THE INFLUENCE OF INSULATION TECHNIQUES ON CROP PRODUCTION AND PROFITABILITY IN THE DUTCH GLASSHOUSE INDUSTRY

A.P. Verhaegh
A considerable fuel saving can be obtained with thermal screens, double glazing, coated glass or twin-skinned plastics. However the decrease in light transmission applicated with these insulating factors, often causes a substantial loss in production. The savings in fuel costs must be at least the annual costs of the technique (depriciation, interest, maintenance) as well as the decline in revenues due to crop loss.

Tomatoes planted in the period of 15–31 December are very sensitive to the total incoming radiation in the period before week 17 (before April 21). During the fruitgrowingperiod a decrease of 10% in the total radiation will cause before week 17 a yield reduction of 31%. The yield in week 17 up to week 20 inclusive appears to less sensitive, as a 10% reduction in radiation cause a 10% decrease in yield production. After May 18 till beginning of July no correlation is found between radiation and yield.

Tomatoes planted during the month of February appear to be sensitive for radiation till week 25 (before June 16); 10% radiation decrease is equivalent to 14% yield reduction.

The crop losses expressed in guilders were greater, because the market price for the early harvest is higher than for the yield harvested; later in the season.

At the present gasprice DFL. 0,21 per cubic meter the savings in fuel cost are equal or lower than the loss in revenue due to the lower production, therefore the investment for the extra insulation would not pay for itself. Even at the predicted gasprice of DFL. 0,27 per cubic meter for next year (1981) for low heat demanding crops the savings in fuel cost are lower than the loss in revenues., for other crops the positive balance is not enough. Only for high heat demanding crops such as tropical foliage plants a thermal screen is justifiable from a business economic point of view.

Verhaegh, A.P. (1981). THE INFLUENCE OF INSULATION TECHNIQUES ON CROP PRODUCTION AND PROFITABILITY IN THE DUTCH GLASSHOUSE INDUSTRY. Acta Hortic. 115, 453-466
DOI: 10.17660/ActaHortic.1981.115.51
https://doi.org/10.17660/ActaHortic.1981.115.51

Acta Horticulturae