| 1. |
- Ericsson, Tom, et al.
(författare)
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Demand-driven fertilization. Part I: Nitrogen productivity in four high-maintenance turf grass species
- 2012
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Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 62, s. 113-121
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Tidskriftsartikel (refereegranskat)abstract
- The effect of four nitrogen (N) availabilities on growth, leaf N concentration, N productivity (dry matter production per unit time and unit N taken up), shoot: root ratio and carbohydrate storage was studied in velvet bentgrass (Agrostis canina 'Legendary'), creeping bentgrass (A. stolonifera 'Independence'), slender creeping red fescue (Festuca rubra ssp. trichophylla 'Cezanne') and chewings fescue (F. rubra ssp. commutata 'Center'). In growth chamber experiments, plants were grown for 3 weeks in sand with 12.5, 25, 50 or 200 mg N L-1 in the irrigation water and at two mowing intensities, cut at 5 mm twice per week or uncut. It proved possible to control important turf grass traits such as shoot growth rate, shoot: root ratio, leaf morphology and carbohydrate storage through leaf N concentration. The relationship between leaf N concentration and aboveground growth was linear for both cut and uncut turf. The relative N demand of the studied species, based on their N productivity, was 1: 0.67: 0.67: 0.37 for creeping bentgrass, velvet bentgrass, chewings fescue and slender creeping red fescue, respectively. Clipping significantly reduced N productivity, and hence turf N demand. The lowest possible leaf N concentration without adverse effects on plant health and appearance was between 3.1 and 3.5% of dry matter (DM) in both bentgrasses and fescues. This value can be used as a target in minimizing fertilizer usage and N leaching losses. In conclusion, fertilization based on the influence of leaf N concentration on growth-related processes offers possibilities to control growth in a predictable and desirable manner under varying climate and growth conditions. This could provide more environmentally friendly and economic fertilization regimes and also better playing quality.
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| 2. |
- Ericsson, Tom, et al.
(författare)
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Demand-driven fertilization. Part II: Influence of demand-driven fertilization on shoot nitrogen concentration, growth rate, fructan storage and playing quality of golf turf
- 2012
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Ingår i: Acta Agriculturae Scandinavica, Section B - Soil and Plant Science. - : Informa UK Limited. - 0906-4710 .- 1651-1913. ; 62, s. 139-149
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Tidskriftsartikel (refereegranskat)abstract
- The ability of demand-driven fertilization, based on the growth potential provided by solar radiation and temperature, to regulate golf turf characteristics such as growth rate, leaf nitrogen (N) concentration, carbohydrate storage and playing quality was investigated in a 2-year field experiment at Landvik, Norway. Three N regimes (100, 60 and 40% of the estimated N requirement for maximum growth) were applied on a sand-based green with a turf cover consisting of creeping bentgrass, colonial bentgrass, velvet bentgrass, slender creeping red fescue or chewings fescue. In the 100% treatment, this corresponded to 3 (creeping bentgrass), 2.1 (colonial and velvet bentgrass) and 1.5 (chewings and slender creeping red fescue) kg N 100 m(-2) yr(-1). The weekly liquid fertilizer dose basically followed the potential growth curve provided by solar radiation and temperature from early April to late October. The turf was exposed to artificial wear and daily maintenance followed conventional standards. Growth, leaf N concentration, carbohydrate storage in clippings, green appearance and playing quality were determined once per month. The results indicated that solar radiation and temperature can successfully be used as driving variables when quantifying turf fertilizer requirements from early spring to late autumn. The desired leaf N concentration, i.e. growth rate, and the resulting effects on fructan content and playing quality can be achieved by raising or lowering the seasonal fertilizer curve. A leaf N level of 3.1-3.5% was indicated as the lower limit for producing healthy-looking turf with high playing quality.
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| 3. |
- Neumann, Angelika, et al.
(författare)
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Identification of key factors for reducing N and P leaching from organic crop rotations
- 2011
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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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| 4. |
- Neumann, Angelika, et al.
(författare)
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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
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Ingår i: Organic Agriculture. - : Springer Science and Business Media LLC. - 1879-4238 .- 1879-4246. ; 1, s. 217-229
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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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| 5. |
- Neumann, Angelika, et al.
(författare)
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Nitrogen and phosphorus leaching losses from potatoes with different harvest times and following crops
- 2012
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Ingår i: Field Crops Research. - : Elsevier BV. - 0378-4290 .- 1872-6852. ; 133, s. 130-138
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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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| 6. |
- Wylensek, David, et al.
(författare)
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A collection of bacterial isolates from the pig intestine reveals functional and taxonomic diversity
- 2020
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Our knowledge about the gut microbiota of pigs is still scarce, despite the importance of these animals for biomedical research and agriculture. Here, we present a collection of cultured bacteria from the pig gut, including 110 species across 40 families and nine phyla. We provide taxonomic descriptions for 22 novel species and 16 genera. Meta-analysis of 16S rRNA amplicon sequence data and metagenome-assembled genomes reveal prevalent and pig-specific species within Lactobacillus, Streptococcus, Clostridium, Desulfovibrio, Enterococcus, Fusobacterium, and several new genera described in this study. Potentially interesting functions discovered in these organisms include a fucosyltransferase encoded in the genome of the novel species Clostridium porci, and prevalent gene clusters for biosynthesis of sactipeptide-like peptides. Many strains deconjugate primary bile acids in in vitro assays, and a Clostridium scindens strain produces secondary bile acids via dehydroxylation. In addition, cells of the novel species Bullifex porci are coccoidal or spherical under the culture conditions tested, in contrast with the usual helical shape of other members of the family Spirochaetaceae. The strain collection, called 'Pig intestinal bacterial collection' (PiBAC), is publicly available at www.dsmz.de/pibac and opens new avenues for functional studies of the pig gut microbiota. The authors present a public collection of 117 bacterial isolates from the pig gut, including the description of 38 novel taxa. Interesting functions discovered in these organisms include a new fucosyltransferease and sactipeptide-like molecules encoded by biosynthetic gene clusters.
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