Verdamping balans tussen noodzaak en overmaat: Kennisinventarisatie en analyses van vocht gerelateerde fenomenen in lopende projecten

Wageningen UR Greenhouse Horticulture made an inventarisation of knowledge about evaporation in greenhouses regarding to energy saving. Evaporation is especially effective on the energy balance and water transport in the plant. The limitation of the evaporation in the night will have an effect on the water uptake by the roots, and thus on the Ca uptake. A too low absorption of water during the night will manifest itself in the first place in a lack of Ca related problem. The energy balance and a balance of moisture stress by affecting the plant through the stomata opening and have through that affect CO2 uptake. There is no single factor which can be used as a strong steering factor oriented to align the stomata in the night. Knowledge gaps around the water absorption and evaporation in the night are: how long can we permit a situation of high humidity in the early night; how can we steer water uptake by EC in relation to changes in weather; how can we optimize root activity and substrate volume; what is the minimum evaporation for Ca uptake during the night? In practice, minimizing evaporation means growing at higher humidity, with high isolation and little air movement.