Hopp til hovedinnholdet

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.

2023

Abstract

Constructed wetlands (CWs) are a widely recognised measure for reducing pollution loads and improving the quality of surface waters. The removal efficiency of CWs varies considerably depending on system type and design as well as residence time, hydraulic load, particles and nutrient loading rates. Therefore, there is a need to closely monitor the efficiency of existing measures, look at their efficiency in practice and be able to foresee potential implications for their efficiency in light of climate change and land management intensification. This study presents 18 years of data from a typical Norwegian small CW established in the Skuterud catchment. The main objective of this study was to look at the impact of hydraulic load, particles and nutrient loads (depending on climatic factors such as temperature and precipitation) on CW effectiveness. The results showed an average of 39 % and 22 % annual removal efficiency for sediment and phosphorus, respectively. It appears that good CW effectiveness coincides with a combination of high sediment or phosphorus loads to the CW and a stable runoff of low to moderate intensity. At the seasonal level, the highest sediment and phosphorus removal efficiency is observed in the summer seasons (47% for sediment and 29% for phosphorus), when the sediment and phosphorus loads and runoff are at their lowest, and the lowest in autumn (23% for sediment) and in winter (4% for phosphorus). The relationship between removal efficiency and loads to the CW is not that straightforward, as other seasonal differences, such as erosion patterns, vegetation development, also become important. The conclusion based on the results presented is that establishing CWs can be a good supplement to best management practice in erosion-prone catchments with sensitive recipients.

To document

Abstract

Quantifying the similarities and differences in atmospheric nitrogen (N) deposition between different ecosystems is important to develop effective measures to reduce air pollution and maintain biodiversity. Here we show that the constitution of N deposition differed significantly between a grassland and a desert ecosystem in Northwestern China. Flux of bulk (wet plus part of dry deposition) and dry (gaseous NH3 and NO2) deposition were continuously monitored from 2018 to 2020. The grassland and desert sites had similar amount of total N deposition, being 7.29 and 6.33 kg N ha−1 yr−1, respectively. However, N deposition at the grassland was dominated by the bulk deposition (4.44 kg N ha−1 yr−1, 61% of the total N deposition), whereas that at the desert was dominated by dry deposition (4.20 kg N ha−1 yr−1, 66% of total deposition). The desert had greater ambient concentrations of NH3 (3.66 μg N m−3) and NO2 (1.52 μg N m−3) than the grassland (2.73 μg NH3–N m−3 and 0.72 μg NO2–N m−3). The amount of reduced N deposition (NH4+ and NH3) was around 3 times of that of oxidized N deposition (NO3− and NO2) in both ecosystems. The N deposition rates in both ecosystems have exceeded the critical load for the fragile ecosystems (5–10 kg N ha−1 yr−1), highlighting the importance of reducing N emission sources that are related with anthropogenic disturbance.

To document

Abstract

Soil nutrient contents and stoichiometric ratios are determinants for soil biogeochemical cycling and functions. Variable rock fragment contents (RFC) may shape the soil nutrient status and availability in mountain ecosystems. We need to better understand how and why soil nutrients and stoichiometry shift across the RFC gradients. To investigate patterns of soil nutrient stoichiometry and underlying mechanisms in rocky soils, we conducted a field experiment involving four RFCs gradients (0%, 25%, 50% and 75%, V/V) and five vegetation treatments (four indigenous species, Artemisia vestita, Bauhinia brachycarpa, Cotinus szechuanensis and Sophora davidii, plus a non-planted treatment). Soil total carbon (C), total nitrogen (N), total phosphorus (P) and their molar ratios were measured. The contents of soil C, N and P, and C:N, C:P and N:P decreased with increasing RFC in all treatments, despite their trends were inconsistent in certain soil layers. The averages of soil N content significantly increased by 13.8% and 14.8% in C. szechuanensis and S. davidii, respectively. A. vestita and B. brachycarpa had higher soil C:N than C. szechuanensis and S. davidii. Soil nutrients and stoichiometry were positively related to soil water content (SWC) and soil capillary porosity, and negatively to bulk density and soil non-capillary porosity in all vegetation treatments, but varying relationships with biomass of plant components. These results demonstrated negative effect of RFC and discrepant effects of the plants on soil nutrients and stoichiometry. Soil structure, SWC and vegetation were the main drivers of variations in soil nutrient stoichiometry. We further concluded that soil nutrient stoichiometry in rocky soils is shaped by two influencing paths; effects of RFC on soil physical properties (SWC and soil structure) and effects of different vegetations. Our findings advance knowledge and mechanisms of soil nutrient stoichiometry in rocky soils and provide theoretical support for improving and restoring nutrient status in stony regions.

2022

To document

Abstract

The deliverable D2.3 of the OPTAIN project introduces a framework and scale specific guidelines for the parameterization of Natural/Small Water Retention Measures (NSWRM) in modelling approaches. More specifically, it provides a detailed translation of NSWRM into parameters and design approaches for the application in the SWAT+ (catchment scale) and SWAP (field-scale) models, which were selected as the main modelling tools in the OPTAIN project. This document can also be considered as an extension of the well-known Conservation Practice Modelling Guide for SWAT and APEX (Waidler et al., 2011), which is frequently used by the SWAT modelling community for testing the effectiveness of conservation practices. However, besides of conservation practices, the report focuses mainly on NSWRMs, and how they can be implemented in SWAT+, the new and restructured version of SWAT. Analogously, the NSWRM parameters are also described for the SWAP model, which is addressing the field-scale. Compared to previous NSWRM modelling approaches, this methodology enables the setting of NSWRM parameters in the two selected models to improve the description of the related hydrological and hydrochemical processes.

Abstract

This report introduces a framework and scale specific guidelines for the parameterization of Natural/Small Water Retention Measures (NSWRM) in modelling approaches. More specifically, it provides a detailed translation of NSWRM into parameters and design approaches for the application in the SWAT+ (catchment scale) and SWAP (field-scale) models, which were selected as the main modelling tools in the OPTAIN project. This document can also be considered as an extension of the well-known Conservation Practice Modelling Guide for SWAT and APEX (Waidler et al., 2011), which is frequently used by the SWAT modelling community for testing the effectiveness of conservation practices. However, besides of conservation practices, the report focuses mainly on NSWRMs, and how they can be implemented in SWAT+, the new and restructured version of SWAT. Analogously, the NSWRM parameters are also described for the SWAP model, which is addressing the field-scale. Compared to previous NSWRM modelling approaches, this methodology enables the setting of NSWRM parameters in the two selected models to improve the description of the related hydrological and hydrochemical processes.

To document

Abstract

How can agroecological research methods effectively engage smallholder farmers, who provide over half of the world’s food supply, and whose farm management activities have significant impacts on biodiversity and ecosystem services? This question is highly relevant in Malawi where the research took place, but in other low-income countries in Africa with mostly agrarian populations, in which multi-scalar processes drive high food insecurity, alongside declining biodiversity, worsening land degradation and climate change. We analyse an innovative transdisciplinary agroecological approach that attempts to bridge the science-practice-policy gap by examining the potential of agro-ecological measures to enhance functional biodiversity and ecosystem services. This study involves a longitudinal, case-control and participatory research design in a region where thousands of farmers have experimented with agroecological practices, e.g., legume intercropping, composting, and botanical sprays. Innovative transdisciplinary agroecological research activities involved farmer participatory research, ecological monitoring and field experiments, social science methods (both qualitative and quantitative), participatory methodologies (public participatory Geographic Information Systems - PPGIS and scenario planning and testing) and stakeholder engagement to foster science-policy linkages. We discuss the theoretical and methodological implications of this novel transdisciplinary and participatory approach about pluralism, decolonial and translational ecological research to foster sustainability and climate resilience of tropical farming systems.

To document

Abstract

Chapter 8 provides a comprehensive review of literature pertaining to agroecological (AE) farming approaches/practices and knowledge driven from stakeholders’ and scientific studies. The review identifies the major drivers, barriers, gaps, and opportunities of AE practices in the context of African farming systems. The chapter presents the best combinations of AE practices as alternative approaches to the current unsustainable farming practices. Experiences from Zambia and other countries where selected AE practices are being implemented by farmers with the support of diverse stakeholders are shared in the chapter. Further, key ecological, social, and economic indicators developed in the countries are also discussed. The chapter analyses how the AE practices contribute to the reduction of GHG emissions and at the same time address the UN Sustainable Development Goals (SDGs), e.g., SDG 2 (food and nutrition security), SDG 12 (sustainable food production and consumption), SDG 13 (climate action), and SDG 15 (life on land).