The ability to measure and assess new parameters during a very short time period enables the use of this system as part of a modern climate and irrigation control system.
Today, growers manage the crops to the best of their knowledge. The new capabilities offered by this system can significantly improve the management and control methods employed by growers. The development of a climate control application based on the plant growth rates and climate recorded in the previous day and the climate forecast can definitely improve the growth results.
Estimation of the pool size of assimilates created during the previous day,- based on the net photosynthesis rate and the plant's growth during the previous day - will assist to determination of strategy and set points for the following day.
Illustrates the impact of the previous day’s radiation conditions on the growth is presented in graph (1). Day with low radiation will perform “normal” growth rate as assimilate pool from previous day will provide assimilate required for growth.
Graph no. 1: The growth rate during a low radiation day (B ) that follows a high radiation day C is accompanied with high growth . The growth rate during a high radiation day A, that follows a low radiation day B, is low.
An interesting phenomenon observed in various places is the effect of wind direction and intensity on the growth rate pattern of the plants.
The existing control systems enable to regulate the opening of windows according to the wind direction and intensity.
However, these applications do not take into consideration the wind behaviour and its impact on plant growth inside the greenhouse.
It is clear and known that plants react very quickly to air flow inside the greenhouse, especially when the level of air humidity is low.
The following example (Graph 2) illustrates the outside wind impact on the growth rates in various compartments inside the greenhouse. Significant differences in growth rates were observed in various compartments when the wind direction or its intensity changed. The damage caused to the crops during those days was expressed in a drop in the growth rate and increased uniformity within the greenhouse.
I believe we need a model that describes the air flow within the greenhouse. Such a model could ensure better adjustment of the windows control and air circulation inside the greenhouse.
Graph 2: the effect of wind direction on growth rates in the greenhouse . the wind direction affected the general growth rate and decreased the differences between the greenhouse compartments.
This article is the 4th publication in a special series of articles on HortiDaily this month.
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