Effects of Combined Application of Rapeseed Cake and Chemical Fertilizers on Nutrients, Enzyme Activity of Tobacco Growing Soil and Nitrogen Utilization

In order to find out the suitable fertilization methods and improve the soil fertility and nitrogen utilization of flue-cured tobacco in tobacco planting areas of Liangshan, Sichuan, field experiments were conducted to study the effects of combined application of rapeseed cake and chemical fertilizer on tobacco growing soil nutrients, enzyme activities and nitrogen utilization under same nitrogen conditions. The results showed that rapeseed cake fertilizer nitrogen replacement 30% chemical fertilizer nitrogen treatment significantly increased the contents of total organic carbon, dissolved organic carbon, available phosphorus, available potassium and soil urease activity; significantly decreased soil pH, activities of soil peroxidase and polyphenol oxidase in flue-cured tobacco mature stage. Pearson correlation analysis showed that the activities of soil peroxidase and polyphenol oxidase were negatively correlated with dissolved organic carbon, soil polyphenol oxidase activity was significantly positively correlated with NO₃^--N content, soil peroxidase activity was significantly positively correlated with NH₄⁺-N content. soil urease activity was significant positively correlated with soil carbon, available phosphorus, available potassium and carbon nitrogen ratio, but significant negatively correlated with soil pH. rapeseed cake fertilizer nitrogen replacement 30% chemical fertilizer nitrogen treatment significantly improved flue-cured tobacco dry matter accumulation, nitrogen content, nitrogen accumulation and nitrogen utilization rate in the mature stage. The replacement of 30% chemical fertilizer nitrogen by rapeseed cake fertilizer is a suitable fertilization method to improve soil fertility and increase the growth of flue-cured tobacco and nitrogen utilization.