Characteristics of soil nutrients, heavy metals and tea quality in different intercropping patterns

Intercropping is an important agroforestry practice that can not only increase biodiversity, improve microenvironment and resource utilization, but also improve crop yield and quality. In this paper, the soil environmental characteristics and tea quality of three tea-fruit intercropping patterns (loquat-tea, waxberry-tea, and citrus-tea) and pure tea garden were studied. The soil samples of 0–10 cm, 10–20 cm and 20–30 cm depths in different seasons (spring and autumn) were collected to analyze the physicochemical characteristics of the soil. Corresponding tea bud samples in spring were collected for the determination of the main chemical components. The soil nutrient of the three intercropping patterns was higher than that of the single tea plantation, while the heavy metal content and pH value were opposite. Moreover, the difference in soil nutrient and pH under intercropping patterns were correlated with the sampling period. The tea plantation under intercropping patterns had higher free amino acid content, lower catechins content and the ratio of phenol to amino acids, which is conducive to the formation of green tea quality. Under the patterns of loquat-tea intercropping and citrus-tea intercropping, soil nutrients were higher than that of waxberry-tea intercropping. For the tea plantation soil heavy metals, waxberry-tea intercropping and citrus-tea intercropping had lower concentration than that of loquat-tea intercropping. However, citrus-tea intercropping is superior to the other two intercropping patterns for tea quality. These results may enhance the understanding of tea-fruit intercropping patterns for improving the soil environment of tea plantation and the quality of tea.