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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.

2018

Abstract

A number of factors such as low soil temperature, desiccation and thatch can be serious limiting factors for the successful reestablishment of golf greens following winter damages. The rate of germination and seedling root growth have important implications for competition between species on a golf green. This research project has shown that P. annua is a very competitive species, due to quicker germination at lower temperatures, especially compared to A. stolonifera and F. rubra ssp communtata. Root growth of P.annua was also significantly quicker than of the Agrostis species tested. Seedlings of Agrostis species and F.rubra ssp commutata that germinate in close proximity to P. annua seedlings stand a large chance of being choked out. In order to reduce competition with P.annua, early seeding should be avoided. In this study, no difference in turfgrass establishment wasobserved when seedlings were grown using soil water extracts or soil from an ice-encased green,compared to a control. However, further investigations regarding reestablishment following iceencasement are warrant, and should be investigated on older greens with a higher organic mattercontent. The results from the demonstration trials emphasize the importance of using a sowingtechnique that ensures proper seed – soil contact. This is of particular importance for theestablishment of turfgrass species on golf greens, due to the high risk of desiccation.

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Abstract

Multilocation testing remains the main tool for understanding varietal responses to the environment. Here, Latvian and Norwegian hull-less and hulled barley varieties were tested in field experiments in Latvia and Norway in order to assess the varieties adaptability across environments (sites). Two Latvian (cv Irbe and cv Kornelija) and one Norwegian hull-less barley variety (cv Pihl) were tested along with one Latvian (cv Rubiola) and one Norwegian hulled barley variety (cv Tyra) under conventional and organic management systems. The grain yield, together with physical and chemical grain parameters were compared, and variety yield and protein stability detemined. Overall, grain yield of hull-less barley varieties was significantly lower than for hulled barley varieties regardless of climatic conditions and management system. However, in the organic farming systems this difference between barley types was less pronounced. The hull-less barley varieties cv Pihl and cv Irbe, along with both hulled varieties, had good yield stability across environments and were well adapted to both cropping systems. Hull-less barley varieties tended to contain more protein and β -glucans than hulled barley varieties. Despite being bred for local conditions in Norway and Latvia, our study shows that all the varieties used may be successfully transferred across countries.

Abstract

Sclerotinia stem rot (SSR) is the most important disease of oilseed Brassica crops in Norway. Fungicide applications should be aligned with the actual need for control, but the SSR prediction models used lack accuracy. We have studied the importance of precipitation, and the role of petal and leaf infection for SSR incidence by using data from Norwegian field and trap plant trials over several years. In the trials, SSR incidence ranged from 0 to 65%. Given an infection threshold of 25% SSR, regression and Receiver Operating Characteristics (ROC) analysis were used to evaluate different precipitation thresholds. The sum of precipitation two weeks before and during flowering appeared to be a poor predictor for SSR infection in our field and trap plant trials (P = 0.24, P = 0.11, respectively). Leaves from three levels (leaf one, three, five), and petals were collected at three to four different times during flowering from nine field sites over two years and tested for SSR infection with real-time PCR. Percentage total leaf and petal infection explained 57 and 45% of variation in SSR incidence, respectively. Examining the different leaves and petals separately, infection of leaf three sampled at full flowering showed the highest explanation of variation in later SSR incidence (R2 = 65%, P < 0.001). ROC analysis showed that given an infection threshold of 45%, both petal and leaf infection recommended spraying when spraying was actually needed. Combining information on petal and leaf infection during flowering with relevant microclimate factors in the canopy, instead of the sum of precipitation might improve prediction accuracy for SSR.

Abstract

In cold-temperate climate with high soil water content in spring, the farmer often faces the choice between topsoil compaction during seedbed preparation and delayed sowing, both of which may reduce attainable cereal yield. The objective of this study was to explore whether future climate change with increasing precipitation would aggravate this dilemma. We generated weather based on historical and projected future climate in Southeastern and Central Norway. Using this weather data as input, we simulated spring workability, attainable yield, timeliness costs, and mechanization management with a workability model and a mechanization model. The projected climate changes resulted in improved workability for spring fieldwork and higher attainable yield in South-eastern Norway, and either positive or negative changes in Central Norway compared to historical conditions. We observed a general increase in variability of workability and attainable yield, and a larger risk of extremely unfavourable years in the most unfavourable scenarios in Central Norway. Changes in profitability and mechanization management were small, but followed the same pattern. The negative effects in the most unfavourable climate scenarios in Central Norway were in contrast to positive effects in earlier studies. We explained discrepancies by differences in research methods and purpose. However, simulated sowing dates of annual crops should consider workability of the soil, in terms of water content. Under worst-case conditions, in need of a certain time window to complete their spring fieldwork, farmers might adapt to impaired spring workability by working the soil at higher water content than simulated in our study. The consequence would be a larger loss of attainable yield and less profitability in the future. We anticipate that negative effects may also be expected in other northern cold-temperate regions with high soil water content in spring.