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
Yield maps give farmers information about growth conditions and can be a tool for sitespecific crop management. Combine harvesters may provide farmers with detailed yield maps if there is a constant flow of a certain amount of biomass through the yield sensor. This is unachievable for grass seeds because the weight of the intake is generally too small to record the variation. Therefore, there is a need to find another way to make grass seed yield maps. We studied seed yield variation in two red fescue (Festuca rubra) fields with variation in management and soil fertility, respectively. We estimated five vegetation indices (VI) based on RGB images taken from a drone to describe yield variation, and trained prediction models based on relatively few harvested plots. Only results from the VI showing the strongest correlation between the index and the yield are presented (Normalized Excess Green Index (ExG) and Normalized Green/Red Difference Index (NGRDI)). The study indicates that it is possible to predict the yield variation in a grass field based on relatively few harvested plots, provided the plots represent contrasting yield levels. The prediction errors in yield (RMSE) ranged from 171 kg ha-1 to 231 kg ha-1, with no clear influence of the size of the training data set. Using random selection of plots instead of selecting plots representing contrasting yield levels resulted in slightly better predictions when evaluated on an average of ten random selections. However, using random selection of plots came with a risk of poor predictions due to the occasional lack of correlation between yield and VI. The exact timing of unmanned aerial vehicles (UAVs) image capture showed to be unimportant in the weeks before harvest.
Authors
Therese With BergeAbstract
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Abstract
Pyrolysis is a valid thermos-chemical process of energy production that produces biochar from potentially harmful biomasses. This study aims to investigate the pyrolytic conversion of olive mill solid residues (OMSR) into biochar, with the aim of characterizing this product towards applications for soil improvement and soil C sequestration. Production parameters of OMSR-biochar (OB) and physico-chemical characteristics were analyzed and compared with published data to assess the potential of OB to serve as a soil amendment and soil C sequestration method. The slow pyrolysis of OMSR at 450° leads to a good proportion between produced products (fuels liquid and gas, and solid), and generates about the 35% of OB. In turn, this product reveals the absence of phytotoxicity, the presence of exchangeable surface cations, structure, particle size distribution and external surface groups suitable for agricultural uses, and high C content with a potential long lasting in soil. The physico-chemical characteristics of OB reported here suggest that OB could be used for improving soils and increasing C sequestration in a sustainable way.
Abstract
No abstract has been registered
Authors
Isabell Eischeid Jesper Madsen Rolf Anker Ims Bart A. Nolet Åshild Ønvik Pedersen Kees H.T. Schreven Eeva Marjatta Soininen Nigel Gilles Yoccoz Virve RavolainenAbstract
Arctic tundra vegetation is affected by rapid climatic change and fluctuating herbivore population sizes. Broad-billed geese, after their arrival in spring, feed intensively on belowground rhizomes, thereby disturbing soil, mosses, and vascular plant vegetation. Understanding of how springtime snowmelt patterns drive goose behavior is thus key to better predict the state of Arctic tundra ecosystems. Here, we analyzed how snowmelt progression affected springtime habitat selection and vegetation disturbance by pink-footed geese (Anser brachyrhynchus) in Svalbard during 2019. Our analysis, based on GPS telemetry data and field observations of geese, plot-based assessments of signs of vegetation disturbance, and drone and satellite images, covered two spatial scales (fine scale: extent 0.3 km2, resolution 5 cm; valley scale: extent 30 km2, resolution 10 m). We show that pink-footed goose habitat selection and signs of vegetation disturbance were correlated during the spring pre-breeding period; disturbances were most prevalent in the moss tundra vegetation class and areas free from snow early in the season. The results were consistent across the spatial scales and methods (GPS telemetry and field observations). We estimated that 23.4% of moss tundra and 11.2% of dwarf-shrub heath vegetation in the valley showed signs of disturbance by pink-footed geese during the study period. This study demonstrates that aerial imagery and telemetry can provide data to detect disturbance hotspots caused by pink-footed geese. Our study provides empirical evidence to general notions about implications of climate change and snow season changes that include increased variability in precipitation.
Abstract
No abstract has been registered
Authors
Ji Liu Yi Wang Yong Li Josep Peñuelas Ying Zhao Jordi Sardans Doerthe Tetzlaff Jian Liu Xinliang Liu Hongzhao Yuan Yanyan Li Ji Chen Jinshui WuAbstract
Whether and how to synchronously regulate stream water nitrogen (N) and phosphorus (P) concentrations and ratios is a major challenge for sustainable aquatic functions. Soil carbon (C):N:P ratios influence soil N and P stocks and biogeochemical processes that elicit subsequent substantial impacts on stream water N and P concentrations and ratios. Therefore, bridging soil and stream water with ecological stoichiometry is one of the most promising technologies for improving stream water quality. Here, we quantified the ecological stoichiometry of soil and stream water relationships across nine catchments. Soil C:P ratio was the main driver of water quality, showing negative correlations with stream water N and P concentrations, and positive correlations with the N:P ratio in P-limited catchments. We revealed that soil C:P ratios higher than 97.8 mol mol−1 are required to achieve the simultaneous regulation of stream water N and P concentrations below the eutrophication threshold and make algal growth P-limited. Furthermore, we found that the relationships between catchment landscape and soil ecological stoichiometry likely provided practical options for regulating soil ecological stoichiometry. Our work highlights that soil ecological stoichiometry can effectively indicate the amount and proportion of soil N and P losses, and can be intervened through rational landscape planning to achieve sustainable aquatic ecosystems in catchments.
Abstract
No abstract has been registered
Abstract
No abstract has been registered