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
Authors
Sekhar Udaya Nagothu M. Muralidhar M. Kumaran B. Muniyandi R. Umesh K.S. Krishna Prasad Sena S. De SilvaAbstract
Approximately 70% of shrimp consumed globally is farmed. India is ranked among the top five shrimp farming countries globally, and occurs mainly in the eastern coastal state of Andhra Pradesh (AP). More than 90% of the farms are less than 2 ha and are farmer owned, operated and managed. The objective of this study was to increase our understanding of climatic and socio-economic factors influencing this sector, through a survey of 300 shrimp farmers in AP in 2009/10. The farming communities were divisible into two groups: members of a society/cooperative and those operating individually. The latter were large scale adopting more intensive practices. The average production cost was Indian Rupees (IRS) 80,186 ha-1 and net income in summer and winter was IRS 221,901 and IRS 141,715, respectively. The mean technical efficiency estimated using Stochastic frontier function was 7% and 54%. The present study attempts to explain the difference in efficiencies using socio-economic and climatic variables, the latter being a novel approach. Among socio-economic variables, farming experience and membership in society were found to have a significant influence to improve technical and economic efficiencies. Further improvements in identifiable facets of the practices and a consequent increase in technical efficiency will make the sector less vulnerable to climatic change impacts.
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Signe Kynding Borgen Arne Grønlund Olof Andrén Thomas Kätterer Ole Einar Tveito Lars Bakken K PaustianAbstract
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Reidun Pommeresche Anne-Kristin LøesAbstract
Abstract: Little is known about Collembola in arable soil, at least in Norway. Recently, a study includ. this group has been initiated in a Norwegian field experiment (Soileffects). Collembola (springtails) are a group of small animals (1-3 mm) living in vegetation, litter and in the pores and caves in the soil to a depth of ca 15 cm. They are important decomposers of dead plant material, eating fungi, algae and microorganisms in soil and on organic debris. Their grazing and decomposing activity contribute significantly to the nutrient circulation in the soil. The name springtail refers to a furca on their back, usually folded in under the body, but released in need of a rapid escape. In one jump, Collembola can jump more than 50 times their own body length. In Norway 334 species are known; in the world more than 6000. Two main groups are found: Entomobryomorpha; species with a clearly elongated segmented body and Symphyleona; species with a more or less globular body with fused segments, reminding of small “rabbits”. Whereas species living in the vegetation and in the upper soil litter are often pigmented, have long antennas, large furca and visible eyes, soil living species are smaller (< 0.5 mm), and have shorter extremities and lack eyes or have small eyespot. They are often white or grey in color. The general distribution of species in Norway is well studied by Arne Fjellberg1. European papers about Collembola in agricultural soil are available23, but not too much is known about this group of animals in arable soil. On the organic research farm in Tingvoll, NW Norway, an experiment was established in 2011 to compare anaerobically digested manure with undigested slurry in perennial ley and arable crops. Effects on crop yields, soil fauna, microbial communities, soil structure, organic matter and nutrient concentration are recorded. There is limited information on how the manure digestion impacts soil fertility in the long run. A reduced supply of carbon to the soil may impact the soil fauna, which is dependent on this source of energy, because almost none of them produce organic matter themselves. In addition to earthworms, Collembola are studied in this project, called “Soileffects”. Collembola were sampled from 12 plots in the ley part of the Soileffects experimental trail in April 2011. This, to get a start characterization of the fauna. We used small metal rings (5,8 cm in diam, 3,8 cm high) to take out soil cores. The fauna in the samples were extracted by using a variant of Tullgren funnels, where drying the soil force the Collembola out. In cooperation with Arne Fjellberg, we found 250 collembolas and identified them to 17 species, comprising a large variation in colors and body forms. A mean of 21 individuals in each sample, gave an estimate of 7980 individuals m-2 in our ley field. We found species belonging to the Entomobryomorpha and species belonging to the Symphyleona. A numerous species was Isotomurus graminis, with a greenish color, medium long antenna and a solid furca. Isotoma viridis, also greenish, but with purple edges of each segment. In this species, the body hairs are better preserved in alcohol, than mostly found for I. graminis. Of the small, white soil living species, Protaphorura armata, Stenaphorura lubbocki and Mesaphorura macrochaeta were the most numerous species. Possible effects of 3 years manure application with anaerobically digested manure and non-digested manure (slurry) will be measured in 2013. 1 Fjellberg. 1998 and 2007. The Collembola of Fennoscandia and Denmark. Part I and II. Fauna Entoml. Scand. 2 Bardgett and Cook. 1998. Functional aspects of soil animal diversity in agricultural grasslands. Appl. Soil Ecol. 3 Gutierrez-Lopez et al.2011. Movement response of Collemb. to the excreta of two earthw….Soil Biol. Biochem.
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Introductions of the pine wood nematode (PWN), which causes Pine Wilt Disease (PWD), have devastating effects on pine forests in regions with susceptible host trees under suitable climate conditions. Norwegian authorities have proposed a contingency plan if PWN is detected in Norway. We compare the costs of implementing this plan with the costs of further spread and damage of PWN under two climate change scenarios: present and the most likely future climate. With the present climate, PWD will not occur in Norway. Under climatic change, the cost of PWD damage is approximately 0.078–0.157 million NOK (0.01–0.02 million Euros) estimated as net present value with 2 and 4% p.a. discount rate. In contrast, the corresponding costs of implementing the suggested contingency plan will be 1.7–2.2 billion NOK (0.2–0.25 billion Euros). These costs are caused by reduced income from industrial timber production and the costs of the eradication measures. Costs related to reduced recreation or biodiversity are expected to be very high, but are not included in the above estimates. Many of the factors in the analysis are burdened with high uncertainty, but sensitivity analyses indicate that the results are rather robust even for drastic changes in assumptions. The results suggest that there is a need to revise the current PWN contingency plan in Norway.