| 1. |
- Getahun, Gizachew Tarekegn, et al.
(författare)
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Short-term effects of loosening and incorporation of straw slurry into the upper subsoil on soil physical properties and crop yield
- 2018
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Ingår i: Soil and Tillage Research. - : Elsevier BV. - 0167-1987 .- 1879-3444. ; 184, s. 62-67
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Tidskriftsartikel (refereegranskat)abstract
- Subsoils that are compacted, nutrient-poor or low in soil organic matter (SOM) often limit crop growth and yield. Improvement of subsoil conditions by deep loosening is laborious and expensive and its positive effect may not last. This study investigated the effect of deep loosening and injection of slurry made from cereal straw (30 Mg dry mass ha(-1)) at 25-34 cm depth on soil properties and crop performance in a Swedish field experiment that started in autumn 2015 and monitored soil and crop properties during 2016. Loosening + straw incorporation into subsoil resulted in significantly higher soil organic carbon (SOC) content, potential plant-available water and porosity and lower bulk density (BD) in spring 2016 compared with the control. In autumn 2016, penetrometer resistance (PR) and BD were both significantly lower and SOC and porosity were significantly higher in the loosening + straw treatment compared with the control and loosening only (29-34 cm). Furthermore, BD was significantly lower in the loosening + straw treated subsoil than in the top soil layer of the control (0-10 cm). Observations indicated that more continuous pores were found in the loosening + straw treatment than in other treatments. Roots and soil faunas were found more frequently where straw was incorporated. Grain yield increased by 5.6% due to loosening + straw addition (P = 0.03) and by 4% due to loosening only (P = 0.06). These results indicate that loosening + straw input into upper subsoil had a positive short-term influence on soil physical properties, potential plant-available water and grain yield. Straw addition prolonged the positive effect of loosening.
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| 2. |
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| 3. |
- Prade, Thomas, et al.
(författare)
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Including a one-year grass ley increases soil organic carbon and decreases greenhouse gas emissions from cereal-dominated rotations – A Swedish farm case study
- 2017
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 164, s. 200-212
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Tidskriftsartikel (refereegranskat)abstract
- Increased soil organic carbon (SOC) content has been shown to increase soil fertility and carbon sequestration, but SOC changes are frequently neglected in life cycle assessment (LCA) studies of crop production. This study used a novel LCA application using simulated SOC changes to examine the greenhouse gas (GHG) impact of a combined food and energy crop production from a crop rotation perspective. On a case pig farm, introduction of one year of grass ley into a cereal-dominated crop rotation was simulated. The grass and pig manure were used for biogas production and the digestion residues were used as fertiliser on the farm. This crop rotation shift increased the SOC stocks by an estimated 27 and 49% after 50 years and at steady state, respectively. The estimated corresponding net wheat yield increase due to higher SOC was 8–16% and 16–32%, respectively, indicating that initial loss of low-yield oat production can be partly counterbalanced. Net SOC increase (corresponding to 2 t CO2-eq ha−1 a−1) was the single most important variable affecting the GHG balance. When biogas replaced fossil fuels, GHG emissions of the combined energy-food crop rotation were approx. 3 t CO2-eq ha−1 a−1 lower than for the current food crop rotation. Sensitivity analyses led to variation of only 2–9% in the GHG balance. This study indicates that integrated food and energy crop production can improve SOC content and decrease GHG emissions from cropping systems. It also demonstrates the importance of including SOC changes in crop production-related LCA studies.
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| 4. |
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| 5. |
- Andrén, Olof, et al.
(författare)
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Agroecosystem research in Uppsala, Sweden and Naiman, China: Some observations 1987–2014
- 2016
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Ingår i: Sciences in Cold and Arid Regions. - 1674-3822. ; 8, s. 1-8
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Forskningsöversikt (refereegranskat)abstract
- The recent economic progress in China has stimulated scientific research in sandy lands in Inner Mongolia, where the Institute of Desert Research, Chinese Academy of Sciences (now CAREERI) has a leading position. Economic progress naturally creates financial resources for research, and also a dire need for solutions to emerging environmental problems following development, where wind-blown dust from Inner Mongolia adds to the severe particle air pollution in many Chinese cities. This paper presents selected results and observations made during Chinese-Swedish cooperation projects spanning 25 years. Results and experiences from sandy land research concerning climate, vegetation, root dynamics, soil carbon balances, etc. are briefly presented. The evolution of the Naiman Desertification Research Station, 520 km northeast of Beijing, from 1988 to 2013 is duly noted and commented. An overview of the ICBM soil carbon model concept follows and a few recommendations for future scientific advancement in Chinese arid lands are given.
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| 6. |
- Bolinder, Martin, et al.
(författare)
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Canadian farm-level soil carbon change assessment by merging the greenhouse gas model Holos with the Introductory Carbon Balance Model (ICBM)
- 2016
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Ingår i: Agricultural Systems. - : Elsevier BV. - 0308-521X .- 1873-2267. ; 143, s. 76-85
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Tidskriftsartikel (refereegranskat)abstract
- The farm-level model Holos, developed to explore mitigation options for greenhouse gas emissions (GHG) from Canadian farming systems, includes soil carbon change as a prominent component. Soil carbon was assumed to be constant, except where there was recent change in land use or management (e.g., conventional vs. reduced vs. no tillage). The factors associated with the changes were derived using CENTURY model simulations. To make Holos more responsive to farm management (e.g., crop rotation and residue management) and inter-annual climate variation, it was decided to replace the carbon change factors with the Introductory Carbon Balance Model (ICBM), a simple two carbon pool model driven by inputs from above- and belowground crop residues and manure. We showcase how the model will simulate the impact of crop rotation management decisions on soil carbon change, focussing on the choice of crop and crop residue retention, but considering also tillage and fertilization management. We argue that simulating carbon change at each field involved in the rotation is advantageous because it allowsto test the rotation resilience with respect to inter-annual climate variation as well as to validate the model outputs using measurements of scientific long-term field experiments. We propose to report the farm-level carbon change results ranging from annual to centennial time frames which would be in line with the reporting requirements in carbon credit programs, while giving the user the capability to project and test new crop rotation systems using long-term carbon change forecasts. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.
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| 7. |
- Bolinder, Martin, et al.
(författare)
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Fånggrödor och rötrester i ICBM
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Målsättningen med detta utvecklingsprojekt var att göra en förstudie om tillgänglig statistik för fånggrödor och rötrester. Data med tidsserier för fånggrödor som används i andra modelleringsprojekt på SLU kan anpassas relativt enkelt för att inkluderas i kolbalansmodellen ICBM på länsnivå. För rötrester finns det också potentiella källor med tidsserier, men de skulle kräva lite mer förbehandling innan de kan användas. Båda dataserierna sträcker sig så pass långt bak i tiden att de representerar ganska bra den tidpunkten från och med att dessa två faktorer blir relevanta att ha med i markkolsmodelleringen. Modellparametrar (utöver areal fånggrödor och mängd rötrester), som man skulle behöva justera rör framför allt allometriska funktioner för fånggrödor och humifieringskoefficienten för biogödsel.
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| 8. |
- Bolinder, Martin, et al.
(författare)
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Implementing a new version of ICBM in NIR
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the sector Land Use, Land-Use Change and Forestry (LULUCF, CRF sector 4) within the national greenhouse gas inventory (NIR), Sweden is applying a Tier 3 method for estimating the loss or gain of soil organic carbon (SOC) stocks for cropland on mineral soils to a depth of 0.25 m. The Introductory Carbon Balance Model (ICBM) is used for calculating stock change rates in eight agricultural production regions and results are aggregated to the national level. Calculations involves yearly agricultural census data and daily weather records, as well as results from a national soil-monitoring program (SMP) on soil carbon contents. Initially, only data from the first sampling of the national SMP were used for initializing ICBM. Since the first soil inventory, two additional samplings within the SMP have become available. Simultaneously, we have also gained more knowledge about SOC dynamics. In a development project last year, we were re-analyzing the complete records of data from the last two decades of the SMP confirming that SOC stocks are increasing, and we were starting to calibrate a new version of ICBM. The purpose of the project this year was to implement the new ICBM version in the NIR system.The results show that the new version of ICBM simulates increasing SOC stocks for the period 1990 to 2018, which is thereby more consistent with estimates from the national SMP data than results obtained using the previous ICBM version. The ICBM and SMP assessment methods of SOC stock changes are complementing each other, and both have their inherent limitations. Our analysis with both methodologies are still not fully completed. There remain some fine-tuning in the new ICBM version. Furthermore, we are continuously working on improving the interpretation regarding SOC stocks in the current database from the national SMP. Maintaining the latter and repeating the sampling at least once more would also substantially improve the value of this database.
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| 9. |
- Bolinder, Martin, et al.
(författare)
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Net primary productivity and below-ground crop residue inputs for root crops: Potato (Solanum tuberosum L.) and sugar beet (Beta vulgaris L.)
- 2015
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Ingår i: Canadian Journal of Soil Science. - 0008-4271. ; 95, s. 87-93
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Tidskriftsartikel (refereegranskat)abstract
- Root crops are significant in agro-ecosystems of temperate climates. However, the amounts of crop residues for these crop types are not well documented and they need to be accounted for in the modeling of soil organic carbon dynamics. Our objective was to review field measurements of root biomass left in the soil as crop residues at harvest for potato and sugar beet. We considered estimates for crop residue inputs as root biomass presented in the literature and some unpublished results. Our analysis showed that compared to, for example, cereals, the contribution of below-ground net primary productivity (NPP) to crop residues is at least two to three times lower for root crops. Indeed, the field measurements indicated that root biomass for topsoils only represents on average 25 to 30 g dry matter (DM) m(-2) yr(-1). Other estimates, albeit variable and region-specific, tended to be higher. We suggest relative plant DM allocation coefficients for agronomic yield (R-P), above-ground biomass (R-S) and root biomass (R-R) components, expressed as a proportion of total NPP. These coefficients, representative for temperate climates (0.739:0.236:0.025 for potato and 0.626:0.357:0.017 for sugar beet), should be useful in the modeling of agro-ecosystems that include root crops.
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| 10. |
- Bolinder, Martin, et al.
(författare)
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New calibration of the ICBM model & analysis of soil organic carbon concentration from Swedish soil monitoring programs
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We are using the Introductory Carbon Balance Model (ICBM) within the national inventory reporting (NIR) system for estimating changes in soil organic carbon (SOC) stocks in Swedish arable land for mineral soils. The first version of ICBM was developing from a long-term experiment (LTE) in Ultuna Sweden, with a time-series of data from 1956 to 1991. The model is initialized using data from a soil database and information from Swedish soil monitoring programs (SMPs). For that purpose, it specifically uses data from the first inventory of the Swedish Environmental Protection Agency (SEPA) SMP conducted in the early 1990s. Since the 1990s, the SEPA SMP has conducted two further inventories in a 10-year cycles, with the last inventory completed in 2017. In complement to this SEPA SMP, the Swedish Board of Agriculture (SJV) was completing a spatially more detailed SMP in 2011 and 2012. In an earlier study, when the third inventory of SEPA was still not fully completed, we showed that SOC concentrations are increasing in Swedish arable mineral soils during the past two decades. Simulations with the current version of ICBM are not reproducing this long-term increasing trend.The main purposes of this project were to (i) calibrate a second version of ICBM by incorporating new knowledge gained from LTEs, (ii) evaluate the trends in SOC concentrations with the complete inventories (I, II and III) of SEPA, (iii) compare results from SEPAs last inventory (III) with that of SJV SMP conducted at approximately the same time period. A Bayesian approach was selected for calibrating the second version of ICBM, using an updated time series of data from Ultuna ending in 2017, and by also including experimental data (1996-2017) from a new sister experiment at Lanna in southern Sweden. For adequately comparing the SEPA and SJV SMPs, we were correcting data from the SJV samples so that we could express all results for SOC concentrations on a basis equivalent to dry combustion. Our analysis on the complete SEPA inventories are generally confirming our previous assessment. However, a more detailed exploration using data only from inventories II and III having identical sampling coordinates, clearly indicates that the increases in SOC concentrations were less in the last decade than in the previous one. Furthermore, when comparing SOC concentrations at different spatial scales, the positive trend in SOC concentrations is much more obvious on the scale of Swedish agricultural production regions (eight regions). Indeed, at the scale of the twenty-one Swedish counties, there are few significant differences and the increasing trend is unclear for many of the counties. This is reflecting difficulties related to the density of sampling points in the SEPA SMP; each of them roughly represents 1500 ha of arable land. Besides, only two decades or even only one decade since SEPA was regarding inventory II as a restart of their SMP, remain a short time period in detecting changes in SOC and highlight the importance of maintaining continuous SMPs.We found the comparisons between the SJV and SEPA SMPs useful but further work is necessary to refine the linkage. The overall changes in parameter values related to SOC dynamics for the calibrated second version of ICBM, will give simulations towards higher SOC stocks, compared to the current version. The main parameter explaining this differences is the increased contribution of below ground (i.e., roots) annual C inputs to soil contributing to the formation of more stable SOC. The approach we used here also offers the advantage of making a multi-site calibration and we could in the future, further refine parameter values by including other Swedish LTEs. Additionally, it allows us to include an estimate for uncertainty in the predictions of SOC stocks, which we could also develop for inclusion in the NIR system.
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