ISHS Acta Horticulturae 87: Symposium on Potential Productivity in Protected Cultivation
CO2 ENRICHMENT OF TOMATOES IN UNVENTILATED GREENHOUSES IN AN ARID CLIMATE |
| Authors: | B.A. Kimball, S.T. Mitchell |
| Abstract:
The yield of tomatoes (Lycopersicon esculentum Mill. cv. 'Tropic') was determined in CO2-enriched, unventilated greenhouses in an arid climate. The houses were cooled by recirculating the greenhouse air through water from evaporative cooling towers. The cooling system permitted CO2 enrichment of the greenhouse air for about 89% of the sunlit hours for a spring and 97% for a winter crop, as compared with 48 and 78% for a conventionally ventilated, fan-pad-cooled greenhouse. A spring crop in the conventionally ventilated house at ambient CO2 yielded 8.58 kg/plant (0.35 m2/plant), whereas in unventilated houses enriched with 650 and 1000 μl/l CO2, yields were 17 and 48% greater. In an unventilated, unenriched house, yields decreased 13%. A winter crop in the conventionally ventilated greenhouse at ambient CO2 yielded 8.48 and 9.70 kg/plant with standard and 50% more concentrated nutrient solutions, respectively. In a second ventilated house which was enriched with 1000 μl/l CO2 when the weather was cool enough to permit it, yields were 8 and 10% greater at the standard and high nutrient concentrations, respectively. In unventilated houses enriched to 1000 and 1350 μl/l, yields were 64 and 65% greater, respectively, at the standard nutrient concentration. They were 35 and 37% greater at the high nutrient concentration. | |
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