In recent years, there has been an increasing number of extreme weather events, such as periods with above-average intensity of precipitation, stormy weather, and the appearance of late spring frosts. Late spring frosts are one of the biggest enemies of vineyards and orchards. It can cause complete damage and loss of yield or lead to poor quality or delayed yield. In order to prevent such a consequence, it is necessary in addition to the already standard methods of protection (like crop insurance) apply an active protection measure in the form of a frost protection system.
The frost protection system (rainfall) is based on the phenomenon of water anomaly, when the change in the aggregate state of water from liquid to solid state releases energy used to maintain the temperature of flowers and young fruits at a temperature of 0 to -2 ºC. In this way, a moist ice crust is made over the flower and the fruit, the temperature of which is 0 ºC and is used to protect the fruit (needle effect).
The system must be started at least one hour before the expected frost (it starts when the temperature drops to +2 ° C in case we are sure of frost). By starting, the space we are protecting is filled with moisture and thus reduced evaporation. In this way we achieve a microclimate with 100% relative humidity and prevent heat loss by evaporation, while retaining the energy obtained by freezing water. The system is stopped after the air temperature rises above +2 ºC and the complete ice formed during protection melts.
The system can be switched on immediately and it will start working within 5 minutes and very quickly enable the protection of orchards (for cases when we have limit parameters for calculating the assessment of frost occurrence, ie when it is not possible to determine with certainty whether there will be frost or not, as well as in cases of sudden changes in weather conditions that are difficult to predict.
It is also possible to use the system in summer to cool orchards in order to raise the quality of the fruit. The frost protection system can be connected to an already existing irrigation system.
Protection technology is based on the creation of 100% moisture within the microclimate of the orchard. They use pulsating sprinklers that spray at the same time covering a radius of 5 meters. Each sprayer has a flow rate of 37 liters per hour. The described method saves energy because evaporation does not occur in the microclimate, since a 100% saturated atmosphere has already been created.
Other systems have a higher flow rate per sprayer, but are less efficient due to the rotation of the jet, which after passing one part of the circuit loses energy where it does not spray and there is unnecessary evaporation or loss of energy. Such systems have a greater need for water and create unnecessary ice deposits when protecting plantations.
The subject rainwater system has proven to be the most reliable and cost-effective way of protection, completely safe for the environment and energy efficient.
The frost protection system takes into account the following parameters:
- air temperature
wind speed and direction
phenophase of plant development
weather forecast and frost announcement
As each orchard has its own microclimate in addition to the microlocation, it is desirable to have a local meteorological station that measures current data from the orchard, and these parameters are used to operate the frost protection system.