Tea (Camellia sinensis) is an important cash crop and the most widely consumed beverage in the world. The global tea industry, particularly the booming Pu'er market, has increasingly relied on converting forests to monoculture plantations for higher productivity. This has raised alarms over soil degradation, biodiversity loss, and deteriorating tea quality.
Recently, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences identified the optimal balance between forest coverage and planting density to boost tea quality and soil health. They demonstrated that integrating medium tea planting density with medium-coverage forests significantly enhances tea quality, improves soil nutrients, and creates a better microclimate. The findings were published in Agriculture, Ecosystems and Environment.
Researchers conducted this study in Xishuangbanna, Yunnan Province, China. They selected three habitat types: monoculture (T1), medium-coverage tropical evergreen broad-leaved forest (T2), and high-coverage forest (T3), and two tea planting densities: medium (M) and high (H). They thoroughly investigated the effects of various habitats and tea planting densities on microclimate, soil nutrients, tea nutrients, growth, and quality.
Among different combinations of the habitat type and the planting density, researchers found that the combination of medium-coverage forest and medium tea planting density (T2+M) consistently delivered the best outcomes. T2+M improved microclimatic conditions of tea plants by increasing the relative humidity and soil moisture while reducing the light intensity, soil and air temperatures. It also significantly boosted soil nutrients across all layers, increasing total nitrogen, available phosphorus, and available potassium.
Moreover, researchers revealed that the T2+M treatment improved tea nutrients and quality. Tea plants in T2+M exhibited higher chlorophyll content, and significantly increased levels of essential nutrients in young shoots and mature leaves. Crucially, T2+M tea contained dramatically higher levels of key quality compounds: amino acids and catechins, which are vital for tea flavor and health benefits. Medium tea density consistently outperformed high density across tea nutrients, growth, and quality metrics.
"Integrating tea within medium-coverage forests at moderate density is optimal for high-quality tea production. It produces higher quality tea, combats soil degradation, and supports biodiversity, which offers practical solutions for farmers and strong evidence for policymakers to promote agroforestry in the tea sector," said SONG Liang from XTBG.
