Concentrations of CO2 are commonly suboptimal for plant production in greenhouses. A new strategy using crop residues and animal manure (CRAM) composting was developed to increase CO2 concentration within greenhouses used for vegetable production. During the whole cultivation period, the CO2 concentrations in the CRAM composting treated greenhouses increased by more than 100% of that in the control greenhouses. Greenhouses containing CRAM composting units produced yields of celery (Apium graveolens L.), leaf lettuce (Lactuca virosa L.), stem lettuce (Lactvca saiva L.), oily sowthistle (Sonchus oleraceus L.) and Chinese cabbage (Brassica Chinensis L.) that were 270%, 257%, 87%, 140% and 227% higher, respectively, than those in control greenhouses. The effect that the presence of CRAM composting had on several vegetable quality parameters was also examined. Nitrate concentrations deceased in celery, leaf lettuce, oily sowthistle and Chinese cabbage by 8%, 36%, 30% and 20%, respectively. The concentrations of soluble sugars in oily sowthistle and Chinese cabbage were also significantly increased by the composting procedure. In addition, the ascorbic acid contents increased in all five species, with average increases of 13%, 39%, 25%, 72% and 37% for celery, leaf lettuce, stem lettuce, oily sowthistle and Chinese cabbage, respectively. It is concluded that CO2-fertilisation using CRAM composting in greenhouses increases yields and improves quality of common vegetables.
Jin, C., Shaoting, D., Wang, Y., Condon, J., Lin, X., & Zhang, Y. (2009). Carbon Dioxide enrichment by composting in greenhouses and its effect on vegetable production. Journal of Plant Nutrition and Soil Science, 172(20039), 418-424. https://doi.org/10.1002/jpln.200700220