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.
2025
Authors
Junbin Zhao Simon Weldon Alexandra Barthelmes Erin Swails Kristell Hergoualc’h Ülo Mander Chunjing Qiu John Connolly Whendee L. Silver David I. CampbellAbstract
No abstract has been registered
Abstract
Climatic drought and changes in precipitation patterns are key features of the ongoing and predicted climatic changes in northern latitudes such as the boreal forest of Norway. Recent droughts highlight on the possible difficult future of spruce forests in southern Norway. To better understand and monitor these forests under a more extreme climate, it is crucial to gain a better understanding of the water relations of spruce trees across forest stands. Sap flow sensors are typically used for directly measuring the water demands for transpiration in individual trees. There are however limitations to their use in examining the hydraulic and physiological responses to extreme water supply variability: i) manufactured high-resolution sensors such as those following the Heat Ratio Method (HRM) or Heat Field Deformation (HFD) are expensive, limiting their deployment to a few trees in a stand, and ii) the sap flow sensors only measure the movement of water within the active sapwood, not accessing other physiological mechanisms and responses (radial growth, water storage) associated with stress response. Point dendrometers have become increasingly used, monitoring sub-daily stem size fluctuations resulting from both seasonal patterns of radial growth increment and the dynamics of plant tissue water balance. Manufactured point dendrometers are much cheaper to buy and easier to install and maintain than manufactured sap flow sensors. They can therefore be much more extensively deployed across forest stands. We aimed to analyse the relationship between sub-daily stem diameter changes and sap flow using point dendrometers and HRM sap flow sensors installed in a Norway spruce forest located 50 km north of Oslo, Norway. We linked these relationships with individual tree physical attributes, meteorology and soil climate over two growing seasons in 2022 and 2023. Our goal was to assess whether a predictive model of sap flow could be built from measured diameter changes, tree properties and climate, to ultimately reduce the uncertainty of stand level transpiration estimation at the daily resolution across entire forest stands.
Abstract
In terrestrial ecosystems, forest stands are the primary drivers of atmospheric moisture and local climate regulation, making the quantification of transpiration (T) at the stand level both highly relevant and scientifically important. Stand-level T quantification complements evapotranspiration monitoring by eddy-covariance systems, providing valuable insight into the water use efficiency of forested ecosystems in addition to serving as important inputs for the calibration and validation of global transpiration monitoring products based on satellite observations. Stand level T estimates are typically obtained by scaling up individual tree estimates of water movement within the xylem – or sap flow. This movement affects the radius of a tree stem, whose fluctuations over the diel cycle provide pertinent information about tree water relations which can be readily detected by point (or precision) dendrometers. While sap flow measurements have greatly advanced our understanding of water consumption (T) at the level of individual trees, deploying conventional sap flow monitoring equipment to quantify T at the level of entire forested stands (or ecosystems) can quickly become costly since sap flow measurements from many trees are required to reduce the uncertainty of the upscaling. Using a boreal old-growth Norway spruce stand at an ICOS site in Southern Norway as a case study, we assess the potential of augmenting conventional sap flow monitoring systems with sap flow modeling informed by point dendrometer measurements to reduce the uncertainty of stand level T estimation at the daily resolution. We test the hypothesis that the uncertainty reduction afforded by a boosted tree sample size more than offsets the propagation of uncertainty originating from the point dendrometer-based sap flow estimates.
Authors
H. Heinemann F. Durand-Maniclas F. Seidel F. Ciulla Teresa Gómez de la Bárcena M. Camenzind S. Corrado Z. Csűrös Zs. Czakó D. Eylenbosch Andrea Ficke C. Flamm J.M. Herrera V. Horáková A. Hund F. Lüddeke F. Platz B. Poós Daniel Rasse M. da Silva-Lopes M. Toleikiene A. Veršulienė M. Visse-Mansiaux K. Yu J. Hirte A. DonAbstract
Ensuring food security through sustainable practices while reducing greenhouse gas emissions are key challenges in modern agriculture. Utilising genetic variability within a crop species to identify varieties with higher root biomass carbon (C) could help address these challenges. It is thus crucial to quantify and understand intra-specific above- and belowground performance under varying environmental conditions. The study objectives were to: (a) quantify root biomass and depth distribution in different winter wheat varieties under various pedoclimatic conditions, (b) investigate the influence of variety and pedoclimatic conditions on the relationship between above- and belowground biomass production, and (c) assess whether optimised winter wheat variety selection can lead to both greater root biomass C and yield, boosting C accrual. Root biomass, root distribution to 1 m soil depth and root-to-shoot ratios were assessed in 10 different winter wheat varieties grown at 11 experimental sites covering a European climatic gradient from Spain to Norway. Median root biomass down to 1 m depth was 1.4 ± 0.7 Mg ha−1. The primary explanatory factor was site, accounting for 60% of the variation in root biomass production, while the genetic diversity between wheat varieties explained 9.5%. Precipitation had a significantly negative effect on total root biomass, especially in subsoil. Significant differences were also observed between varieties in root-to-shoot ratios and grain yield. The difference between the variety with the lowest root biomass and the one with the highest across sites was on average 0.9 Mg ha−1 which is an increase of 45%. Pedoclimatic conditions had a greater influence than variety, and determined the relationship's direction between root biomass and grain yield. A site-specific approach is, therefore, needed to realise the full potential for increased root biomass and yield offered by optimised variety selection. Summary The variability in root biomass among 10 winter wheat varieties was quantified in field trials. Root biomass differs significantly between varieties, but is mainly driven by site conditions. Root-to-shoot ratios decreased with increasing precipitation. Root biomass was 45% higher in the best performing variety compared to the worst performing one.
Authors
Sonja G. Keel Alice Budai Lars Elsgaard Brieuc Hardy Florent Levavasseur Liang Zhi Claudio Mondini César Plaza Jens LeifeldAbstract
The potential for soil carbon (C) sequestration strongly depends on the availability of plant biomass inputs, making its efficient use critical for designing net zero strategies. Here, we compared different biomass processing pathways and quantified the long-term effect of the resulting exogenous organic materials (EOMs) to that of direct plant residue input on soil organic carbon (SOC) storage. We estimated C losses during feed digestion of plant material, storage of manure, composting and anaerobic digestion of plant material and manure, and pyrolysis of plant material, using values reported in the literature. We then applied an extended version of the widely used SOC model RothC with newly developed parameters to quantify the SOC storage efficiency, that is, accounting for both processing losses off-site and decomposition losses of the different EOMs in the soil. Based on simulations for a 39-year long cropland trial in Switzerland, we found that the SOC storage efficiency is higher for plant material directly added to the soil (16%) compared to digestate and manure (3% and 5%, respectively). For compost, the effect was less clear (2% ̶ 18%; mean: 10%) due to a high uncertainty in C-losses during composting. In the case of biochar, 43% of the initial plant C remained in the soil, due to its high intrinsic stability despite C-losses of 54% during pyrolysis. To provide robust recommendations for optimal biomass use, it is essential to consider additional factors such as nutrient availability of EOMs, environmental impacts of soil application, and life cycle assessments for the entire production processes.
Abstract
• Conventional forest operations can exert significant impacts on the hydrology and water quality of downstream aquatic environments. • Few research results have been published on the impacts of continuous cover forestry (CCF) on water quality. • CCF could be useful for reducing nutrient, carbon, and suspended solid exports in waterways. • CCF may be a better alternative to rotation forestry (RF) on mineral soils and drained peatlands. • Further research is needed on the many processes controlling nutrient and carbon exports in CCF and RF.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Shuang Yin Xinli Chen Gabin Piton César Terrer Zhenghu Zhou Gerlinde B. De Deyn Isabelle Bertrand Daniel Rasse Ji Chen Jose Antonio Navarro-Cano Diego AbalosAbstract
Increasing species diversity in agroecosystems appears as a promising venue to restore or increase soil organic carbon (SOC). It has been hypothesized that this effect is largely driven by the greater variation of root systems in plant mixtures, which may promote complementarity. However, the magnitude of this synergistic effect and the root traits driving it are uncertain. The objective of this study is to determine which root trait composition optimizes plant mixture effects on SOC. To do so, we combined a global meta-analysis of 407 paired SOC content observations under mixed species vs. monocultures across grasslands and croplands, and root traits extracted from the GRooT database. The results show that high root mycorrhizal colonization and root tissue density for the species in the mixture have higher positive effects on SOC content. Our analysis also indicates that combining species with high similarity for these traits represents a preferable trait combination to increase SOC with plant mixtures, challenging the current paradigm around plant trait complementarity effects. We observed that the positive response of SOC content to species mixtures was tightly associated with increased root biomass and soil microbial biomass carbon, indicating an important contribution of belowground and microbial residuals to SOC. Additionally, SOC enhancements by plant species mixtures were more likely to be realized in regions with high precipitation, clay-rich soils, and when legumes are present. Our meta-analysis lays out a root-trait framework to enhance SOC with plant mixtures, which can serve as a guide for species and variety selection for field experiments and on-farm applications.
Abstract
Quantifying the impact of biochar on carbon persistence across soil textures is complex, owing to the variability in soil conditions. Using artificial soils with precise textural and mineral compositions, we can disentangle the effects of biochar from the effects of soil particle size. We can show that biochar application significantly reduces the early-stage carbon mineralization rates of plant residues in various soil textures (from 5 % to 41 % clay) but more significantly in sandy soils. Clay and silt particles alone also reduce C mineralization, but the magnitude of the changes is negligible compared to the impact of biochar. This finding suggests that biochar can compensate for the lack of clay in promoting C persistence in soil systems. This short report contributes substantially to understanding soil texture and biochar application interactions.