Soil nitrogen status in Tieguanyin tea plantation of Fujian Province

An investigation on the content and availability of nitrogen in surface soil and corresponding nitrogen concentration in tea leaf was conducted in 14 major Tieguanyin tea-producing areas in Anxi, Yongchun and Hua’an Counties of Fujian Province. The objective of the research was to determine N supply capacity of soil of Tieguanyin tea plantation in Fujian Province. To that end, 150 surface soil samples and corresponding tea leaves were collected and analyzed. The results show that total soil N is medium to low with an average of 0.79 g·kg^-1. Alkali-hydrolysis N is medium to high with an average of 95.56 mg·kg^-1. Total soil N is significantly correlated with alkali-hydrolysis N. Organic matter content and CEC have significant correlations with both total and alkali-hydrolysis N. Total soil N content also depends on the parent soil, and decreases in the following order: paddy rice soil > yellow soil > red soil > yellowish red soil > lateritic red soil. Soil with higher clay content contains higher total N. N concentration in tea leaf ranges from 8.1~141.8 g·kg^-1, with an average of 23.7 g·kg^-1. No significant correlation exists between tea-leaf N and soil alkali-hydrolysis N. The use of alkali-hydrolysis N as a source of soil nitrogen and tea-leaf N concentration index to monitor N deficiency in tea plants is subject to further research. More organic manure is required for the tea plantations in Fujian Province. It is important to avoid over application of N fertilizer.