We have to involve the crop itself in the automation and the control.

“What we currently do is steer the plant using the environment, but my question is whether that is a good approach. Would it not be better to look at the plant’s energy? We have to involve the crop itself in the automation and the control,” says Peter Kamp, crop systems innovator at Priva.

Managing water balance in the crop

On January 20, 2022, Peter presented at a webinar hosted by OMAFRA that focused on Priva’s BioLogics approach to greenhouse crop management. The BioLogics approach focuses on managing the water balance in the crop rather than focusing primarily on temperature management.

As Peter explains, monitoring the greenhouse temperature and other environmental parameters will always remain important but may not remain the most efficient way of steering crop growth. Similarly, focusing only on photosynthesis and the production of sugars does not paint the whole picture.

“Considering photosynthesis is really important because without the production of sugars, the plant cannot make different plant organs and grow. But it isn’t the only thing. When baking, only sugar and flour doesn’t make a cake. We need good insight into water balance,” says Peter.

Crop steering according to water balance requires an understanding of water uptake, fixation by the plant and transpiration. To do so, Peter has worked diligently with Priva’s Horticulture Innovation Lab and with growers to develop growth curves that graph the transpiration rate over time. The curves include both an upper and lower limit beyond which the crop suffers dramatically, as well as an inner envelope where optimal growth occurs. On this curve, Peter has identified six setpoints that could be used to steer the crop.

Reducing the number of setpoints

“With Priva’s BioLogics for plant growth, we want to reduce the number of setpoints by focusing on the biorhythm of the plant and focusing on water balance. We tested the traditional control and our new control for steering. Under the new control, it was much more consistent,” explains Peter.

Managing airflow is a key method of controlling transpiration and the crop water balance, leading to improved production and crop quality by limiting the incidence of physiological disorders and the susceptibility to disease. As Peter explains, simply considering the humidity levels in the greenhouse does not accurately present the water balance as airflow is essential to transpiration under any humidity conditions.

“If we take a leaf in an unvented greenhouse, without air flow, at 20C and 80% relative humidity and compare it to one in a greenhouse at 95% relative humidity and vented, you’ll find that more transpiration occurs under the high humidity level due the airflow disrupting the leaf boundary layer,” Peter explains.

Priva’s BioLogics principles applied through Plantonomy

Priva has been testing and developing the BioLogics cultivation method for more than ten years and has translated the principle into its newest technology, Plantonomy. Plantonomy is a cloud-based service that integrates seamlessly in the Priva platform and uses smart algorithms to monitor the crop’s biorhythm. In many cases, no additional sensors or modules are required.