Tea Yield, Yield Components and Quality Response to Polyhalite As a Potash Source at the Tea.

Limited information is available in respect to the performance of polyhalite as a potash source for tea.  In an NPK balanced , replicated trial in Xishuangbanna, Yunnan, polyhalite and SOP were used as a potash source at 0, 56, 84, 12 and 168 kg K2O/ha.

The field trials in 2015 showed that, POLY4 can increase the hundred buds weight, buds density and yield of tea significantly. The effects of POLY4 on spring tea and summer tea is much better than SOP at the same K level, especially significantly better than SOP at the rational K level. As expected , potassium fertilizers application increased the yield of spring tea significantly with POLY fed crop significantly superior to SOP. The yield increased with the increasing of POLY4 rate and reached the highest yield at the recommended K level. Potassium fertilizers application increased the yield of summer and autumn tea significantly, but there were no significant differences between K source.

Application of potassium can improve the quality of the tea leaves, such as water extractable compounds, amino acid content, protein content, polyphenols content. POLY4 can increase the content of amino acid, protein and polyphenols and improve the quality at same K levels, especially at lower K levels (0.66 recommended rate) for summer tea and autumn tea.

Soil analyses post- harvest, showed no significant differences between SOP and POLY4 for pH and EC. Further there were no significant differences between SOP and POLY4 for exchangeable Ca and Mg in the soil. These results follow one year’s data, further repetitions are underway.