Effect of Mixtures of Release-controlled Fertilizer and Urea on Soil Nitrogen Content in Tea Garden and Quality of Tea Leaves

Different treatments of release-controlled fertilizer and urea were conducted in tea garden,and soil alkali-hydro nitrogen content and quality components in leaves were measured.The results indicated that the alkali-hydro nitrogen content in 0~20 cm and 20~40 cm soil increased significantly under the treatments of mixtures of releas-fertilizer controlled and urea fertilizer,and a mass of alkali-hydro nitrogen could be used effectively for tea plant growth;during the six periods after the fertilizers were delivered into field,alkali-hydro nitrogen content decreased,with a rapid downtrend from the 6th to 38th d,and slowly after the 38th d,and the content of alkali-hydro nitrogen reached minimum value near the 84th d.Mixtures of release-controlled fertilizer and urea fertilizer could increase amino acid content and caffeine content in tea leaves obviously,while reduce tea polyphenols content and the ratio of polyphenols to amino acid significantly.Finally,the quality of green tea could be improved.Among the three treatments,the mixture of 30% release-controlled fertilizer and 70% urea showed the best effect.