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Träfflista för sökning "WFRF:(Torstensson Gunnar) srt2:(2010-2014)"

Sökning: WFRF:(Torstensson Gunnar) > (2010-2014)

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1.
  • Aronsson, Helena, et al. (författare)
  • Effects of pig and dairy slurry application on N and P leaching from crop rotations with spring cereals and forage leys
  • 2014
  • Ingår i: Nutrient cycling in agroecosystems. - : Springer Science and Business Media LLC. - 1385-1314 .- 1573-0867. ; 98, s. 281-293
  • Tidskriftsartikel (refereegranskat)abstract
    • Two crop rotations dominated by spring cereals and grass/clover leys on a clay soil were studied over 2 years with respect to nitrogen (N) and phosphorus (P) leaching associated with pig or dairy slurry application in April, June and October. Leaching losses of total N (TN), total P (TP), nitrate-N and dissolved reactive P (DRP) were determined in separately tile-drained field plots (four replicates). Mean annual DRP leaching after October application of dairy slurry (17 kg P ha(-1)) to growing grass/clover was 0.37 kg ha(-1). It was significantly higher than after October application of pig slurry (13 kg ha(-1)) following spring cereals (0.16 kg ha(-1)) and than in the unfertilised control (0.07 kg P ha(-1)). The proportion of DRP in TP in drainage water from the grass/clover crop rotation (35 %) was higher than from the spring cereal rotation (25 %) and the control (14 %). The grass/clover rotation proved to be very robust with respect to N leaching, with mean TN leaching of 10.5 kg ha(-1) year(-1) compared with 19.2 kg ha(-1) year(-1) from the cereal crop rotation. Pig slurry application after cereals in October resulted in TN leaching of 25.7 kg ha(-1) compared with 7.0 kg ha(-1) year(-1) after application to grass/clover in October and 19.1 kg ha(-1) year(-1) after application to spring cereals in April. In conclusion, these results show that crop rotations dominated by forage leys need special attention with respect to DRP leaching and that slurry application should be avoided during wet conditions or combined with methods to increase adsorption of P to soil particles.
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2.
  • Aronsson, Helena, et al. (författare)
  • N and P losses from two crop rotations on a clay soil with applications of liquid manure
  • 2011
  • Ingår i: NJF Report. - 1653-2015. ; 7, s. 102-105
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In Sweden, nitrogen (N) and phosphorus (P) leaching losses and mitigation strategies for cropping systems using liquid manure have been studied on sandy soils, e.g. at Mellby experimental field in southern Sweden (Halmstad, 7.2 oC and 803 mm) (Torstensson & Aronsson, 2000). In 2008, a corresponding experiment was established on a clay soil in a neighbouring field (Lilla Böslid; 30% clay) in order to enable estimations of leaching and recommendations relating to the use of pig and cattle slurry for clay soils in this region. The field consists of 36 separately tile-drained plots with flow-proportional water sampling for estimations of nutrient leaching. Two crop rotations, representing pig and dairy production, are being studied, including control plots (Table 1). The main objectives of the studies, which started in 2010, are to: 1) quantify P leaching from this soil, 2) determine how N and P leaching is affected by time of slurry application to different crops (with and without incorporation) and 3) identify possibilities for improving N and P use efficiency on farms with intensive livestock production. Transport of dissolved dinitrous oxide in drainage water is also being measured in a connected project together with Halmstad University. The study is being funded by the Swedish Farmers' Foundation for Agricultural Research.
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3.
  • Geranmayeh, Pia, et al. (författare)
  • Phosphorus Retention in a Newly Constructed Wetland Receiving Agricultural Tile Drainage Water
  • 2013
  • Ingår i: Journal of Environmental Quality. - : Wiley. - 0047-2425 .- 1537-2537. ; 42, s. 596-605
  • 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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4.
  • Mogren, Lars, et al. (författare)
  • Improved Nitrogen Starter Fertilizer Strategy (Method and Level) for Field Grown Iceberg Lettuce (Lactuca sativa)
  • 2010
  • Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 852, s. 305-310
  • Konferensbidrag (refereegranskat)abstract
    • The paper presents three preliminary trials of a study with the aim to find a way to reduce total amounts of nitrogen applied in iceberg lettuce (Lactuca sativa) production without reducing the yield and quality by the use of a starter fertilizer strategy. The trials consisted of a fertilizer experiment, a demonstration plot and a trial in climate chamber conditions. Levels, total amounts and methods of nitrogen fertilizer application were compared. Low to medium levels of nitrogen added as placed starter fertilizer resulted in equal yield and lettuce quality compared to high levels and broadcast application. This means that the total amount of nitrogen fertilizer can probably be lowered and thereby the risk of nitrogen leaching from the field. No statistically significant reduction in yield or quality between broadcast and placed fertilizer treatments were found, so the placed starter fertilizer method seems promising, but need to be further tuned for Swedish climate conditions
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5.
  • Neumann, Angelika, et al. (författare)
  • Identification of key factors for reducing N and P leaching from organic crop rotations
  • 2011
  • Konferensbidrag (refereegranskat)abstract
    • Leaching of nitrogen (N) and phosphorus (P) for different 6-year organic crop rotations was examined in separately tile-drained field plots on two different sites in southwest Sweden. On each site, two different farming systems, one with dairy cows and one without stock, were evaluated to identify parts of the crop rotations with the greatest risks of N and P leaching and to examine the scope for improvement. Although organic farming methods themselves already led to a reduction in nutrient leaching, critical periods in the crop rotation could nevertheless be identified for the two soil types. While P leaching is of major importance on clay soils, sandy soils are strongly susceptible to N leaching. From the present study it could be concluded, that key factors for reducing N and P leaching from clay soils are late ploughing, avoidance of early incorporation of clover-grass leys in order to sow a winter cereal, the use of undersown crops and an even distribution of nutrients within the crop rotation. For the sandy soil, where measures like undersown crops and spring tillage were already integrated in the studied crop rotation, potato cultivation and application of farmyard manure were identified as the main sources of N losses to the drainage water
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6.
  • Neumann, Angelika, et al. (författare)
  • Losses of nitrogen and phosphorus via the drainage system from organic crop rotations with and without livestock on a clay soil in southwest Sweden
  • 2011
  • Ingår i: Organic Agriculture. - : Springer Science and Business Media LLC. - 1879-4238 .- 1879-4246. ; 1, s. 217-229
  • Tidskriftsartikel (refereegranskat)abstract
    • Leaching losses of N and P were examined in separately tile-drained field plots on a clay soil with two 6-year organic crop rotations (1998–2006). Two different farming systems (with dairy cows (+L) and without stock (−L)) were evaluated to identify parts of the crop rotations with the greatest risks of N and P leaching losses and to examine the scope for improvement. Although N and P leaching losses tended to be higher without livestock, the mean annual leaching loads from both systems were low and did not differ significantly (6.8 and 9.1 kg N ha−1 year−1 and 0.39 and 0.55 kg Pha−1 year−1 for +L and −L, respectively). For both systems, there were increased amounts of N and P in drainage water in the period following sowing of winter wheat after incorporation of clover–grass ley (CG). This could be attributed to the early date of CG incorporation, as late incorporation followed by bare fallow gave lower nutrient leaching. Drainage from bare fallow after a broad bean crop was identified as a critical part of the crop rotation for P leaching, with P losses possibly enhanced by macropore formation by the taproot of broad bean. The lowest leaching losses were observed during CG growth, demonstrating that CG had a buffering effect on leaching during heavy precipitation events. It was concluded that in organic farming on clay soils, countermeasures such as undersown CG and late incorporation of this CG can be effective in reducing N and P leaching losses
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7.
  • Neumann, Angelika, et al. (författare)
  • Nitrogen and phosphorus leaching losses from potatoes with different harvest times and following crops
  • 2012
  • Ingår i: Field Crops Research. - : Elsevier BV. - 0378-4290 .- 1872-6852. ; 133, s. 130-138
  • Tidskriftsartikel (refereegranskat)abstract
    • A 3-year field study (2007-2009) was conducted in separately tile-drained plots on a sandy soil in southwest Sweden to determine nitrogen (N) and phosphorus (P) leaching losses from potatoes to the drainage system. Different types of potatoes were grown and harvested at different times followed by different crops in order to identify the potato type/following crop system with the lowest risk of N and P leaching losses. Accumulated annual amounts of N and P lost to drainage between May (potato planting) and the following April varied between 13 and 72 kg N ha(-1) and 0.04 and 0.24 kg P ha(-1) depending on treatment and year. P leaching losses from this particular soil were low and differences between potato types not distinct, but there were significant differences between years. Abnormally high precipitation in summer 2007 led to significantly higher P leaching losses than in other years. N leaching losses were also higher in 2007, but differences between potato types were found in all years. Despite the high mineral soil nitrogen content (N-min) after harvest in June, early potatoes (EP) with oilseed radish (oil) as catch crop showed the lowest N leaching losses of all potatoes. Potatoes harvested in August (table potato; TP) and September/October (late potato; LP) followed by triticale (tri) sown in October showed the highest leaching losses. Thus under current climate conditions in Sweden, oilseed radish after EP is a suitable catch crop for N, while triticale sown in October is ineffective in preventing N leaching after potatoes. The late harvest of starch potatoes (SP) did not allow establishment of a following crop. However, SP showed lower N leaching losses than TP + tri and LP + tri due to lower residual N-min in deeper soil layers, low temperatures after harvest decreasing soil N mineralisation and higher C:N ratio of the potato haulm leading to lower N mineralisation potential. As a mean of all years, N leaching losses during and after EP + oil and SP were similar to those from the reference crop spring barley (SB), whereas TP + tri and LP + tri require countermeasures against N leaching. (C) 2012 Elsevier B.V. All rights reserved.
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8.
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9.
  • Stjernman Forsberg, Lovisa, et al. (författare)
  • Växtnäringsförluster från åkermark 2010/2011 : Årsredovisning för miljöövervakningsprogrammet Observationsfält på åkermark
  • 2012
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Inom programmet Observationsfält på åkermark undersöks avrinning, växtnäringsutlakning och odlingsåtgärder på ett antal fält (12 st) som ingår i lantbrukares normala drift. Programmet ingår i den nationella miljöövervakningen på Jordbruksmark med Naturvårdsverket som ansvarig myndighet, och med SLU som ansvarig utförare. I denna rapport redovisas resultat för det agrohydrologiska året 2010/2011.Rapporten redovisar bl.a. flödesvägda årsmedelhalter, transporter och avrinning för varje fält, medan klimatet redovisas översiktligt för olika delar av Sverige.Under 2010/2011 föll det mycket regn under sommarmånaderna och den totala årsnederbörden var större än den normala vid flera av de nederbördsstationer som ligger nära något av observationsfälten (tabell 4). På hälften av fälten avspeglade sig den rikliga årsnederbörden i en riklig årsavrinning, men på övriga fält var årsavrinningen mindre än normalt. På de flesta fält var januari en månad med ovanligt stor avrinning, detta i samband med plusgrader och snösmältning efter en period med kyla och snö under senhösten.De flödesvägda årsmedelhalterna av totalkväve var lägre än flerårsmedel på de flesta fält. I flera fall kan vinterbevuxen mark ha bidragit till de låga halterna. På vissa fält blev dock årstransporten av kväve större än flerårsmedel, trots låga kvävehalter. Detta till följd av riklig årsavrinning. Årsmedelhalterna av totalfosfor i dräneringsvattnet var låga eller oförändrade på samtliga fält. Endast ytvattnet från fält 14AC (Västerbotten) hade en årsmedelhalt av totalfosfor som var högre än flerårsmedel.Även årstransporterna av totalfosfor låg i de flesta fall nära eller under flerårsmedelvärdena.Information och data från undersökningen kan hämtas via www.slu.se/mark/dv.
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