ISHS Acta Horticulturae 97: VI Symposium on Horticultural Economics
SHORT TERM FORECASTING OF THE MARKET SUPPLY OF VEGETABLES, ESPECIALLY CAULIFLOWER |
| Author: | H.-J. Wiebe |
| Abstract:
The importance of the yield or harvest date for the forecasting of the market supply of vegetables depends on the crop. For crops with short growing periods the expected harvest date is a decisive factor of forecasting the course of harvest during the season. Deviations from the main growing period for the different sowing dates can be forecast by the determination of yield at an early date with the help of the harvesting of samples or simulation. The earlier climatic factors have a decisive influence on the growing period or yield, the earlier a prognosis is possible. For this cauliflower is a good example. The forecasting model described in this paper is based on results from experiments in growth chambers. Increasing temperatures shorten the duration of the phases of leaf formation and curd growth, but the time necessary for a full vernalization effect (a precondition for curd initiation) decreases up to 10 – 12°C only and then increases. These counteracting effects of temperature on the growth and development of cauliflower is the decisive precondition of a possible forecasting of the harvest date 3 weeks after planting. The described model has been tested during the last 4 years at a producer wholesale market in North Germany. The market has to record the following data weekly: planting date, number of plants, cultivars, long term and actual daily temperatures. The correlation between actual and market supply predicted 3 weeks after planting is with r = 0.68 relatively weak. The trend, however is relatively well forecast, but sometimes the change happens one week earlier or later. | |
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