Prediction of the strawberry season in Norway

Abstract

The season for commercial strawberry growing in five districts of Norway was studied, and the characteristics of the strawberry season are described. For one district, Valldal, reliable yield data for the years 1967-1999 were available; this long time series made a good basis for statistical calculations. Large variations between years and between districts regarding the start, top and end of the season were found. The difference in season was about 1 month between the earliest and latest districts of Norway. A cubic equation was fitted to accumulated yield as related to time. The start and top of season were negatively correlated to May and June temperatures: 1°C higher June mean temperature gave 4.1 days' earlier season. End of season was negatively correlated to June and July temperatures. Regressions with temperatures as variables for predicting the start, top and end of the season were estimated. Regression models gave more reliable predictions than the use of heat units. The regression method for predicting the start, top and end of the season may be valuable for growers and for marketing organizations. © 2001 Taylor & Francis.