Since the summer of 2023 , Wageningen University & Research has been direct a trial with reverse air circulation in genus Gerbera cultivation . An altered AVS - C installation from Van Dijk Heating facilitates the cognitive process in which dry air is blown in above the crop . Underneath the cultivation gutters are pipes with golf hole , which extract moist air from the greenhouse . The downward ironic melody watercourse reduces the hazard of transpiration wet condense on the prime , which is a cause of caliber issues .
repel by high get-up-and-go damage , many cultivator have traded their HPS lamp for more effective LED installment in recent year . But these utter less radiant heating plant . Many have also lower their heat and inflammation stimulus to cut costs . The downside of these understandable natural process is that in the early morning , when the crop temperature is still low-pitched , wet condenses on parts of the craw more often . Then wet - know kingdom Fungi , such as Botrytis , have a better luck of infect crop . " Many gerbera growers have struggled with this and still do , " says researcher Frank Kempkes . " A Botrytis blight in the heyday can have what is called ' crown rot , ' which makes the bloom despicable . It ’s a moisture - related problem . "
Kas als EnergiebronWith funding from the Kas als Energiebron ( Greenhouse as an Energy Source ) programme , a trial was set up last class as part of the Greenhouse 2030 projection to put on more insight into the problem and potential solutions for better moisture ascendancy . In a mid - full term rating with Ton van Dijk , who is involve in the project on behalf of Van Dijk Heating , Kempkes and his colleague Tom Baeten explain what they have instruct so far .
tribulation in two compartmentsThe trial compares the common airwave discourse with AVS - C , in which conditioned air is acquaint under the harvest and extracted above the crop , to turn breeze circulation . For this intent , a subdivision of the Greenhouse 2030 manifestation glasshouse has been divided into two compartment using foil . In both compartments , there are adequate numbers of growing sewer and the plant varieties Kimsey and Love Me . consider gutter , mood box , thermal imaging cameras , and sensor are used to learn about relevant parameters , including flower and leaf temperature and instant transpiration by the crop .
Standard and convert AVS - CIn the reference compartment , the air treated with an AVS - C building block is gasconade out from under the growing gutter via the common distribution hoses . Moist nursery airwave is pass in via a suction duct on the outside bulwark , which is connected to the AVS - C unit . As common , the cooling occlusion to condense the moisture that is drawn in is located at the top of the unit . In the reborn AVS - C social unit that operates the " converse " compartment , the cooling engine block is at the bottom of the installment , and the heating cylinder block is at the top . " That is the most logical positioning if the moist melodic line is being quarter in from below and the heated air has to be blow out at the top , " explain Ton van Dijk . Kempkes add : " For effective dehumidification , it is important for the strain to be draw through the harvest . When you mess up out dry melody from under the crop and draw in moist air above the crop , it moves up along and through the craw absorbing transpiration moisture in the cognitive operation . This mean the most humid air reaches the flower . To go in the opposite instruction , we wanted to pull the breeze equally through the crop . For this , we placed large - diam perforated PVC pipes under the growing gutters . Without that frame-up , the desired direction of airflow would not be achieved . "
Frank Kempkes
Warmer flowers , dryer airThe readings show that the air temperature in the reversed compartment is eminent on modal than in the adjacent compartment using the traditional bottom - up circulation . " Which makes sense , because the flowers turn out above the canopy and are settle just below the incoming ironical air watercourse , " explains Tom Baeten . " Since that air is relatively juiceless , the luck the efflorescence will have moisture problem is also trim . "
Less crown rotThe central head , of course , is whether that has also meant less crown rot . In Greenhouse 2030 , several visitation field have been set aside where various things are valuate and recorded twice a workweek , including the phone number of rotten flower head . Indeed , the data point collected showed that significantly fewer rotted blossom heads occurred in the " reversed " compartment than in the traditional compartment . This seems to support the hypothesis that the crown rot is make by wet problem .
Unexplained differencesIt is striking that there is much better dehumidification in the " reversed " compartment , namely around 22 guanine / m2 / hour versus 14 g / m2 / hour in the standard compartment during the benighted hours . Baeten : " That ’s more than half as much , while the weighing gutters point that the plant transpire like a shot at night and even somewhat less in the ' reversed ' compartment during the twenty-four hours . " " We ca n’t explicate that difference yet , " Kempkes recognize . " We require to be able to put our digit on that and are therefore going to install more sensors . By measuring more , and more accurately , we hope to discover an account . " The researchers ' preliminary conclusion is that the nursery climate and moisture balance can indeed be positively touch by rearward air circulation . " With the caveat that we ’re also encountering surprise that we ca n’t yet explain properly , this seems to be a direction that merit further exploration . "
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