Hao, P.-F., Qiu, C.-W., Ding, G.,
Vincze, E., Zhang, G., Zhang, Y.
and Wu, F.
2020
Agriculture organic wastes fermentation
CO2 enrichment in greenhouse and the
fermentation residues improve growth,
yield and fruit quality in tomato.
Journal of Cleaner Production 275: 123885,
doi.org/10.1016/j.jclepro.2020.123885.
" ... the seven researchers conclude that greenhouses supplemented with CO2 via fermentation of agriculture organic wastes can (1) improve growth and (2) produce higher yields with (3) better fruit quality.
Hao et al. (2020) say tomato cultivation in greenhouses has skyrocketed in China in recent years to the point that more than half (57.2%) of all cultivation area of this important fruit occurs indoors.
... tomatoes are a significant source of a plant compound called lycopene, which reduces levels of low-density lipoprotein (LDL) cholesterol, providing cardiovascular-related health advantages to consumers.
... During the day, plant photosynthesis can reduce CO2 concentrations inside a greenhouse to around 100-250 ppm, which level is "far lower than the optimum [and can] seriously affect yield and quality."
And since cost is often a prohibitive factor in raising the CO2 concentration inside these greenhouses, researchers in China have been searching for cheap alternatives to enhance greenhouse CO2 levels to reap greater crop growth and yield.
And in the particular study of Hao et al., their solution was to install a composting device inside a greenhouse that would raise the CO2 level via fermentation of organic wastes (crop-residues and animal-manure).
... CO2 enrichment via fermentation of agriculture organic waste benefited tomato production.
As seen below, the tomato plants enriched with CO2 were larger and denser and produced bigger individual fruits.
In particular, elevated CO2 increased plant height, stem width, fruits per plant, fruit diameter, individual fruit weight and fruit yield by 39%, 29%, 74%, 28%, 29% and 29%, respectively.
... supplemental CO2 improved the overall fruit quality -- soluble sugar, soluble solids, carotenoids and lycopene were 24%, 6%, 53% and 129% higher than that observed under control conditions, while nitrate contents declined by 11% and titratable acid and vitamin C remained similar in both treatments. "
