Abstract: Aims Over a year, Rushan tea is booming gradually, but due to the low temperature in winter and early spring, the areas for tea plantation has been decreasing year by year. Therefore, how to achieve a higher yield at lower cost has become a major issue in the test plantation area. The paper examined the characteristics of microclimate in four shelterbelt systems of tea garden in order to identify a suitable forest-tea system in the study area.Methods The tea plantation studied was established in the spring of 2007 with terrace soil preparations, involving four forest shelterbelt grid systems (i.e. 8 m × 80 m, 12 m × 80 m, 20 m × 80 m and 40 m × 80 m). The wind speed, air temperature, soil temperature, relative air humidity and relative soil moisture were measured in the four shelterbelt systems in April, August and December of 2013, with the tea plantation without shelterbelt as control. Important findings Firstly, the four shelterbelt systems all reduced wind speed effectively, increased air relative humidity, regulated air temperature, soil temperature and soil relative moisture, and improved ecological environment in favor of tea production. Secondly, due to the seasonal variations of regional water flux and solar radiation, the regulation effects of the four shelterbelt systems differed. Thirdly, the results of principal component analysis showed that, the main factors inducing different microclimate characteristics were the air temperature and soil temperature, with factor loads of -0.978 and 0.986, respectively. The wind speed and air temperature showed a highly significant correlation, but there was no significant linear relationship between wind speed and soil temperature, indicating that wind speed could affect the microclimate indirectly. Overall, the shelterbelt system of 8 m × 80 m is better than the other three systems in the effects of regulating microclimate.

Key words: humidity, microclimate, northern tea garden, protection forest, temperature, wind speed