Effects of maize straw biochar application on soil physical properties, morph-physiological attributes, yield and water use efficiency of greenhouse tomato

Tomato (Solanum lycopersicum L.) production was threatened by the inefficiency of fertilizers, contributing to the deterioration of the soil environment under greenhouse conditions in southern China. Biochar application could ameliorate the physical properties of soil and enhance the growth and productivity of tomatoes. In this study, a pot experiment was conducted with four biochar addition rates of 0% (BA₀), 1% (BA₁), 3% (BA₃), and 5% (BA₅). Results showed that the soil physical properties, morph-physiological indicators, yield, and water use efficiency (WUE) of tomatoes with biochar addition were significantly higher than those of tomatoes without biochar addition. Among the different treatments, BA₅ provided the highest total porosity (53.09%), field capacity (40.73%), plant height (72.5 cm), net photosynthetic rate (16.04 mmol/m²·s), total dry matter (184.65 g/plant), yield (54.9 t/hm²), and WUE (38.5 kg/m³). The yield and WUE increased from 44.5 t/hm² and 31.2 kg/m³ under BA₀, respectively, to 54.9 t/hm² and 38.5 kg/m³ under BA₅, respectively. The results suggest that BA₅ can maximize improvements in soil physical properties to augment plant growth, thereby increasing the yield and WUE of tomatoes. However, the effects of BA₃ and BA₅ on WUE were not significantly different. Thus, from the perspective of economic investment, BA₃ is recommended.