Effects of Combination of Organic and Inorganic Fertilization on the Normalized Enzyme Activity of Flue-cured Tobacco Soil under Continuing Chemical Fertilizers Reduction

Purpose To study the effects of different organic fertilizers (OF, organic fertilizer or BIO, bio-organic fertilizer) on the soil enzymes activity of flue-cured tobacco under chemical fertilizers reduction.

Method Through four years field experiment, the normalized enzyme activity was used to discuss the relationship between soil enzyme activity and the soil available nutrient and between soil enzyme activity and soil organic carbon.

Result Under 4-years chemical fertilizer 20% reduction, combined application with different organic fertilizers could increase the yield and the quality of flue-cured tobacco, the soil organic matter, soil labile organic carbon and soil enzymes activity significantly. In comparison with the conventional fertilization (CF, 100% chemical fertilizer), the activities of soil urease, alkaline phosphatase, dehydrogenase and invertase of OF treatment increased by 27.72%, 11.11%, 51.39% and 14.12%, respectively. The activities of soil urease, alkaline phosphatase, dehydrogenase and invertase of BIO treatment increased by 27.72%, 27.78%, 58.51% and 26.52% respectively. The normalized enzyme activities of OF and BIO increased by 11.88% and 19.88% respectively. The normalized enzyme activity of BIO was 7.15% higher than that of OF. Pearson correlation analysis showed that the soil normalized enzyme activity of flue-cured tobacco was extremely significantly related with soil available nutrient and soil organic carbon.

Conclusion 20% chemical fertilizer reduction combined with bio-organic fertilizer is a better practice for improving soil fertility, yield and quality of flue-cured tobacco．