Economic and ecological efficiencies of tea plantations under different cultivation models

Objectives Investigating the effects of management models on soil fertility and the economic benefit of tea plantations can provide a scientific guidance for optimizing the management and green development of tea plantations in the agricultural industry.

Methods This study was conducted in Zhejiang Province in 2012. The four tea plantation models surveyed were pure tea (CK), planting grass between tea trees (GT), cultivating mushroom under tea trees (BT), and raising meat chickens in tea garden (PT). All the four models have existed for 10 years. Tea yield, income, and expenditure from 2019 to 2021 were investigated. Soil samples at 0−20 cm, 20−40 cm, and 40−60 cm depth were collected in 2021 to determine pH, soil organic matter (SOM), total and available nutrient contents. The comprehensive soil fertility was evaluated by Fuzzy Comprehensive Evaluation Method.

Results Compared with CK, GT, PT, and BT increased the average tea yield by 63.5%, 79.4%, and 99.2% and enhanced the net income by 66.7%, 99.7%, and 83.7%, respectively. Black fungus and free-walking chicken in BT and PT models contributed additional income of 40.9% and 22.1%, respectively. The ratio of income to investment in CK, GT, PT, and BT models was 2.57, 3.23, 3.69, and 2.51, respectively. GT and PT had higher income and investment ratio while BT recorded similar value to CK. During 10 years experiment, soil pH at 0−20 cm in the CK decreased from 4.23 to 3.69, while in GT, PT, and BT increased to 6.93, 4.55 and 5.41, respectively, alleviating soil acidification. Compared with CK, SOM at 0−20 cm soil depth did not change in GT, PT, and BT. However, SOM at 20−40 cm and 40−60 cm depth increased in GT, PT, and BT, respectively. Overall, SOM in GT, PT, and BT were significantly increased by 39.5%, 21.8%, and 7.54%, respectively at the depth of 0−60 cm. Compared with CK, 0−20 cm soil fertility index in the GT, PT, and BT increased by 77.6%, 68.3%, and 44.8%, respectively, and the effect of GT and PT models was better than BT. Under CK model, NH₄⁺-N and NO₃⁻-N content was higher in 40−60 cm soil than 0−20 cm depth, which were 1.58 and 2.57 times of those in the surface soil.

Conclusions All the three multiple tea plantation models showed higher merits than the pure traditional tea plantation, despite differences in their economic and ecological benefits. Tea-mushroom and tea-chicken plantation had higher tea yield and generated extra income through the sale of chicken and mushroom. The tea-chicken model had the highest production-investment ratio; grass-tea plantation showed higher efficiency in alleviating soil acidification, improved soil fertility, and reduced the risk of N leaching.