Influence of multi-timescale precipitation indices on primary tea production in Baoshan, Yunnan, China

Abstract

The regional economy in Yunnan, Southwest China, relies heavily on tea production. Both the quality and amount of tea production are sensitive to extreme climate events, but exactly how different timescale climate events influence tea production remains unknown. In this study, we explore the dynamic responses of tea production indices in Baoshan, Yunnan to 6 multi-timescale precipitation indices (MPIs) at lags of up to 20 years. The results are as follows: (1) Wet injury caused by precipitation during summer and autumn is a prominent threat to annual tea production in Baoshan, which leads to negative impacts on annual tea yield and raw tea price, with the impact on the latter mainly reflected in tea quality during the primary processing for black tea and green tea. (2) Annual tea yield and raw tea price are negatively correlated with CDD (consecutive dry days) and R20 (very heavy precipitation days) at lags greater than one year. (3) Spring tea yield and raw tea price are negatively correlated with spring precipitation, but positively correlated with days in the winter-spring dormancy period of tea plant (WSDP) and precipitation in WSDP; the positive correlation of days in WSDP is the most prominent with spring tea production of the 3 MPIs. (4) Unlike other famous tea areas, lower R20 frequency in Baoshan is not associated with high rates of soil erosion, but the lack of drainage ditches in the tea garden still means that continuous precipitation or heavy rainfall are a risk to Baoshan tea production. The insights provided by this study will help farmers and other decision-makers to understand the mechanism of MPIs' influence on tea production, inform regional responses in tea plantation management to the observed different precipitation trends, and improve future management decisions under a changing climate.