Effect of Long-term Compound Additives on Tea Plants

A 2-year field experiment was conducted to study the effect of the long-term compound additives (NAM) in varying quantities on the tea trees. The results showed that increased NAM caused gradual increase on NH4+-N and reduction on NO3--N. The additive slowed down the conversion of NH4+-N to NO3--N. With the additon of NAM, tea yield was increased initially, and then, decreased. Both yield and hundred-bud-weight of green tea peaked when 75% NAM was applied. The yield was more than 5.20% in 2010, and 2.64% in 2009, as compared to the control. The increasing rates on tea yield, bud density and hundred-bud-weight were higher in 2010 than 2009. And, the NH4+-N and NO3--N contents in the soil were also higher in 2010 than 2009. Thus, it was concluded that NAM application could inhibit urea hydrolysis and ammonium nitrification resulting in savings on labor fertilizer.