The losses must be compensated through irrigation. Besides, it has been demonstrated in padded greenhouses with soil covered together with plastic blankets that the amount of evaporation is negligible. Inhibitors,Modulators,Libraries This happens when dealing with hydroponic cultivations [1]. According to this, water should be applied in precise Dasatinib supplier amounts to cover only water Inhibitors,Modulators,Libraries losses due to crop transpiration. Excess water would mean Inhibitors,Modulators,Libraries an excessive washing out of fertilizers. In turn, it could lead to contamination of the subterranean water, or the flooding of the substratum or radicular asphyxiation. Otherwise, a hydric deficit may be provoked if irrigation does not provide enough water. This can lead to a decrease in production and can even be dangerous for the crop growth.

Hence, Inhibitors,Modulators,Libraries automatic irrigation control systems are fundamental tools to supply water to the culture in the required amount and frequency. Moreover, as water is a limited resource in many agricultural areas, optimizing productivity through efficient and adequate Inhibitors,Modulators,Libraries irrigation is a basic objective. In order to design a good automatic irrigation system, the following questions Inhibitors,Modulators,Libraries must be answered: what should the frequency of the irrigations be, and how much water should be applied in the irrigation? To answer these questions, it is necessary to know how much water should be applied to replenish the losses due to the transpiration during the plant’s respiration.Measuring the water lost by transpiration is a way of obtaining the plant’s water demand.

This estimation of transpiration in different species grown in greenhouses has been developed, e.g.

, by Baille et al. [2] for ornamentals, Stanghellini [1], Jemaa [3], Drug_discovery Boulard [4] and Baille [2] for tomatoes, Montero Inhibitors,Modulators,Libraries et al. [5] for geranium crops, Medrano et al. [6] for cucumbers, Suay et al. [7] for rose cultivation, Voogt et al. [8] for chrysanthemums, and Schmidt and Exarchou [9] for gerbera pots, among others.In most of these works, the microlysimeter became the basic measurement device to record the water losses in crops, subtracting the water content in an instant (t) by the water content in another instant (t ? 1). However, on many occasions, Inhibitors,Modulators,Libraries the measurements were not continuous due to the irrigation process or during the water drainage.

Furthermore, it is seldom used by farmers since this device is expensive to acquire and to maintain.

From an operational point of view, it is important to find alternatives to this irrigation system gadget. Thus, virtual sensors based on transpiration become a good option to reduce total system cost, especially in the agriculture sector necessary where Batimastat profit margins are so narrow. Such virtual sensors must be based on sensors that are typically installed in greenhouses sellekchem for climate control (temperature, humidity, and solar radiation), thereby reducing the installations costs.Virtual sensors become a very efficient and powerful tool that has been successfully used in other fields [10�C12].