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- Carlsson, Georg, et al.
(författare)
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Perennial species mixtures for multifunctional production of biomass on marginal land
- 2017
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Ingår i: GCB Bioenergy. - : Wiley. - 1757-1693 .- 1757-1707. ; 9:1, s. 191-201
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional agriculture provides noncommodity functions and services along with food, feed and bioenergy feedstocks, for example by preserving or promoting biodiversity, improving soil fertility, mitigating climate change and environmental degradation, and contributing to the socio-economic viability of rural areas. Producing biomass for bioenergy from low-input perennial species mixtures on marginal land has the potential to support biodiversity and soil carbon sequestration in synergy with greenhouse gas mitigation. We compared biomass production in species-rich mixtures of perennial grasses, legumes and forbs with pure-stand grasses and relatively species-poor mixtures under different nitrogen fertilization regimes. Field experiments were performed on different types of marginal land, that is agricultural field margins and land with poor soil fertility, at four sites in southernmost and western Sweden. Biomass production was measured for three years in perennial grasses grown as pure stands, in legume-grass mixtures, and legume-grass-forb mixtures across a species richness gradient. In unfertilized species-rich mixtures, average biomass yields per experimental site and year were in the range from 3 to 9 metric ton DM ha−1 yr−1. While the most productive pure-stand grasses fertilized with 60–120 kg N ha−1 yr−1 often produced higher biomass yields than unfertilized mixtures, these differences were generally smaller than the variations between years and sites. Calculations of climate impact using the harvested biomass for conversion to biogas as vehicle fuel showed that the average greenhouse gas emissions per energy unit were about 50% lower in unfertilized systems than in treatments fertilized with 100–120 kg N ha−1 yr−1. Our findings thereby show that unfertilized species-rich perennial plant mixtures on marginal land provide resource-efficient biomass production and contribute to the mitigation of climate change. Perennial species mixtures managed with low inputs thus promote synergies between productivity and biodiversity in the perspective of climate-smart and multifunctional biomass production.
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| 2. |
- Dimitrova Mårtensson, Linda-Maria, et al.
(författare)
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Water use efficiency and shoot biomass production under water limitation is negatively correlated to the discrimination against 13C in the C3 grasses Dactylis glomerata, Festuca arundinacea and Phalaris arundinacea
- 2017
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Ingår i: Plant Physiology and Biochemistry. - : Elsevier BV. - 0981-9428 .- 1873-2690. ; 113, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Climate change impacts rainfall patterns which may lead to drought stress in rain-fed agricultural systems. Crops with higher drought tolerance are required on marginal land with low precipitation or on soils with low water retention used for biomass production. It is essential to obtain plant breeding tools, which can identify genotypes with improved drought tolerance and water use efficiency (WOE). In C-3 plant species, the variation in discrimination against C-13(Delta,13C) during photosynthesis has been shown to be a potential indicator for WOE, where discrimination against C-13 and WUE were negatively correlated. The aim of this study was to determine the variation in the discrimination against C-13 between species and cultivars of three perennial C-3 grasses (Dactylis glomerate (cocksfoot), Festuca arundinacea (tall fescue) and Phalaris arundinacea (reed canary grass)) and test the relationships between discrimination against C-13, season-long water use WUEB, shoot and root biomass production in plants grown under well-watered and water-limited conditions. The grasses were grown in the greenhouse and exposed to two irrigation regimes, which corresponded to 25% and 60% water holding capacity, respectively. We found negative relationships between discrimination against C-13 and WUEB and between discrimination against C-13 and shoot biomass production, under both the well-watered and water-limited growth conditions (p < 0.001). Discrimination against C-13 decreased in response to water limitation (p < 0.001). We found interspecific differences in the discrimination against C-13, WUEB, and shoot biomass production, where the cocksfoot cultivars showed lowest and the reed canary grass cultivars highest values of discrimination against C-13. Cocksfoot cultivars also showed highest WUEB, shoot biomass production and potential tolerance to water limitation. We conclude that discrimination against C-13 appears to be a useful indicator, when selecting C-3 grass crops for biomass production under drought conditions. (C) 2017 Elsevier Masson SAS. All rights reserved.
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| 3. |
- Eckersten, Henrik, et al.
(författare)
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Nitrogen leaching and soil organic carbon sequestration of a Barley crop with improved N use efficiency : A regional case study
- 2017
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Ingår i: Acta Agriculturae Scandinavica - Section B. - : Taylor and Francis Ltd.. - 0906-4710 .- 1651-1913. ; 67:7, s. 615-627
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Tidskriftsartikel (refereegranskat)abstract
- The potential of modified spring barley crops with improved nitrogen (N) use efficiency to reduce nitrogen (N) leaching and to increase soil organic carbon (SOC) storage was assessed at the regional scale. This was done using simulation model applications designed for reporting according to the Helcom (Helsinki Commission) and Kyoto protocols. Using model simulations based on modified crops N dynamics and SOC were assessed for three agro-ecological regions (latitudes ranging 55°20′–60°40′ N) in Sweden over a 20-year period. The modified N use properties of spring barley were implemented in the SOILNDB model (simulating soil C, N, water and heat, and plant N dynamics) by changing the parameters for root N uptake efficiency and plant N demand within a range given by previous model applications to different crops. A doubling of the daily N uptake efficiency and increased N demand (by ca 30%) reduced N leaching by 24%–31%, increased plant N content by 9%–12%, depending on region. The effects of the modified crop on SOC was simulated with the ICBM model, resulting in an increased SOC content (0–25 cm depth) by 57–79 kg C ha−1 y−1. The results suggest that a modified crop might reduce N leaching from spring barley area, in a range similar to the targets of relevant environmental protection directives, a result which held more in the northern than southern regions. The simulated SOC increase on a hectare basis was highest for the central region and least for the most northern region. For the total agricultural area the share of spring barley area was small and more crops would need to be modified to reach the emission reduction targets.
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