Ingunn Øvsthus
Forsker
(+47) 482 07 250
ingunn.ovsthus@nibio.no
Sted
Ullensvang
Besøksadresse
NIBIO Ullensvang, 5781 Lofthus
Sammendrag
In organic plant production, nitrogen (N) availability is often a growth-limiting factor. Under such conditions, off-farm waste-derived nutrient resources may be an alternative to meet the N demand. In this study, we described a production method for a shrimp shell (SS) pellet Product and evaluated the N fertiliser effect and N recovery efficiency (NRE) in a controlled climate pot experiment with potatoes. The experiment was set up with low, medium and high N levels of SS pellets in comparison with a standard mineral fertiliser (MF) at 9°C, 15°C and 21°C. In a separate study, we examined the loss of N as N2O from SS pellets in comparison with SS powder in a 100 days incubation experiment. The results documented the possibility to formulate a fertiliser pellet product from SS, and that SS pellets were an effective N fertiliser in potato at all Growth temperatures. Nevertheless, a slightly slower development and lower tuber yields than for MF indicated a delayed N-availability from SS pellet fertiliser. NRE after use of MF was around 90%, and about 70% for the different levels of SS pellets. The incubation experiment showed a higher rate of available N for SS powder than for pellets (67% and 39%, respectively) after 100 days of incubation at constant humidity and temperature. This difference was attributed to a lower degree of dissolved materials and a higher rate of denitrification and N2O emissions for pellets than for powder, probably caused by differences in physical properties, occurrence of anoxic hotspots and higher microbial activity around and inside the SS pellets.
Forfattere
Ingunn Øvsthus Randi Seljåsen Elizabeth Stockdale Christian Uhlig Torfinn Torp Tor Arvid BrelandSammendrag
More sustainable production of high-quality, nutritious food is of worldwide interest. Increasing nutrient recycling into food systems is a step in this direction. The objective of the present study was to determine nitrogen (N) fertiliser effects of four waste-derived and organic materials in a cropping sequence of broccoli, potato and lettuce grown at two latitudes (58° and 67° N) in Norway during three years. Effects of anaerobically digested food waste (AD), shrimp shell (SS), algae meal (AM) and sheep manure (SM) at different N application rates (80 and 170 kg N ha–1 for broccoli, and 80 and 60 kg N ha–1 for potato and lettuce, respectively) and residual effects were tested on crop yield, N uptake, N recovery efficiency (NRE), N balance, N content in produce, mineral N in soil, product quality parameters and content of nitrate in lettuce. Mineral fertiliser (MF) served as control. Effects on yield, N uptake, NRE, N balance and product quality parameters could to a great extent be explained by estimated potentially plant-available N, which ranked in the order of AD>SS>SM>AM. Results for crops fertilised with AD and SS were not significantly different from MF at the same N application rate, while AM, in agreement with its negative effect on N mineralisation, gave negative or near-neutral effects compared to the control. No residual effect was detected after the year of application. The results showed that knowledge about N dynamics of relevant organic waste-derived fertilisers is necessary to decide on the timing and rate of application.
Forfattere
Ingunn Øvsthus Tor Arvid Breland Sidsel Fiskaa Hagen Kirsten Brandt Anne-Berit Wold Gunnar Bengtsson Randi SeljåsenSammendrag
Organic vegetable production attempts to pursue multiple goals concerning influence on environment, production resources, and human health. In areas with limited availability of animal manure, there is a need for considering various off-farm nutrient resources for such production. Different organic and waste-derived fertilizer materials were used for broccoli production at two latitudes (58° and 67°) in Norway during two years. The fertilizer materials were applied at two rates of total N (80 and 170 kg ha–1) and compared with mineral fertilizer (170 kg ha–1) and no fertilizer. Broccoli yield was strongly influenced by fertilizer materials (algae meal < unfertilized control < sheep manure < extruded shrimp shell < anaerobically digested food waste < mineral fertilizer). Yield, but not glucosinolate content, was linearly correlated with estimated potentially plant-available N. However, extruded shrimp shell and mineral NPK fertilizer gave higher glucosinolate contents than sheep manure and no fertilizer. Sensory attributes were less affected by fertilizer material and plant-available N.
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Margarita Novoa-Garrido Celine Rebours Ingunn Øvsthus Marte Meland Christian Guido Bruckner Pierrick Stevant Christian Uhlig Åsbjørn KarlsenSammendrag
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Margarita Novoa-Garrido Celine Rebours Ingunn Øvsthus Marte Meland Christian Uhlig Åsbjørn KarlsenSammendrag
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Use of organic fertilizers in fish pond has been common since ancient times. Applying fertilizers stimulates the growth of phytoplankton, primary producers of the fish food chain. Artificial nitrogen and phosphorus fertilizers are nowadays the main types of nutrients supply in ponds. However, the use of mineral fertilizers is not sustainable due to the use of nonrenewable resource and the impact on the environment. Moreover, the Norwegian government has defined the national ambition that organic food production and food consumption should be more than 15% by 2020. Modern societies produce large amount of organic wastes, which could be reused. Ahead of utilizing such waste as fertilizers in aquaculture, the first step is to gain knowledge about the mineralization patterns in seawater. This knowledge is important to ensure proper supply time and proper amount of nutrients from waste for optimal production with minimal negative impact on the environment This poster will present a study about nitrogen mineralization pattern from organic materials relevant as fertilizers in sustainable aquaculture.
Forfattere
Ingunn ØvsthusSammendrag
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In Norway there is an incomplete resource management of side products and residuals from the main primary sectors of agriculture, fish farming and fishery. For example is the theoretically hitherto unused energy content in animal manure estimated to approximately 2,5 TWh per year, while Norwegian fish farming annually emits about 40.000 ton nitrogen and 8400 ton phosphorous into the coastal environments. Furthermore, recycling of nutrients and energy from marine fish waste of approximately 3.2 million ton fish is still at its early stages. The incomplete resource management results in environmental, economically and social costs. Consequently, an optimisation of national nutrient and energy cycling is required to increase sustainability. The establishment of individual driven resource optimisation enterprises, e.g. local biogas reactors, are often challenging both logistically and financially, particularly at relatively remote sites. This paper presents an overall conceptual approach to optimize energy and nutrient cycling, due to a cooperatively and integrated resource management system on a regional scale in Steigen, Northern Norway.
