was reduced due to less interaction between percolating water and the soil matrix. The results suggest that P leaching is greatly affected by subsoil properties and that topsoil studies, which dominate current research, are insufficient for assessing P leaching in many soils.
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| 36. |
- Liu, Jian, et al.
(författare)
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Biomass production and phosphorus retention by catch crops on clayey soils in southern and central Sweden
- 2015
-
Ingår i: Field Crops Research. - : Elsevier BV. - 0378-4290 .- 1872-6852. ; 171, s. 130-137
-
Tidskriftsartikel (refereegranskat)abstract
- Catch crops are a potential option to reduce phosphorus (P) losses, but little is known about their establishment success and capacity to retain P on clayey soils in regions with short autumns, e.g. Sweden. This study screened biomass production and P retention by eight catch crop species: the perennials chicory (Cichorium intybus L), cocksfoot (Dactylis glomerata L), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L) and the annuals phacelia (Phacelia tanacetifolia L), white mustard (Sinapis alba L), oilseed radish (Raphanus sativus L oleiformis) and white radish (R. longipinnatus). The catch crops were grown at six field sites, where the perennial species were under-sown with barley and the annual species were after-sown following barley harvest. Biomass production, P content in above-ground and below-ground plant parts and content of available P in the soil were determined in autumn and survival rate of the catch crops in the following spring. Biomass production and P retention in autumn both differed significantly between species (p < 0.0001), and were greatly affected by site-specific conditions and time of sowing, which differed between experiments. Growth of catch crops can also be suppressed by low precipitation. Content of P in roots varied substantially between species, a factor which must be considered in species comparisons. The under-sown species produced more or equivalent amounts of biomass, retained more or equivalent amounts of P in autumn and survived better over winter than the after-sown species. Thus under-sown catch crops generally seem more suitable as catch crops for P. (C) 2014 Elsevier B.V. All rights reserved.
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| 37. |
- Liu, Jian, et al.
(författare)
-
Catch crops for phosphorus
- 2010
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Catch crops have successfully been used to mitigate losses of nitrogen (N) from agricultural land, but their impacts on phosphorus (P) losses are uncertain. Cultivating catch crops of appropriate species and varieties may effectively reduce P losses through surface runoff and erosion by increasing water infiltration and improving soil structure. In addition, catch crops may act as a sink of plant-available P after the main crop has been harvested. Opposite, they may act as a source, since P may leach from the very plant cells e.g. when destroyed by frost. This is of great concern for Nordic countries with cold winter climate and many freezing-thawing cycles of the soil. As a part of the understanding of the role of plant, including those on buffer strips, for P retention, the leaching from some selected plants are studied after freezing and thawing the whole plants including the soil. In laboratory P leaching from various potential catch crops after a problematic winter climate is simulated through seven repeated freezing-thawing cycles. Lysimeters with five plants representing two different clay soils from two climatic regions in Sweden are used. The plants presently tested are: English ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), oil radish (Raphanus sativus L.), phacelia (Phacelia tanacetifolia L.) and chicory (Cichorium intybus L.). In each cycle, the plants and soils are frozen 12 hours at -18oC and thawed another 12 hours at +18oC. The soil columns (20 cm in diameter × 25 cm in height) are repeatedly irrigated with a total of 70 mm water, with the intensity of10 mm∙h-1, before and after freezing-thawing cycles. Basic soil physical and chemical properties, P content in plant, and dissolved reactive P (DRP), particulate bound P (PP) and total P (TP) in the water leachate are analyzed as well.
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| 38. |
- Liu, Jian, et al.
(författare)
-
Catch crops to mitigate phosphorus leaching under cold climate
- 2012
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Nutrient leaching from agricultural land contributes greatly to the eutrophication of recipient water bodies. Catch crops (cover crops) used for reducing nitrogen leaching are proposed to mitigate phosphorus (P) leaching too. However, in regions with winter frost, catch crops may act as a source of P losses after plant cell lysis. A field study on two clay soils in south Sweden in 2009-2012 examined eight potential P catch crops; chicory (Cichorium intybus L.), cocksfoot (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), red clover (Trifolium pretense L.), phacelia (Phacelia tanacetifolia L.), white mustard (Sinapis alba L.), and radish (Raphanus sativus L.) with the latter represented by both R. oleiformis and R. longipinnatus. Soil columns with catch crops and controls were collected in late autumn and used in leaching experiments. The columns were undergone seven repeated freezing-thawing cycles (FTCs) in the laboratory and irrigated with 70 mm simulated rainfall both before and after FTCs. The P content in leachate was analyzed after each irrigation. Leaching of total-P increased after FTCs compared with before (p=0.045) and varied significantly with year (p<0.0001) and species (p=0.037). Chicory and white mustard had lower total-P leaching than the control, while radish (R. oleiformis) and red clover had highest total-P leaching of all species. Ryegrass and radish (R. oleiformis) were the most sensitive species to frost in terms of causing the largest increase in total-P concentrations compared with the control. Radish (R. longipinnatus), cocksfoot, and chicory were the least sensitive crops and caused no significant increase in P leaching after FTCs. It was concluded that the effect of catch crops on P leaching differs between years and that perennial ryegrass, commonly grown as a catch crop in the Nordic countries, tends to leach more P than other potential catch crops after exposure to severe frost.
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| 39. |
- Liu, Jian, et al.
(författare)
-
Freezing-thawing effects on phosphorus leaching from catch crops
- 2014
-
Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 99, s. 17-30
-
Tidskriftsartikel (refereegranskat)abstract
- It is suggested that catch crops can be grown to reduce phosphorus (P) losses. However, after exposure to freezing-thawing cycles (FTCs), catch crop material can become a source of P losses to waters in moderately cold climates. This study screened potential P leaching from intact plant material of eight catch crop species: chicory (Chichorium intybus L.), cocksfoot (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), red clover (Trifolium pratense L.), phacelia (Phacelia tanacetifolia L.), white mustard (Sinapis alba L.), oilseed radish (Raphanus sativus L. oleiformis), and white radish (R. longipinnatus). The catch crops were grown in six field experiments on clay soils, where soil lysimeters (0.25 m deep) with intact crops were extracted in autumn and after used for leaching experiments before and after seven FTCs in the laboratory. The eight catch crops did not reduce P leaching before FTCs. After FTCs, leachate total-P concentration from ryegrass, oilseed radish and red clover lysimeters were significantly (p=0.0022) higher than those from the other species and the control without a catch crop. FTCS significantly (p= 0.0064) altered total-P concentration and the proportions of different forms of P. There was a significant increase in total-P concentration in leachate from ryegrass (p=0.0008) and oilseed radish (p= 0.02). Thus, the potential risk of P leaching from ryegrass and oilseed radish material after FTCs must ne considered, since they are commonly grown as nitrogen catch crops in the Nordic countries. Morever, the roots of the tested catch crops contained 7-86 % total-P, which is important when ealuating O leaching risks.
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| 40. |
- Liu, Jian, et al.
(författare)
-
Phosphorus leaching from a clay and sandy soil supplied with manure and mineral fertilizer
- 2012
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) leaching from agricultural fields contributes to eutrophication of adjacent water bodies. The complexity among factors controlling P leaching losses requires careful consideration in designing effective mitigation strategies. We studied P leaching (both total-P and dissolved reactive P) from lysimeters filled with clay or sandy topsoil before and after addition of 30 kg P ha-1 in the laboratory. The clay lysimeters were collected from a field with separately tile-drained plots and the results were compared with data from that field. The topsoils were treated with different sources of P (pig slurry or mineral P), which were either surface applied or incorporated into the soil. The initial total-P concentrations in lysimeter leachate were lower from the clay soil (0.13 mg L-1) than from the sandy soil (0.21 mg L-1), but in the clay soil they increased considerably after slurry application, to 1.39 mg L-1 for incorporated slurry and 2.76 mg L-1 for surface-applied slurry. The field study on the clay soil confirmed that surface-applied slurry increases P leaching under certain conditions. Critical events in the crop rotation were application in autumn on the soil surface, after cereals or on grass/clover, while spring application did not increase P leaching. Thus time of application and incorporation of slurry after application may be important for reducing P losses from clay soils.
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| 41. |
- Liu, Jian, et al.
(författare)
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Potential of phosphorus (P) release from eight catch crops
- 2011
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Growing catch crops (cover crops) is an important option to mitigate nitrogen (N) leaching losses in the late autumn and in winter after harvest of the main crop. However, their efficiency in leaching losses of dissolved reactive phosphorus (DRP) and dissolved organic phosphorus (DOP) is uncertain and may vary between crop species and varieties. The crop and root may act as sources of P when the plant cells are burst by frost which is of special concern for countries with cold winter climate and many freezing-thawing cycles. A green house experiment was carried out to study the potential of P release from 8 catch crops: English ryegrass (Lolium perenne L.), cocks foot (Dactylis glomerata L.), chicory (Cichorium intybus L.), red clover (Trifolium pretense L.), white mustard (Sinapis alba L.), phacelia (Phacelia tanacetifolia L.), oilseed radish (Raphanus sativus L. var. Oleiformis), and a variety of the latter specie, structurator (Raphanus sativus L. var. Longipinnatus). The root and shoot parts of the catch crops were separated at harvest. The roots were scanned for the morphology parameters: total length, total surface area, and specific surface area. Dissolved reactive P (DRP) and total P (TP) were extracted with water from root and shoot samples which had undergone different freezing (-thawing) cycle modes. Extractions (including control) were made after 4 continuous freezing-thawing cycles, after each of the 4 continuous freezing-thawing cycles, and after 3 continuous freezing days and l thawing day. The results were evaluated together with a laboratory leaching experiment with topsoil lysimeters and natural grown catch crops.
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| 42. |
- Liu, Jian, et al.
(författare)
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Potential phosphorus leaching from sandy topsoils with different fertilizer histories before and after application of pig slurry
- 2012
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Ingår i: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 28, s. 457-467
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effects of historical long-term and recent single applications of pig slurry on P leaching from intact columns of two sandy topsoils (Mellby and Böslid). The soils had similar physical properties, but different soil P status (ammonium lactate-extractable P; P-AL) and degree of P saturation (DPS-AL). Mellby had P-AL of 220-280 mg kg-1 and DPS-AL of 32-42%, which was higher than for Böslid (P-AL 140 mg kg-1 and DPS 21%). The study investigated the effects since 1983 of four treatments with different fertilizer histories, in summary high (HighSlurryMellby) and low (LowSlurryMellby) rates of pig slurry and mineral P (MinMellby) applications at Mellby and mineral P application at Böslid (MinBöslid). The columns were irrigated in the laboratory five times before and five times after a single application of pig slurry (22 kg P ha-1). Concentrations of dissolved reactive P (DRP), dissolved organic P and total-P (TP) in leachate and loads were significantly higher (p <0.005) from the treatments at Mellby than those at Böslid. TP concentrations followed the trend: HighSlurryMellby (0.57-0.59 mg L-1) > MinMellby (0.41-0.49 mg L-1) > LowSlurryMellby (0.31-0.36 mg L-1) > MinBöslid (0.14-0.15 mg L-1), both before and after the single slurry application. DRP concentrations in leachate were positively correlated with DPS-AL values in the topsoil (R2=0.95, p<0.0001), and increased with greater DPS-AL values after the single slurry application (R2=0.79, p<0.0001). Thus, DPS-AL can be an appropriate indicator of P leaching risk from sandy soils. Moreover, the build-up of soil P due to long-term repeated manure applications seems to be more important for potential P losses than a single manure application.
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| 43. |
- Liu, Jian, et al.
(författare)
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Potential phosphorus release from catch crop shoots and roots after freezing-thawing
- 2013
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 371, s. 543-557
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims Catch crops used for mitigating nutrient losses to water can release phosphorus (P) when exposed to repeated freezing-thawing cycles (FTCs). This study sought to evaluate potential P losses from shoots and roots of eight catch crops. Methods Shoots and roots sampled from perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), chicory (Cichorium intybus L.), phacelia (Phacelia tanacetifolia L.), red clover (Trifolium pratense L.), white mustard (Sinapis alba L.), oilseed radish (Raphanus sativus var. oleiformis L.) and white radish (R. sativus var. longipinnatus L.) were treated with no freezing, one single FTC, four continuous FTCs and four discontinuous FTCs. All samples were analysed for water-extractable P (WEP), and root samples also for characteristics such as specific root surface area (SSA). Results Freezing-thawing significantly increased potential P losses from both shoots and roots compared with no freezing. The two radish species and white mustard contained significantly higher concentrations of WEP than the other species, among which chicory and phacelia had the lowest WEP. On average, shoots had 43% higher WEP than roots. Cumulative P release from shoots and roots was strongly correlated with their total-P content (p=0.006 and p=0.002, respectively). Cumulative release of P from taproots was correlated with SSA (p=0.03). Conclusions Chicory, and possibly phacelia, appear to be promising catch crops for P.
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| 44. |
- Norberg, Lisbet, et al.
(författare)
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Strukturkalkning för minskat fosforläckage – En fältstudie på mellanlera i Halland
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fältstudien utfördes på Hushållningssällskapets försöksgård Lilla Böslid i Halland. I försöket studerades strukturkalkning med 8 och 16 ton/ha av fuktig blandprodukt (Fostop, Nordkalk), i jämförelse med okalkad mark (kontroll) på ett försöksfält med specialdränerade rutor. Dräneringsvattnet från varje enskild ruta leddes via ett dräneringsrör till mätstationen där vattenflödet mättes kontinuerligt och koncentrationen av totalfosfor, fosfatfosfor, totalkväve och turbiditet i det avrinnande vattnet analyserades. Försöket kalkades i september 2018 och utlakningsmätningarna påbörjades så fort avrinningen kom igång och pågick sedan över två vintrar fram till och med januari 2021. Jordarten på försöksfältet är en mellanlera med i genomsnitt 29% lerhalt (26-33) i matjorden (0-30 cm) och något högre i alven. I övrigt dominerar kornstorlekarna mo och mjäla. Lerfraktionerna består till största delen av svällande mineral. Jordprover för test av aggregatstabiliteten togs på våren 2019 och 2020 då jord från det översta lagret sållades för att få fram jord i aggregatklassen 2-5 mm. Dessa aggregat utsattes sedan för regn i en regnsimulator och det avrunna vattnet analyserades för elektrisk konduktivitet och turbiditet. I samband med uttaget av jordprover till aggregatstabilitet togs även matjordsprover (0-20 cm) ut för analys av pH, Ca-AL och elektrisk konduktivitet. Fältförsöket har inte påvisat några statistiska skillnader mellan kontrolledet utan kalk och de två leden med 8 respektive 16 ton kalkgiva/ha, avseende utlakning av totalfosfor, fosfatfosfor, kväve och turbiditet i dräneringsvattnet. Andra året uppvisade dock en tydlig tendens till minskad utlakning av totalfosfor (40%) och turbiditet med strukturkalkning. Andra årets tendens till minskad utlakning av totalfosfor visar också att skillnaden mellan kalkgivorna 8 och 16 ton/ha var små vilket tyder på att en större mängd kalkblandning inte ger en större effekt på utlakningen från den här jorden. Under det tredje årets början planade dock tendensen ut och inga skillnader mellan leden kunde ses. Ytjordens struktur, i form av aggregatstabilitet mätt som turbiditet och EC i dräneringsvattnet från jordprover som utsatts för simulerat regn, förändrades inte till följd av strukturkalkningen. Matjordens pH var högre i de kalkade leden jämfört med kontrolledet båda åren medan EC och Ca-AL hade statistiskt högre värden andra året och en tendens till högre värden första året. Skörden av vårkorn tenderade att bli högre med ökad kalkgiva men kärnans innehåll av P och N påverkades inte av kalkningen. Mätningarna av utlakningen skulle behöva följas upp under flera år framöver, för att kunna se om strukturkalkningen får effekt på längre sikt eller ger effekt främst under förhållanden med stor partikeltransport, eller om effekten är fördröjd genom långsammare reaktioner mellan kalk och ler än väntat.
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| 45. |
- Parvage, Masud, et al.
(författare)
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A survey of soil phosphorus (P) and nitrogen (N) in Swedish horse paddocks
- 2013
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Ingår i: Agriculture, Ecosystems and Environment. - : Elsevier BV. - 0167-8809 .- 1873-2305. ; 178, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Of the EU countries, Sweden utilizes the highest proportion (10%) of its total agricultural land for horses. Horse paddocks commonly hold horses on a limited space, in the present study at a rate of 5-14 livestock units ha(-1). Thus these paddocks receive significant amounts of phosphorus (P) and nitrogen (N) through feed residues and deposition of faeces and urine, which can lead to nutrient build-up in the soil. This study examined soil P and N status in different parts of horse paddocks (feeding, grazing and excretion areas) and compared it with that in adjacent, unmanaged reference soils. The paddock areas were then categorized with respect to environmental risk using the threshold concentrations of plant-available P extracted with ammonium acetate lactate solution at pH 3.75 (P-AL) and total N set by the Swedish Environmental Protection Agency. In total, seven horse farms, covering different grazing densities and soil textures representative of Swedish horse paddocks, were examined. The results showed that concentrations of water-soluble P (WSP), P-AL, and total N were highest in feeding and excretion areas within the paddocks. Weighted concentrations of soil P for the whole paddocks amounted to 2.9-10.5 mg WSP (kg(-1)) and 35-224 mg P-AL (kg(-1)), and were higher than in the corresponding reference fields (0.8-4.9 mg WSP (kg(-1)) and 17-102 mg P-AL (kg(-1))). The WSP concentration in the paddocks was strongly correlated with horse density (R-2 = 0.80***(1), n = 13) and P-AL with years of paddock management (R-2 = 0.78***, n = 13). Total organic C was significantly correlated with P-AL, total P and total N in the feeding and excretion areas. The degree of soil P saturation (DPS) concentrations was important soil parameters determining WSP concentration in the paddocks (R-2 = 0.63***, n = 110), whereas total P concentration in soils was determining P-AL concentrations (R-2 = 0.82***, n = 112). According to Swedish environmental guidelines, two of the seven farms studied posed a high risk and three a moderate risk of extensive P leaching losses, but the risk of extensive N losses was moderate for all farms studied. As regards the specific sections of the paddock, the feeding and excretion areas had the highest risk of P leaching losses. Thus paddock soils can be high-risk areas for P leaching comprising about 3.85% of the total high-risk land area in Sweden. (c) 2013 Elsevier B.V. All rights reserved.
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| 46. |
- Parvage, Masud, et al.
(författare)
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Are horse paddocks threatening water quality through excess loading of nutrients?
- 2015
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 147, s. 306-313
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Tidskriftsartikel (refereegranskat)abstract
- The Baltic Sea is one of the most eutrophied water bodies in northern Europe and more than 50% of its total anthropogenic waterborne phosphorus (P) and nitrogen (N) loads derive from agricultural sources. Sweden is the second largest contributor of waterborne N and the third largest contributor of waterborne P to the Baltic Sea. Horse farms now occupy almost 10% of Swedish agricultural land, but are not well investigated with regard to their environmental impact. In this study, potential P, N and carbon (C) leaching losses were measured from two representative horse paddock topsoils (0-20 cm; a clay and a loamy sand) following simulated rainfall events in the laboratory. Results showed that the leachate concentrations and net release of P, N and dissolved organic C (DOC) from paddock topsoils were highest in feeding and excretion areas and considerably higher from the loamy sand than the clay paddock topsoil. Leaching losses of dissolved reactive P (DRP) were significantly (p < 0.05) correlated with concentrations of water-soluble P and ammonium acetate lactate-extractable P (P-AL) in the soil, while leaching losses of dissolved organic P and total organic N were significantly correlated with DOC concentration in leachate. Leaching loads of P and N from paddock topsoils greatly exceeded average figures for Swedish agricultural topsoils. It was concluded that: i) horse paddocks pose a potential threat to water quality via leaching of excess P and N, ii) feeding and excretion areas are potential hotspots for highly enhanced leaching losses, and iii) paddocks established on sandy soils are particularly susceptible to high N leaching losses.
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| 47. |
- Parvage, Masud, et al.
(författare)
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Can organic materials reduce excess nutrient leaching from manure-rich paddock soils?
- 2017
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Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425 .- 1537-2537. ; 46, s. 105-112
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Tidskriftsartikel (refereegranskat)abstract
- Horse paddocks have been identified as a significant contributor of animal waste nutrients to natural waters; thus, modified paddock management is needed. Because chemical amendments pose a health risk to horses, an alternative for reducing nutrient translocation from manure is to add available organic residues to the soil. To examine the feasibility of outdoor use of organic materials to reduce nutrient losses from paddock soils, three commonly available organic materials (peat, wheat straw, and wood chips) were tested for their nutrient retention capacities in batch experiments followed by leaching experiments in an in-house lysimeter station using artificial rainfall. Results showed that the grounded peat and wood chips retained some phosphorus (P), whereas grounded wheat straw released P to the solution. In leaching experiments, peat reduced nitrogen (N) losses by 40% but increased P and carbon (C) losses severalfold. Wheat straw was ineffective in reducing P, N, or C losses and in some cases increased the losses. Wood chips effectively reduced P and C losses, by 70 and 40%, respectively, but not N losses. It was concluded that, among the three organic materials, only the wood chips can be used outdoors to reduce nutrient losses from paddock soils.
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| 48. |
- Parvage, Masud, et al.
(författare)
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Impact of horse grazing and feeding on phosphorus concentrations in soil and drainage water
- 2011
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Ingår i: Soil Use and Management. - : Wiley. - 0266-0032 .- 1475-2743. ; 27, s. 367-375
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Tidskriftsartikel (refereegranskat)abstract
- The number of horses in Sweden has increased, from 77 300 in 1970 to 283 000 in 2003 (ca. 250%). These horses are kept on 300 000 ha, which represents 10% of total agricultural land in Sweden. Maximum recommended livestock density in Sweden is 2.5 units/ha for grazed pasture, but no limits have yet been set for outdoor keeping and feeding areas (paddocks) for horses. This study characterized the potential risk of phosphorus (P) losses from a horse paddock established on a heavy clay soil with a stocking rate of 3.75 livestock units/ha compared with nearby arable land. The horse paddock received 15 kg P/ha/yr and 75 kg N/ha/yr through horse excreta, while annual input of P and N to the adjacent arable land was 13 and 112 kg/ha, respectively. There was no significant difference in water-soluble P (WSP) in fresh and dried soil samples between the horse paddock (mean values: 0.62 and 0.43 mg/100 g soil; n = 15) and the arable field (mean values: 0.52 and 0.37 mg/100 g soil; n = 5). In contrast, phosphorus extractable in ammonium acetate lactate (extractable P) in the topsoil of the horse paddock (mean: 15 mg/100 g soil) was significantly higher (P = 0.03; n = 15) than in the arable land, whereas total P extracted with nitric acid (total P) showed no statistically significant differences. Furthermore, there was no significant difference in lactate-extractable iron and aluminium (extractable Fe and Al), organic carbon (C), total nitrogen (N) or phosphorus sorption index between the two parcels of land. However, the degree of P saturation in soil was significantly higher (P = 0.02; n = 15) in the horse paddock. Extractable Al and Fe were highly correlated to extractable P (P < 0.001; n = 69), the correlation being negative for Al. No relationship was found with calcium, but soil C content was found to be correlated with extractable P (P < 0.001; n = 69). Over the past 8 yr, high P concentrations (up to 1.5 mg/L), mainly in dissolved reactive form, have been recorded in drainage water from the grazed catchment. We concluded that horse grazing at high stocking rates (> 2.5 livestock units/ha) may pose a risk of high P losses to nearby water bodies.
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| 49. |
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| 50. |
- Parvage, Masud, et al.
(författare)
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Phosphorus availability in soils amended with wheat residue char
- 2013
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Ingår i: Biology and Fertility of Soils. - : Springer Science and Business Media LLC. - 0178-2762 .- 1432-0789. ; 49, s. 245-250
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Tidskriftsartikel (refereegranskat)abstract
- Plant availability and risk for leaching and/or runoff losses of phosphorus (P) from soils depend among others on P concentration in the soil solution. Water-soluble P in soil measures soil solution P concentration. The aim of this study was to understand the effect of wheat residue char (biochar) addition on water-soluble P concentration in a wide range of biochar-amended soils. Eleven agricultural fields representing dominant soil texture classes of Swedish agricultural lands were chosen. Concentrations of water-soluble P in the soils and in biochar were measured prior to biochar incorporation to soils in the laboratory. Experiments with three dominant soil textures-silt loam, clay loam, and an intermediate loam soil with different rates of biochar addition (i.e., 0.5, 1, 2, and 4 %; w/w) showed that the highest concentration of water-soluble P was achieved at an application rate of 1 %. At higher application rates, P concentrations decreased which coincided with a pH increase of 0.3-0.7 units. When the 11 soils were amended with 1 % (w/w) biochar, water-soluble P concentrations increased in most of the soils ranging from 11 to 253 %. However, much of the water-soluble P added through the biochar was retained (33-100 %). We concluded that wheat residue char can act as a source of soluble P, and low and high additions of biochar can have different effects on soil solution P concentration due to possible reactions with Ca and Mg added with biochar.
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