Abstract: To examine the effects of nitrogen application level on the growth and nitrogen use efficiency of tea plant, we set four nitrogen fertilization treatments in the field: no nitrogen application (CK), applying pure nitrogen 16 kg·667 m^-2 (reducing nitrogen by 55.6%, treatment A), applying pure nitrogen 26 kg·667 m^-2(reducing nitrogen by 27.8%, treatment B) and applying pure nitrogen 36 kg·667 m^-2 (conventional fertilization, treatment CF). We examined the effects of different nitrogen application amounts on photosynthesis, yield, nitrogen absorption, and nitrogen use efficiency of tea plants. The results showed that treatment B promoted the chlorophyll content, net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r), but decreased the intercellular CO₂ concentration (C_i) and water use efficiency (WUE), compared to treatment CF. The yield of tea plant was the highest under treatment B, the agronomic efficiency of applied nitrogen fertilizer was the highest, the surplus of soil nutrients was less, and the efficiency of nitrogen utilization was high. The yield of tea plant was not significantly increased under treatment CF, the agronomic efficiency of applied nitrogen fertilizer was decreased, and there were more unutilized nutrients in soil. Therefore, compared with conventional fertilization, the yield of tea plant could be guaranteed and nitrogen use efficiency could be significantly improved under the condition of reducing nitrogen by 27.8%, which is beneficial to the sustainable development of tea industry.

Key words: balance of supply and demand, urban green space, green space planning., spatial equity