Field Examinations on the Application of Novel Biochar-Based Microbial Fertilizer on Degraded Soils and Growth Response of Flue-Cured Tobacco ( Nicotiana tabacum L.).

Southwestern China is receiving excessive chemical fertilizers to meet the challenges of continuous cropping. These practices are deteriorating the soil environment and affecting tobacco ( Nicotiana tabacum L.) yield and quality adversely. A novel microbially enriched biochar-based fertilizer was synthesized using effective microorganisms, tobacco stalk biochar and basal fertilizer. A field-scale study was conducted to evaluate the yield response of tobacco grown on degraded soil amended with our novel biochar-based microbial fertilizer (BF). Four treatments of BF (0%, 1.5%, 2.5% and 5%) were applied in the contaminated field to grow tobacco. The application of BF 1.5 , BF 2.5 and BF 5.0 increased the available water contents by 9.47%, 1.18% and 2.19% compared to that with BF 0 respectively. Maximum growth of tobacco in terms of plant height and leaf area was recorded for BF 1.5 compared to BF 0 . BF 1.5 , BF 2.5 and BF 5.0 increased SPAD by 13.18-40.53%, net photosynthetic rate by 5.44-60.42%, stomatal conductance by 8.33-44.44%, instantaneous water use efficiency by 55.41-93.24% and intrinsic water use efficiency by 0.09-24.11%, while they decreased the intercellular CO 2 concentration and transpiration rate by 3.85-6.84% and 0.29-47.18% relative to BF 0 , respectively ( p < 0.05). The maximum increase in tobacco yield was recorded with BF 1.5 (23.81%) compared to that with BF 0 . The present study concludes that the application of BF 1.5 improves and restores the degraded soil by improving the hydraulic conductivity and by increasing the tobacco yield.