Effects of Light Intensity, Water Content, and the Application of Biochar Nanoparticles on the Growth and Development of Tomato Seedlings

Abstract

This study investigates the effects of light intensity, water content, and the application of biochar nanoparticles (BNPs) on the growth and development of tomato seedlings to provide valuable insight into tomato cultivation. BNPs were prepared using rice straw. In this experiment, the light intensity was set at 350 μmol ·m−2 · s−1 (L1), 300 μmol ·m−2 · s−1 (L2), and 250 μmol ·m−2 · s−1 (L3). The irrigation amount was set at 150 mL/plant (W1) and 100 mL/plant (W2). The contents of BNPs were set at 0% BNPs (N1) and 5% BNPs (N2). L2W2N2 was used as the control. A total of 12 groups were included in the study. Groups D, E, F, J, K, and L did not use BNPs, while the remaining six groups used 5% BNPs. We found that BNPs exhibit significant aggregation with spherical morphology. As the pH increased, the particle size of BNPs showed a trend of initial increase, followed by a decrease and subsequent increase. Carbon elements existed in three different forms and possessed distinct chemical bonds, resulting in different relative contents. The relative content of C═O accounted for 26.40%, which was significantly higher than that of C—O by approximately 15%. Under the W1 treatment, the height of the tomato plant in L1N2 was 31.7 cm, which is higher by 0.4 cm than that in L1N1. Under L2W1N1 treatment, the net photosynthetic rate, transpiration rate, stomatal conductivity, and intercellular CO2 concentration of tomatoes were 9.68 μmoL ·m2 · s−1, 1.223 mmoL ·m2 · s−1, 0.071 μmoL ·m2 · s−1, and 626 ppm, respectively, which are significantly higher than the control. In conclusion, this research provides a foundation for growing tomatoes.