Optimizing tea plantation productivity: Magnesium-modified tea pruning litter biochar enhances soil quality and tea aroma profiles
Wenbin Liu, Yubo Luo, Xiangzhen Zhu, Dubin Dong, Mei Wang, Jiawei Ma, Zhengqian Ye, Dan Liu
Abstract
Soil acidification and magnesium (Mg) deficiency severely limit tea productivity and quality. This study investigated the potential of Mg-modified biochar, derived from tea pruning waste, to remediate acidic soils and enhance tea plant performance. A 90-day pot experiment was conducted with four treatments: control (CK), Mg sulfate fertilizer (FC), tea pruning litter biochar (BC), and Mg-modified tea pruning litter biochar (BCY). The study evaluated the effects on soil chemical properties (pH, nutrients, cations), plant growth parameters, and tea quality indicators, including biochemical and aroma profiles. Both BC and BCY significantly increased soil pH by 0.27–0.39 units ( p < 0.05). Among treatments, BCY showed the most pronounced effects, improving soil organic matter (22.93 g kg −1 ), available phosphorus (by 84 %), cation exchange capacity (by 76 %), and Mg 2+ (by 519 %) levels, while reducing Al 3+ and H + concentrations by 59 %. In addition, BCY enhanced microbial activity and carbon (C) metabolism. Notably, tea plants treated with BCY exhibited greater height, biomass, and improved nutrient uptake (nitrogen, potassium, sodium, and Mg). Correspondingly, tea quality was significantly improved, with elevated levels of polyphenols, amino acids, caffeine, and aromatic compounds. Mg-modified biochar derived from tea pruning residues effectively ameliorates acidic soils, alleviates Mg deficiency, and stimulates microbial activity in tea plantations. These soil improvements result in better plant growth, nutrient uptake, and ultimately lead to superior tea quality and yield. These findings support its potential as a sustainable soil amendment in tea plantation management. ● Tea pruning biochar raises soil pH and decreases exchangeable acidity (H + , Al 3+ ) in tea soils. ● Mg-modified biochar (BCY) boosts soil exchangeable Mg 2+ and nutrient availability. ● BCY application promotes the biosynthesis of key aromatic compounds in tea. ● BCY increased soil microbial activity/diversity and improved tea quality and biomass.