Bamboo Biochar Pyrolyzed at Low Temperature Improves Tomato Plant Growth and Fruit Quality

As a soil amendment, biochar can significantly improve soil quality and crop growth. Few studies, however, have explored biochar effects on crop quality. This study investigated the amendment effects of bamboo biochar pyrolyzed at different temperatures on plant growth and fruit quality of tomato (Solanum lycopersicum L.). Tomato ‘Micro-Tom’ plants were grown in a sand medium amended with 0, 1, and 3% of biochars produced at 300 °C, 450 °C, and 600 °C, respectively. Plant growth was monitored, and fruit harvested at the red stage was analyzed for color, texture, soluble solids content, sugars, ascorbic acid, and acidity. Results showed that biochars produced at 300 °C and amended at 3% or pyrolyzed at 450 °C and amended at 1% increased plant growth index. Contents of glucose, fructose, soluble solids, ascorbic acid, and sugar-to-acid ratios of fruits produced from the two treatments were significantly higher than the other treatments. The improved plant growth and fruit quality were related to the higher concentrations of NO3, P, Ca, and Mg in the growing media. Our results suggest that optimizing biochar use can be achieved by targeting biochar production conditions and application rate, which resulted in desirable amendment and fruit quality effects