Effect of Soil Conditioners on Physical and Chemical Characteristics of Soil and Yield and Quality of Tea

To modify the physical and chemical properties of the soil and to improve the yield and quality of the tea, a field trial on two soil conditioners (i.e., humic acid and weathered coal) was conducted.The conditioners were added to the soil at a tea plantation with a balanced use of nitrogenous, phosphorus and potassium fertilizer for the previous 3years.The results showed that the weight/volume of the soil was reduced by 7.22%-15.44%;the porosity, pH, organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzable nitrogen, available phosphorus and potassium of the soil increased by 8.24%-18.62%, 2.97%-18.61%, 8.86%-27.22%, 9.80%-45.10%, 6.12%-40.82%, 4.52%-40.16%, 8.81%-45.75%, 0.62%-67.55% and5.56%-36.09%, respectively;and, the yield and polyphenol content of the tea increased by 3.19%-14.24%and5.21%-10.73%, respectively.Specifically, the application of the " chemical fertilizer+humic acid+weathered coal" showed the most significant effect on increasing the yield and polyphenols of the tea and the alkali-hydrolyzable nitrogen content in the soil.The application of the " chemical fertilizer+humic acid" appeared to be most significant in bringing about the decrease on the volume-weight and increases on the porosity, organic matter, total nitrogen, total phosphorus, total potassium, available phosphorus and potassium of the soil.And, the treatment with the "chemical fertilizer+weathered coal" was most effective in raising the pH of the soil.