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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.

2011

2010

Abstract

The model FROSTOL simulates course of frost tolerance in winter wheat on a daily basis from sowing on as affected by soil temperature (2 cm), snow cover, phenological development, and a genotypic maximum level of frost tolerance (LT 50). A series of cultivar trials in Finland was used to evaluate the model's ability to estimate plant survival in natural field environments during winters with differing weather conditions. Recorded survival was compared with number of intersections between the curves of simulated LT50 and the soil temperature curve for each field. A cumulative stress level (CSL) was calculated based both on number of intersections and FROSTOL simulated stress levels. The correlation between CSL and field recordings was quite low. While the field trials characterize a general ability to stand various types of winter stress, FROSTOL estimates damage caused by the soil temperature regime only. However, FROSTOL simulations seemed to correspond reasonably well to field observations when low temperature was the eventual cause of damage.

2009

To document

Abstract

Yields are reported from four long-term (16 30 years) tillage trials, comparing results since 1998, under relatively wet conditions, with earlier experience. In trial 1, on clay loam, mean grain yield with spring harrowing only, has since 1998 been 87% of that obtained with autumn ploughing, whereas it was 94% for the whole period since 1991. The inclusion of autumn harrowing increased these figures to 94 and 98%, respectively. Over the last six years, spring ploughing gave 5% lower yield than did autumn ploughing. Relative yields of unploughed versus ploughed treatments were negatively correlated with summer rainfall. Grain protein was lowest with spring harrowing only. In trial 2, on clay loam, direct drilling has since 1998, as in previous years, given around 10% lower yield than has autumn ploughing. Autumn harrowing gave 4% lower yield in winter wheat and 6% higher yield in spring oats than did autumn ploughing, whilst yields of spring turnip rape were not significantly affected by tillage. In trial 3, also on clay loam, six alternative straw treatments were compared under four unploughed tillage regimes. Relative to straw removal, retaining large residue amounts depressed yields hardly at all with autumn and spring harrowing, but by 7% with spring harrowing only and by 13% with direct drilling. Overall, direct drilling gave 18% lower yields in this trial than did autumn and spring harrowing, whilst the yield reduction with spring harrowing only was 7%. In trial 4, on silt loam, both spring harrowing only and direct drilling have since 1998 given 6% lower yield than has autumn ploughing, whereas autumn and spring harrowing has given 6% higher yield. Under drier conditions during 1991 1997, autumn ploughing gave up to 11% lower yield than did unploughed treatments. Straw retention was beneficial in the absence of ploughing during that period, but has had little effect in more recent years.