ISHS Acta Horticulturae 228: IV International Symposium on Water Supply and Irrigation in the Open and under Protected Cultivation
THE ROLE OF INTERNAL AND EXTERNAL RESISTANCES IN SCHEDULING IRRIGATION OF A GREENHOUSE CROP |
| Author: | C. Stanghellini |
| Abstract:
Computer assisted irrigation scheduling in greenhouses requires a reliable ascertainment of transpirative water losses, on a time basis of a few minutes. On such a time scale, however, variations - which could otherwise be averaged out - of the resistance to vapour and heat transfer, may significantly affect transpiration rates. In this paper the role of external resistance (to vapour and heat transfer) as well as internal one (to vapour transfer) is discussed making use of experimental data. It is concluded that, as a first approximation, external resistance may be regarded as constant, for a given crop, while the internal one may be represented by an inverse exponential of shortwave irradiation. | |
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