The benefits of carbon dioxide enrichment have been well documented for a number of greenhouse crops, with the overall impact being accelerated growth and biomass accumulation. For most growers, adding supplemental carbon dioxide is done by burning natural gas or using compressed liquid carbon dioxide, the latter requiring vaporizer units to deliver the carbon dioxide as a gas into the grow area atmosphere. Despite its clear benefits to production, carbon dioxide enrichment can be antagonized by greenhouse venting, which essentially provides a highway for the carbon dioxide out of the greenhouse.
This is especially true for greenhouses below 40° N and above 40° S, whose climates often require significant venting in the summer, according to Aaron Archibald, VP of Sales & Strategic Alliances at CO2 GRO. The precision agtech company provides greenhouse growers with aqueous carbon dioxide solution technology, wherein the carbon dioxide is dissolved in water and applied to the leaves.
Aside from directly improving crop productivity, CO2 GRO has also studied the potential of dissolved carbon dioxide to suppress the development of pathogens such as E. coli and powdery mildew. "This makes CO2 GRO's technology an even better fit for organic growers whose list of approved chemicals is quite restricted", says Aaron.
Aqueous CO2 is essential in tropical climates
According to Rodrigo Martínez Alvarez, general manager at Hidroexpo, CO2 GRO's unique aqueous carbon dioxide enrichment technology is practically the only way that South and Central American growers can efficiently use CO2 enrichment in their greenhouse. Hidroexpo is a pepper greenhouse located in La Libertad, El Salvador. Due to the high venting requirements in tropical climates, using gaseous CO2 enrichment in the greenhouse atmosphere was unfeasible as it would simply be blowing the gas out of the vents. With CO2 GRO's aqueous enrichment technology, carbon dioxide is applied directly to the leaves, allowing the greenhouse to vent as required without losing the photosynthesis-driving gas.
"At Hidroexpo, we didn't have experience with gaseous carbon dioxide because of our venting requirements – we would lose 70% of the carbon dioxide simply because we need to vent. With CO2 GRO, we are trying to find out how to use supplemental carbon dioxide most effectively in El Salvador," says Rodrigo.
Hidroexpo has been using CO2 GRO for three years, conducting different trials to learn how the technology works and how the crop responds. At first, CO2 GRO was installed in 0.5 hectares of a 1-hectare greenhouse, allowing Hidroexpo to compare the productivity of their crop with and without carbon dioxide enrichment. Since then, Hidroexpo has installed CO2 GRO in two 1-hectare greenhouses and is evaluating different operating strategies between the greenhouses in order to further optimize the technology's benefits.
"In agriculture, you don't have a formula or one-size-fits-all. You have to try things to learn how to get the best results. We've been learning the amount of carbon dioxide to be used, how often to apply, etc.," Rodrigo explains.
Since implementing CO2 GRO, Hidroexpo has seen improved yields and stronger plants, with every new trial producing a better crop. To any growers considering CO2 GRO's technology in their greenhouse, Rodrigo recommends running thorough trials with the new technology to learn exactly how to use it and what parameters work best for their greenhouse.
For more information:
Aaron Archibald, VP of Sales & Strategic Alliances