The use of drip fertigation to reduce fertilizer pollution of the Danjiangkou Reservoir of China was explored. Specifically, a 4-year experiment was conducted to identify the optimum fertilizer rate for fertigation of a tea plantation. The treatments included five fertigation levels, 10 % (10 % NPK), 20 % (20 % NPK), 30 % (30 % NPK), 40 % (40 % NPK) and 50 % (50 % NPK) of the traditional fertilizer dose, and the traditional fertilizer dose under rain-fed conditions as a control (CK). Relative to CK, fertigation treatments decreased total nitrogen (TN), total phosphorus (TP) runoff loss (kg ha-1) and TN and TP concentrations (mg kg-1) in leaching water by 51.9-70.8, 51.7-67.5, 56.1-85.4, and 39.1-56.5 %, respectively. Total N, TP runoff loss and TN concentrations in leaching water generally increased with increasing fertilization rate among fertigation treatments; however, there was no significant difference in TP concentrations of leaching water. Yield increased with increasing rate of fertilization among fertigation treatments. The yields of the 30-50 % NPK treatments were similar (P > 0.05), but higher (P < 0.05) than those of the 10-20 % NPK treatments. There were no significant differences in yield among the 30 % NPK, 40 % NPK and CK treatments. The relative yields increased rapidly when the relative fertilizer rate was between 10 and 33 %; however, this increase slowed at fertilization rates above 33 %. Based on the yield and fertilizer pollution control, fertigation with 33 % of the traditional fertilizer dose should be considered for tea production in the water source area.
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Acknowledgments This study was supported by the project of the Research Center for Policy and Technology, Office of the South-to-North Water Diversion Project Commission of the State Council, and the Important Orientation of Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-359).
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- Drip fertigation
- Total nitrogen loss
- Total phosphorus loss