Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Abstract
The occurrence of freeze–thaw cycles modifies water infiltration processes and surface runoff generation. Related processes are complex and are not yet fully investigated at field scale. While local weather conditions and soil management practices are the most important factors in both runoff generation and surface erosion processes, local terrain heterogeneities may significantly influence soil erosion processes in catchments with undulating terrain. This paper presents a field-based investigation of spatial and temporal heterogeneities in subsurface soil moisture and soil temperature associated with freezing, thawing, and snowmelt infiltration. The field setup consists of a combination of traditional point measurements performed with frequency domain reflectometry (FDR) and electrical resistivity tomography (ERT). The transect was approximately 70 m long and spanned an entire depression with a north-facing slope (average slope of 11.5%) and a south-facing slope (average slope of 9.7%). The whole depression was entirely covered with stubble. Observed resistivity patterns correspond well to the measured soil moisture patterns. During the observation period, the north facing slope froze earlier and deeper compared with the south facing slope. Freeze–thaw cycles were less pronounced in the north-facing slope than in the south-facing slope. There were also differences in soil temperature and soil moisture patterns between lower and upper parts of the monitored depression. These indicate that initiation and development of runoff related processes, and consequently soil erosion, in regions with freeze–thaw cycles may differ significantly depending on local terrain characteristics. Consequently, it indicates that spatial terrain heterogeneities, especially slope aspects, may be important when studying soil erosion processes, water flow and nutrient leaching in lowlands where patchy snowpacks and dynamic freeze–thaw cycles are predominating.
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Authors
Trine Eggen Heidi Amlund Robert Barneveld Aksel Bernhoft Gunnar Sundstøl Eriksen Belinda Eline Flem Torsten Källqvist Line Emilie Tvedt Sverdrup Stefan Trapp Anne Falk Øgaard Christiane Kruse Fæste Erik Jan Robert Lock Einar Ringø Håvard Steinshamn Robin Ørnsrud Åshild KrogdahlAbstract
Key words: VKM, risk assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Environment Agency, potential toxic elements (PTEs), fertiliser, soil improver, fertiliser products, growing media, circular economy, circulation of organic fertilisers, arsenic (As), cadmium (Cd), chromium Cr(tot) (Cr(III) and Cr(VI)), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni), zinc (Zn). Background and purpose of the report The potentially toxic elements (PTE) arsenic (As), cadmium (Cd), chromium Cr(tot) (Cr(III) and Cr(VI)), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn) occur as ingredients or contaminants in many fertilisers, soil improvers, engineered soil and growing media. Application of these fertiliser products might represent a risk towards the environment, farm animals and humans, particularly when applied annually over several years. The present risk assessment evaluates the application of selected fertilisers according to certain scenarios for representative Norwegian agricultural areas, from Troms in the North to Ås in Southeastern and Time in Southwestern Norway, with different soil properties, precipitation and PTE concentration in present agricultural soil. There is an increasing trend to produce locally (e.g. in urban farming) and home-grown vegetables that are cultivated in engineered soil and growth media. The maximum levels (MLs) set for PTEs in different organic fertilisers, engineered soil and growing media for use in urban farming, home growing and the cultivation of vegetables and garden fruits, and a set of MLs also for application in agricultural cultivation of crops, have been evaluated. Environmental fate processes and the transfer of PTEs have been modelled and the environmental risks for terrestrial and aquatic organisms, including from secondary poisoning have been estimated. Potential risks to humans and farmed animals by increased exposure to PTEs from, respectively, agriculturally produced crops, vegetables cultivated at home and urban farming or forage and grazing have been evaluated. The recycling of nutrients is urgently needed to achieve circular economy, but the derived sustainable products have to be safe, which requires the introduction of and adherence to science-based maximum levels of unwanted substances (e.g. pollutants). This assessment evaluates consequences of the application of different fertiliser products: mineral P fertilisers, manure from cattle, pig, poultry and horse, fish sludge, digestates and sewage sludge - in order to identify PTE sources with potential environmental, animal and human health risks, and to evaluate the appropriateness of the current MLs regarding different applications of organic-based fertilisers, engineered soil and growing media at present, and in a 100-year perspective. Approach and methods applied The approach for environmental and health risk assessments builds on previous work performed for hazardous substances in soil (e.g. VKM 2019, VKM 2014, VKM, 2009, Six and Smolders, 2014). Concentrations of PTEs in soil over time were calculated using a mass balance model, which considers the input by atmospheric deposition, use of fertilisers and soil improvers, as well as loss by leaching, run-off and plant uptake. The resulting first-order differential equation was solved analytically and implemented into Excel®. Run-off and loss by leaching were estimated from data on precipitation, infiltrating fraction and run-off fraction of the water under consideration of the distribution coefficient Kd for the concentration ratio of bulk soil-to-water. This Kd value takes aging sufficiently into account and is thus more realistic than those derived from batch tests. The Kd was estimated separately for each region using established regression equations, with soil pH, organic matter content and clay content as predictors. ...........
Abstract
No abstract has been registered
Authors
Yong Q. Tian Qian Yu Hunter J. Carrick Brian L. Becker Remegio Confesor Mark Francek Olivia C. AndersonAbstract
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Authors
Haley Kujawa Margaret Kalcic Jay Martin Anna Apostel Jeffrey Kast Asmita Murumkar Grey Evenson Noel Aloysius Richard Becker Chelsie Boles Remegio Confesor Awoke Dagnew Tian Guo Rebecca Logsdon Muenich Todd Redder Yu-Chen Wang Donald ScaviaAbstract
This study investigates the combined impacts of climate change and agricultural conservation on the magnitude and uncertainty of nutrient loadings in the Maumee River Watershed, the second-largest watershed of the Laurentian Great Lakes. Two scenarios — baseline agricultural management and increased agricultural conservation — were assessed using an ensemble of five Soil and Water Assessment Tools driven by six climate models. The increased conservation scenario included raising conservation adoption rates from a baseline of existing conservation practices to feasible rates in the near future based on farmer surveys. This increased adoption of winter cover crops on 6%–10% to 60% of cultivated cropland; subsurface placement of phosphorus fertilizers on 35%–60% to 68% of cultivated cropland; and buffer strips intercepting runoff from 29%–34% to 50% of cultivated cropland. Increased conservation resulted in statistically significant (p ≤ 0.05) reductions in annual loads of total phosphorus (41%), dissolved reactive phosphorus (18%), and total nitrogen (14%) under the highest emission climate scenario (RCP 8.5). While nutrient loads decreased with increased conservation relative to baseline management for all watershed models, different conclusions on the true effectiveness of conservation under climate change may be drawn if only one watershed model was used.
Authors
Jian LiuAbstract
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Authors
Jian LiuAbstract
No abstract has been registered
Abstract
Aims Root traits associated with resource foraging, including fine-root branching intensity, root hair, and mycorrhiza, may change in soils that vary in rock fragment content (RFC), while how these traits covary at the level of individual root branching order is largely unknown. Methods We subjected two xerophytic species, Artemisia vestita (subshrub) and Bauhinia brachycarpa (shrub), to increasing RFC gradients (0%, 25%, 50%, and 75%, v v− 1) in an arid environment and measured fine-root traits related to resource foraging. Results Root hair density and mycorrhizal colonization of both species decreased with increasing root order, but increased in third- or fourth-order roots at high RFCs (50% or 75%) compared to low RFCs. The two species tend to produce more root hairs than mycorrhizas under the high RFCs. For both species, root hair density and mycorrhizal colonization intensity were negatively correlated with root length and root diameter across root order and RFCs. Rockiness reduced root branching intensity in both species comparing with rock-free soil. At the same level of RFC, A. vestita had thicker roots and lower branching intensity than B. brachycarpa and tended to produce more root hairs. Conclusion Our results suggest the high RFC soil conditions stimulated greater foraging functions in higher root orders. We found evidence for a greater investment in root hairs and mycorrhizal symbioses as opposed to building an extensive root system in rocky soils. The two species studied, A. vestita and B. brachycarpa, took different approaches to foraging in the rocky soil through distinctive trait syndromes of fine-root components.