Effect of Biochar and Compost Addition on Mitigating Salinity Stress and Improving Fruit Quality of Tomato

To overcome food security, sustainable strategies for reclamation and the subsequent utilization of salt-affected soils for crop production are needed. The aim of the current study was to evaluate the impacts of compost and biochar addition on the growth and fruit quality of tomato under salinity stress. For this purpose, the soil was spiked with analytical grade sodium chloride to achieve a 6 dS m-1 salinity level for a pot experiment. After 30 days of spiking, the compost (2%) and biochar (2%) were added in selected pots. After the seedling transplant, recommended doses of NPK were added to fulfill nutrient requirements of tomato plants. Plants were harvested after 90 days of seedling transplantation. Results revealed that the salinity caused a significant reduction of 28.4% in SPAD value, 23.5% in Ft, 22.6% in MSI, 12.1% in RWC, 18.3% in Chl. a, 13.7% in Chl. b, and 16.5% in T. Chl. as compared to the un-amended non-saline control in physiological attributes of tomato plants. Similarly, a significant decrease of 26.9-44.1% was obtained in growth attributes of tomato as compared to the non-saline control. However, in saline soil, the addition of biochar and compost (alone or together) demonstrated a significant improvement in plant growth (i.e., up 45%) over the respective un-amended control. Moreover, the combined application of compost and biochar significantly reduced the sodium (Na+) in shoots and roots of tomato plants by 40% and 47%, respectively, over the respective control. Our findings suggest that the combined application of biochar and compost could be useful to reduce salinity, alleviate salinity-induced phytotoxicity, and subsequently improve plant growth and productivity in salt-affected soil.