Effect on the growth and quality of young tea plants due to neutralization of tea soil with slag

Abstract

In tea cultivation, excessive use of nitrogen (N) for fertilization can lead to severe soil acidification and environmental pollution due to leaching of N that, in turn, hinders tea plants’ growth. In this study, we investigated the effects of pH neutralization in acidic tea soils using alkaline slag. We applied a mix of blast furnace slag (10, 20％), molten slag (10, 20％), and steelmaking slag (1, 2％) to the tea soils. First-year tea cuttings were planted, and we sampled new tea shoots twice over four months. The findings showed that the application of slag increased the pH of tea soils, with steelmaking slag, blast furnace slag, and then molten slag being the most effective. The growth and quality components of young tea plants remained stable after the application of blast furnace slag and molten slag, but steelmaking slag showed some inhibitory effects. Moreover, the amount of N leaching increased after using blast furnace slag and steelmaking slag, while it decreased after applying molten slag. This suggests that N utilization efficiency improved in young tea plants with molten slag. In conclusion, the application of slag materials can maintain the optimal soil pH range for tea growth, leading to improved growth, quality, and N utilization efficiency of young tea plants. Slag appears to be a useful material for pH neutralization in heavily acidic tea soils.