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
Authors
Jinbo Gao Wenjun Zhou Yuntong Liu Liqing Sha Qinghai Song Youxing Lin Guirui Yu Junhui Zhang Xunhua Zheng Yunting Fang John Grace Junbin Zhao Jianchu Xu Heng Gui Fergus Sinclair Yiping ZhangAbstract
Litter comprises a major nutrient source when decomposed via soil microbes and functions as subtract that limits gas exchange between soil and atmosphere, thereby restricting methane (CH4) uptake in soils. However, the impact and inherent mechanism of litter and its decomposition on CH4 uptake in soils remains unknown in forest. Therefore, to declare the mechanisms of litter input and decomposition effect on the soil CH4 flux in forest, this study performed a litter-removal experiment in a tropical rainforest, and investigated the effects of litter input and decomposition on the CH4 flux among forest ecosystems through a literature review. Cumulative annual CH4 flux was −3.30 kg CH4-C ha−1 y−1. The litter layer decreased annual accumulated CH4 uptake by 8% which greater in the rainy season than the dry season in the tropical rainforest. Litter decomposition and the input of carbon and nitrogen in litter biomass reduced CH4 uptake significantly and the difference in CH4 flux between treatment with litter and without litter was negatively associated with N derived from litter input. Based on the literature review about litter effect on soil CH4 around world forests, the effect of litter dynamics on CH4 uptake was regulated by litter-derived nitrogen input and the amount soil inorganic nitrogen content. Our results suggest that nitrogen input via litter decomposition, which increased with temperature, caused a decline in CH4 uptake by forest soils, which could weaken the contribution of the forest in mitigating global warming.
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No abstract has been registered
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No abstract has been registered
Academic – Long-term grassland productivity with and without ploughing
Ievina Sturite, Samson Øpstad
Abstract
Several studies conclude that permanent and temporary swards are equally productive, given equal management. In Norway, one experimental field trial has been maintained since 1974 (Fureneset; 61°18’N, 5°4’E). This ongoing experiment includes long-term/permanent ley (no-tillage over 25 and 45 years) next to temporary leys reseeded regularly. The objective of the study was to test reseeding/ renovation methods that may maintain long-term forage productivity. We hypothesized that sod seeding after chemical fallowing improves grassland productivity equally to that from reseeding after ploughing. In 2017, the frequently ploughed treatments, and half of the 25-year-old sward, were renewed by ploughing and reseeding with grass-clover seed mixtures. The second half of the 25-year-old sward was chemically fallowed and sod-seeded. The treatments included three different fertilizer strategies: mineral fertilizer (210 N kg ha-1) and cattle slurry in combination with mineral fertilizer (210 and 340 kg total-N kg ha-1). On average for four production years (2018-2021) the dry matter yield (DMY) of permanent sod-seeded 25-year-old ley was about 11 t ha-1, and these yields were equal to swards renewed by ploughing and reseeding.
Abstract
Mountain birch forest covers large areas in Eurasia, and their ecological resilience provides important ecosystem services to human societies. This study describes long-term stand dynamics based on permanent plots in the upper mountain birch belt in SE Norway. We also present forest line changes over a period of 70 years. Inventories were conducted in 1931, 1953, and 2007. Overall, there were small changes from 1931 up to 1953 followed by a marked increase in biomass and dominant height of mountain birch throughout the period from 1953 to 2007. In addition, the biomass of spruce (Picea abies) and the number of plots with spruce present doubled. The high mortality rate of larger birch stems and large recruitment by sprouting since the 1960s reveal recurrent rejuvenation events after the earlier outbreak of the autumnal moth (Epirrita autumnata). Our results demonstrate both a high stem turnover in mountain birch and a great ability to recover after disturbances. This trend is interpreted as regrowth after a moth attack, but also long-term and time-lagged responses due to slightly improved growth conditions. An advance of the mountain birch forest line by 0.71 m year−1 from 1937 to 2007 was documented, resulting in a total reduction of the alpine area by 12%. Most of the changes in the forest line seem to have taken place after 1960. Regarding silviculture methods in mountain birch, a dimension cutting of larger birch trees with a cutting interval of c. 60 years seems to be a sustainable alternative for mimicking natural processes.
Authors
Shu Zhang Lingbo Meng Jian Hou Xiaodan Liu Abiola O. Ogundeji Zeyu Cheng Tengjiao Yin Nicholas Clarke Baozhong Hu Shumin LiAbstract
No abstract has been registered
Authors
Arne SteffenremAbstract
No abstract has been registered
Authors
Kirsten Tørresen Jukka Salonen Lars Olav Brandsæter Björn Ringselle Marian M. Weigel Eliyeh Ganji Bärbel GerowittAbstract
Book of Abstracts p. 213: The perennial creeping weeds Cirsium arvense (L.) Scop., Sonchus arvensis L. and Elymus repens (L.) Gould cause large problems in agricultural production in northern Europe. The management of these species is difficult in organic farming, but easier in conventional farming using herbicides. We collected and analysed literature on the response of these weed species to management practices in order to find knowledge gaps. C. arvense and E. repens are more studied compared to S. arvensis. Both C. arvense and E. repens have recently been the subjects of extended reviews. Elymus repens, a rhizomatous grass, is vulnerable to disturbance and competition due to weak seasonal dormancy, shallow creeping rhizomes and short-lived and low-spreading seeds. Tillage and mowing can effectively control E. repens, but efficacy varies between clones, seasons and treatment frequencies. Combined effects of direct control and competition from main crop/subsidiary crop merit further research. Cirsium arvense and S. arvensis are dicot species with creeping roots, with C. arvense roots being situated deeper in the soil than S. arvensis and both having deeper roots than the rhizomes of E. repens. Cirsium arvense can sprout from the intact root system even below the plough layer. Spring tillage has been shown to control C. arvense better than autumn tillage, and horizontal root cutter (prototype) have promising results on this species. Sonchus arvensis sprouts mainly in spring and summer thus indicating seasonal dormancy. Therefore, spring tillage controls S. arvensis better than autumn tillage. The effect of competition from main crop and subsidiary crops needs further investigation. While E. repens and C. arvense can be significantly controlled by a simple mechanical control strategy alone (repeated tillage and deep root disturbance, respectively), S. arvensis must be managed by a combination of different non-chemical methods. Identified gaps focus on the deep root system and sexual reproduction (C. arvense), the link between disturbance, competition, withering and dormancy in roots (S. arvensis), and the long-term effect of different integrated weed management strategies on the population dynamics (E. repens). We conclude that more research on all three species is needed, especially on the less studied S. arvensis. Keywords: Couch grass, creeping thistle, perennial sow-thistle, mechanical control, crop competition, cover crop, subsidiary crop Acknowledgements: This research was part of the project “AC/DC-weeds- Applying and Combining Disturbance and Competition for an agro-ecological management of creeping perennial weeds” funded within the ERA-Net Cofund SusCrop/EU Horizon 2020, Grant no. 771134.
Authors
Frode VeggelandAbstract
No abstract has been registered
Authors
Pekka E. Kauppi Gustav Stål Lina Arnesson-Ceder Isabella Hallberg Sramek Hans Fredrik Hoen Arvid Svensson Iddo K. Wernick Peter Högberg Tomas Lundmark Annika NordinAbstract
Planting new forests has received scientific and political attention as a measure to mitigate climate change. Large, new forests have been planted in places like China and Ethiopia and, over time, a billion hectares could become available globally for planting new forests. Sustainable management of forests, which are available to wood production, has received less attention despite these forests covering at least two billion hectares globally. Better management of existing forests would improve forest growth and help mitigate climate change by increasing the forest carbon (C) stock, by storing C in forest products, and by generating wood-based materials substituting fossil C based materials or other CO2-emission-intensive materials. Some published research assumes a trade-off between the timber harvested from existing forests and the stock of C in those forest ecosystems, asserting that both cannot increase simultaneously. We tested this assumption using the uniquely detailed forest inventory data available from Finland, Norway and Sweden, hereafter denoted northern Europe. We focused on the period 1960 – 2017, that saw little change in the total area covered by forests in northern Europe. At the start of the period, rotational forestry practices began to diffuse, eventually replacing selective felling management systems as the most common management practice. Looking at data over the period we find that despite significant increases in timber and pulp wood harvests, the growth of the forest C stock accelerated. Over the study period, the C stock of the forest ecosystems in northern Europe increased by nearly 70%, while annual timber harvests increased at the about 40% over the same period. This increase in the forest C stock was close to on par with the CO2-emissions from the region (other greenhouse gases not included). Our results suggest that the important effects of management on forest growth allows the forest C stock and timber harvests to increase simultaneously. The development in northern Europe raises the question of how better forest management can improve forest growth elsewhere around the globe while at the same time protecting biodiversity and preserving landscapes.