Efficiency of application of meso and microfertilizers on tea plantations in the Russian subtropics

The economic efficiency of using macro (NPK) and micronutrient fertilizers (Mg, Ca, B, Zn) in full-grown tea plants (Camellia sinesis (L.) O. Kuntze) has been studied in a long field experiment in the conditions of the Black Sea coast of Sochi. According to generalized data for the period 2011-2015 it has been shown that the use of boron, a mixture of elements (Zn + B + Mg), and options with the addition of calcium and zinc in favorable weather conditions have led to an increase in productivity by 35, 22 and 17%, respectively. The increase in productivity has increased profits by 80-180 thousand rubles. The positive effect of the introduction of magnesium manifested in the first years of the experiment, is no longer observed.The cost of introducing only meso and micronutrient fertilizers ranged from 0.45 to 22.0 % of the amount of additional production costs. The analysis of economic efficiency has shown that the use of fertilizers in tea growing is beneficial, since the level of profitability on all options exceeds 25%, and the use of boron and a mixture of elements increases the profitability of production to 37-38 %, which is a significant value for the tea industry.