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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.

2012

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Abstract

This Technical brief is a short summary of the results obtained from the field trials conducted at Agro Climate Research Centre, Tamil Nadu Agricultural University, India to understand the Pest dynamics at elevated temperature. Among the major food crops, rice (Oryza sativa L.) forms the stable food for more than half of the world’s population. Among various constrains in rice production, losses due to pest is a major concern. Climate change resulting in increased temperature could impact crop insect pest populations in several complex ways. Although some climate change temperature effects might tend to depress insect populations, most researchers seem to agree that warmer temperatures in temperate climates will result in more types and higher populations of insects. Hence, it is important to understand the population growth of the important insect pests such as yellow stem borer (Scirpophaga incertulas) and brown planthopper (Nilaparvata lugens) of rice. The results revealed that there was an inverse correlation between temperature and total life span, developmental time and also fecundity. However there was a positive correlation between temperature and net reproductive rate and development rate.

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Abstract

This Technical brief is a short summary of the results obtained from the field trials conducted at Anbil Dharmalingam Agricultural College and Research Institute, Trichy, India during Rabi (2010-2011) to evaluate the role of photosynthetic diazotrophs in reducing methane flux from rice soil ecosystem as a part of climarice project. Global warming induced by increasing concentration of greenhouse gases (GHGs) in the atmosphere is a matter of great environmental concern. Methane, carbon dioxide, nitrous oxide and chlorofluorocarbon are the GHGs which have strong infrared absorption bands and trap part of the thermal radiation from the earth surface. Rice fields have to be considered as a significant source of greenhouse gases and rice field eco systems account for about 60 Tg methane per year or about 12 per cent of the global annual methane emission. The purpose of this study is to explore the potential of blue green algae and azolla in minimizing methane flux at source in paddy field ecosystem. In the present study, combined application of organics and blue green algae not only recorded higher yield, but also found to emit less methane in paddy cultivation than the application of organics alone.

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Abstract

Farmers attempt to develop a different environment for rice under System of Rice Intensification (SRI) method by which the rice plants can exhibit their full potential. Major principles of SRI includes perfect land levelling, lower seed rate, transplanting young seedlings of 12 days old, single seedling / hill with wider spacing (25 x 25 cm), careful water management (applying a minimum of water during vegetative growth and at later stages maintaining only one inch water) and weed management using cono weeder thrice in the vegetative stage. Researchers and farmers’ experience in the Cauvery basin in Tamil Nadu from ClimaRice have shown that yields of rice could be increased considerably (18–27%) with reduced water consumption (22- 25%) and less expenditure, just by following SRI method of cultivation. Thus it is beneficial for small and marginal farmers under changing climatic conditions.

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Abstract

Peat bogs have accumulated more atmospheric carbon (C) than any other terrestrial ecosystem today. Most of this C is associated with peat moss (Sphagnum) litter. Atmospheric nitrogen (N) deposition can decrease Sphagnum production, compromising the C sequestration capacity of peat bogs. The mechanisms underlying the reduced production are uncertain, necessitating multifactorial experiments.•We investigated whether glasshouse experiments are reliable proxies for field experiments for assessing interactions between N deposition and environment as controls on Sphagnum N concentration and production. We performed a meta-analysis over 115 glasshouse experiments and 107 field experiments.•We found that glasshouse and field experiments gave similar qualitative and quantitative estimates of changes in Sphagnum N concentration in response to N application. However, glasshouse-based estimates of changes in production – even qualitative assessments – diverged from field experiments owing to a stronger N effect on production response in absence of vascular plants in the glasshouse, and a weaker N effect on production response in presence of vascular plants compared to field experiments.•Thus, although we need glasshouse experiments to study how interacting environmental factors affect the response of Sphagnum to increased N deposition, we need field experiments to properly quantify these effects.

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Abstract

Insect outbreaks in northern-boreal forests are expected to intensify owing to climate warming, but our understanding of direct and cascading impacts of insect outbreaks on forest ecosystem functioning is deficient. The duration and severity of outbreaks by geometrid moths in northern Fennoscandian mountain birch forests have been shown to be accentuated by a recent climatemediated range expansion, in particular of winter moth (Operophtera brumata). Here, we assess the effect of moth outbreak severity, quantified from satellite-based defoliation maps, on the state of understory vegetation and the abundance of key vertebrate herbivores in mountain birch forest in northern Norway. We show that the most recent moth outbreak caused a regional-scale state change to the understory vegetation, mainly due to a shift in dominance from the allelopathic and unpalatable dwarf-shrub Empetrum nigrum to the productive and palatable grass Avenella flexuosa. Both these central understory plant species responded significantly and nonlinearly to increasing outbreak severity. We further provide evidence that the effects of the outbreak on understory vegetation cascaded to cause strong but opposite impacts on the abundance of the two most common herbivore groups. Rodents increased with defoliation, largely mirroring the increase in A. flexuosa, whereas ungulate abundance instead showed a decreasing trend. Our analyses also suggest that the response of understory vegetation to defoliation may depend on the initial state of the forest, with poorer forest types potentially allowing stronger responses to defoliation