In week 38 bell pepper plants from the variety Mavera have been planted in two test greenhouses of the Improvement Centre in Bleiswijk. One greenhouse with hybrid lighting (SON-T + LED) and one greenhouse with 100% LED. The research is being conducted by Delphy Improvement Centre and Plant Lighting and is being closely monitored by bell pepper growers and cultivation advisers.
Bell peppers are hardly grown year round in The Netherlands. Growing year round has advantages for the market, but also a number of challenges. In the past results of tests with lighted bell pepper growth were mixed, with sometimes difficult fructification and insufficient stretching of the bud. By combining cultivation knowledge (Delphi and growers), plant physiological support (Plant Lighting) and light knowledge (Signify), we hope to realize successful year round cultivation.
The basis of the research is that the quantity of assimilates are being produced by the variety in balance with the demand for assimilates by the developing fruits. In a regular unlighted cultivation, daylight and plant taxation increase simultaneously. In the lighted test the results are exactly reversed: shortly after planting there is lots of daylight and little need for assimilates. The plant tends to produce lots of fruits. Then the plant taxation will increase, and also the demand for assimilates, but daylight is diminishing. The hypothesis is that a too large plant taxation in the beginning will lead to imbalance-related problems later on.
That is the reason why plant taxation is built up according to a tight schedule, and any overage of fruits is immediate cut away. The lighting is geared as much as possible to the shortage of daylight to meet the assimilate demand. Aided by photosynthesis measurements and crop models the assimilation of the crop is calculated as precise as possible. Furthermore, part of the crops are being used for experiments with directional light to measure the effect on stretching in the bud.
The crop is looking healthy now, and the first fruits have set. The goal is to end up with around 40 kg production. It will be exciting how the growth will proceed around the shortest day and in the following period.
The program Kas als Energiebron, Signify, and crop cooperation Paprika financed the research.
Source: Kas als Energiebron