Effects of a controlled-release nitrogen fertilizer on tea yield and quality and rational application technology

Rational application of controlled-release N fertilizer plays a significant role in increasing nutrient use efficiency,tea yield and quality.Field trials with different application quantities and times were conducted to study the effects of a controlled-release nitrogen fertilizer on tea and rational application technology.The results showed that the controlled-release nitrogen fertilizer could significantly extend its release time in the soil,and keep higher NH4+-N concentration for longer time,but the NO3--N concentration was not significantly different from that of urea,resulting in low ratio of NO3--N to total inorganic N.The nitrogen release characteristics of the controlled-release nitrogen fertilizer could basically match the N requirement of tea plants.The application of the controlled-release N fertilizer significantly increased N concentration in tea shoots,improved the absorption of K and Zn,and increased chlorophyll concentration in leaves compared with urea.The controlled-release nitrogen fertilizer rate could be reduced by at least 30% without affecting tea yield and quality.With same amount of N(600 kg/ha),controlled-release N application increased tea yield by 6.6% ～ 24.1% with an average of 12.9%,as well as tea quality components,especially free amino acids in tea shoots.