Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2021
Forfattere
Nicholas Clarke Lars Pødenphant Kiær O. Janne Kjønaas Teresa Gómez de la Bárcena Lars Vesterdal Inge Stupak Leena Finér Staffan Jacobson Kestutis Armolaitis Dagnija Lazdina Helena Marta Stefánsdóttir Bjarni D. SigurdssonSammendrag
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Sammendrag
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Forfattere
Inge Stupak Nicholas Clarke Andis Lazdins Iveta Kabasinskiene Diana Lukmine Dagnija LazdinaSammendrag
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Forfattere
Palingamoorthy Gnanamoorthy Qinghai Song Junbin Zhao Yiping Zhang Yuntong Liu Wenjun Zhou Liqing Sha Zexin Fan Pramit Kumar Deb BurmanSammendrag
Subtropical forests are important ecosystems globally due to their extensive role in carbon sequestration. Extreme climate events are known to introduce disturbances in the ecosystem that cause long-term changes in carbon balance and radiation reflectance. However, how these ecosystem function changes contribute to global warming in terms of radiative forcing (RF), especially in the years following a disturbance, still needs to be investigated. We studied an extreme snow event that occurred in a subtropical evergreen broadleaved forest in south-western China in 2015 and used 9 years (2011–2019) of net ecosystem CO2 exchange (NEE) and surface albedo (α) data to investigate the effect of the event on the ecosystem RF changes. In the year of the disturbance, leaf area index (LAI) declined by 40% and α by 32%. The annual NEE was −718 ± 128 g C m−2 as a sink in the pre-disturbance years (2011–2014), but after the event, the sink strength dropped significantly by 76% (2015). Both the vegetation, indicated by LAI, and α recovered to pre-disturbance levels in the fourth post-disturbance year (2018). However, the NEE recovery lagged and occurred a year later in 2019, suggesting a more severe and lasting impact on the ecosystem carbon balance. Overall, the extreme event caused a positive (warming effect) net RF which was predominantly caused by changes in α (90%–93%) rather than those in NEE. This result suggests that, compared to the climate effect caused by forest carbon sequestration changes, the climate effect of α alterations can be more sensitive to vegetation damage induced by natural disturbances. Moreover, this study demonstrates the important role of vegetation recovery in driving canopy reflectance and ecosystem carbon balance during the post-disturbance period, which determines the ecosystem feedbacks to the climate change.
Sammendrag
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Sammendrag
Biochar-based fertilizer products (BCF) are receiving increasing attention as potential win-win solutions for mitigating climate change and improving agricultural production. BCFs are reported to increase yields through increased N use efficiency, an effect which is often assumed to result from the slow-release of adsorbed N forms into the soil. Here, we review the magnitude of this effect, the potential for further improvement and the need to consider other mechanisms in product development. Current high-N commercial BCFs are mostly physical blends of biochar and mineral fertilizer, with little evidence of slow-release effects supported by sorption mechanisms. For such products, the main effect potentially results from root-growth promoting factors and from increases in soil pH and Eh and stimulation of beneficial micro-organisms in the rhizosphere, which all result in an increase in uptake of specific nutrients. Our reanalysis of literature data indicates that the median sorption capacity of untreated biochar for mineral N forms requires applying 200 times more biochar than N fertilizer. This ratio needs reducing by at least an order of magnitude for producing efficient sorption-based BCFs. Activation of biochar with acids and oxidizing agents, as reported in many studies, appears to only marginally increase sorption capacity in absolute values. Fixation of clay and organics within the porous structure of biochar appears a more promising technology, suggesting that macro- and mesoporosity is a key biochar property that deserves greater scrutiny and research towards making efficient sorption-based BCFs. Mechanisms of action and dose responses need to be more systematically studied in order to devise products that combine positive effects and can be used within realistic agronomic management practices. Long-term effects resulting from accumulated annual inputs of BCF also need to be better evaluated in terms of nutrient cycling and the progressive improvement of soil health.
Forfattere
Wenjun Zhou Jing Zhu Hongli Ji John Grace Liqing Sha Qinghai Song Yuntong Liu Xiaolong Bai Youxing Lin Jinbo Gao Xuehai Fei Ruiwu Zhou Jianwei Tang Xiaobao Deng Guirui Yu Junhui Zhang Xunhua Zheng Junbin Zhao Yiping ZhangSammendrag
With large area of primary tropical rainforest converted into rubber (Hevea brasiliensis) plantation in Southeast Asia, it is necessary to examine the change in soil CO2 and CH4 emissions, and their underlying drivers in tropical rainforest (TRF) and rubber plantation. In TRF and RP in Xishuangbanna Southwest China, we measured the soil CO2 , CH4 , temperature, and water content once each week from 2003 to 2008, and twice weeks in 2013 and 2014. Additionally, the concentrations of soil carbon (C) and nitrogen (N) fractions from 2013 to 2014 were observed. Inputs of litter and live, dead, decomposed fine roots dynamics were also included. TRF transplanted to RP did not change significantly the annual soil CO2 emissions (TRF, 359 ± 91 and RP 352 ± 41 mg CO2 m−2 h−1) but decreased soil CH4 uptake significantly (TRF, −0.11 ± 0.18 mg CH4 m−2 h−1) RP, −0.020 ± 0.087 mg CH4 m−2 h−1). The most important influence on soil CO2 and CH4 emissions in the RP was the leaf area index and soil water content, respectively, whereas the soil water content, soil temperature, and dead fine roots were the most important factors in the TRF. Variations in the soil CO2 and CH4 caused by land-use transition were individually explained by soil temperature and fine root growth and decomposition, respectively. The results show that land-use change varied the soil CH4 and CO2 emission dynamics and drivers by the variation of soil environmental and plant's factors.
Forfattere
Junbin Zhao Sparkle L. Malone Christina L. Staudhammer Gregory Starr Henrik Hartmann Steven. F. OberbauerSammendrag
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Forfattere
Sparkle L. Malone Junbin Zhao John S. Kominoski Gregory Starr Christina L. Staudhammer Paulo C. Olivas Justin C. Cummings Steven F. OberbauerSammendrag
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Sammendrag
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