Purpose To explore the effects of biochar combined with soil improver on acid soil in Xiajiang tobacco-growing area and its influence on the growth, development and quality of flue-cured tobacco.
Methods Field experiments were conducted to study the effects of four soil improvers (sodium carboxymethyl cellulose, seaweed fertilizer, chitin, and seaweed chitin refined potassium) combined with biochar on soil pH, nutrients, enzyme activity and yield and quality of flue-cured tobacco.
Results Compared with the control, the combined application of biochar and four soil improvers increased soil pH by 4.09%-10.76%, 2.13%-9.25%, 0.69%-5.79%, and 1.04%-12.02%, respectively. Combined application of seaweed chitin refined potassium increased soil organic matter and available potassium by 17.35%-21.19% and 28.46%-40.80%, respectively. All treatments improved sucrase activity in rhizosphere soil to varying degrees, and the urease activity in soil with chitin was the highest, with an increase of 20.57%-31.16%. The maximum leaf area increased significantly by 7.01%-17.71% with the application of seaweed chitin refined potassium; under this treatment, comparing with the control, the physical property index, chemical availability index, and neutral aroma substances content of flue-cured tobacco were the highest, which were increased by 6.25%, 39.65%, and 56.15%, respectively; the yield, output value, proportion of superior leaves, proportion of middle and superior leaves, and average price increased by 8.49%, 15.99%, 14.32%, 10.36%, and 6.89%, respectively.
Conclusion All four soil improvers can improve the soil characteristics. Among them, the combined application of biochar and seaweed chitin refined potassium can obviously improve the acid tobacco-growing soil, effectively promote the growth of tobacco leaves, improve the quality of tobacco leaves and increase economic benefits, and the effect is better than that of other soil improvers combined with biochar.
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