Abstract:

In order to improve the soil quality of tea garden, reduce the safety risk of tea and improve the quality of tea, the best microbial fertilizer and its dosage suitable for Songyang tea garden soil were explored. Soil nutrients and tea yield and quality were determined by using two kinds of microbial fertilizer, Bacillus subtilis and Bacillus glia, and different dosage control treatments. The pH value, contents of organic matter, alkali-hydrolyzed nitrogen, available phosphorus and available potassium in tea garden soil were increased by 2.44% to 3.66%, 3.01% to 8.54%, 5.36% to 9.47%, 3.66% to 7.63% and 3.38% to 13.54%, respectively. The application of bacterial fertilizer significantly reduced the content of available cadmium in soil, by 10.53% to 36.84%(P<0.05), and the application of high dosage of Bacillus subtilis fertilizer had the largest reduction of available cadmium content, by 36.84%. The contents of total nitrogen, total phosphorus, total potassium, caffeine and water extract of tea were increased by 2.03% to 12.46%, 3.57% to 17.86%, 15% to 20%, 1.78% to 8.44% and 8.78% to 47.61%, respectively. The application of bacterial fertilizer significantly reduced the cadmium content of tea leaves by 35.29% to 70.59%, and the lowest cadmium content of tea leaves applied with high dosage of Bacillus glossum fertilizer was 0.05 mg·kg^-1. Compared with low fertilizer application, the cadmium content of tea with high fertilizer application decreased significantly by 45.45%(P < 0.05). In summary, the application of the two kinds of microbial fertilizer is conducive to improving the quality of tea gardens and effectively reducing the heavy metal cadmium content in tea and soil, and the effect is more significant with the increase of the concentration of microbial fertilizer.

Key words: microbial fertilizer, tea quality, heavy metal, soil fertility