Foliar N Application on Tea Plant at Its Dormancy Stage Increases the N Concentration of Mature Leaves and Improves the Quality and Yield of Spring Tea.

Mei-Ya Liu,Yuanzhi Shi,Dandan Tang,Jianyun Ruan,Lifeng Ma,Qunfeng Zhang

doi:10.3389/fpls.2021.753086

Abstract

Over 30% of the Chinese tea plantation is supplied with excess fertilizer, especially nitrogen (N) fertilizer. Whether or not foliar N application on tea plants at the dormancy stage could improve the quality of spring tea and be a complementary strategy to reduce soil fertilization level remains unclear. In this study, the effects of foliar N application on tea plants were investigated by testing the types of fertilizers and their application times, and by applying foliar N under a reduced soil fertilization level using field and 15N-labeling pot experiments. Results showed that the foliar N application of amino acid liquid fertilizer two times at the winter dormancy stage was enough to significantly increase the N concentration of the mature leaves and improved the quality of spring tea. The foliar application of 2% urea or liquid amino acid fertilizer two times at the winter dormancy stage and two times at the spring dormancy stage showed the best performance in tea plants among the other foliar N fertilization methods, as it reduced the soil fertilization levels in tea plantations without decreasing the total N concentration of the mature leaves or deteriorating the quality of spring tea. Therefore, foliar N application on tea plants at its dormancy stage increases the N concentration of the mature leaves, improves the quality and yield of spring tea, and could be a complementary strategy to reduce soil fertilization levels.

Highlights

Plant leaf is specialized in capturing carbon dioxide (CO2) and light, its capacity to absorb nutrients has long been recognized and exploited in agriculture (Fernández and Eichert, 2009; Eichert and Fernández, 2012)
17 continuous rows (1.8 m × 50 m for one row) of tea plants were selected from the beginning, the first row of tea plants beneath the road was set as a protection row, followed by three rows of each treatment with zero (T0; control), one (T1), two (T2), three (T3), and four (T4) times application of foliar N, and the last row within the 17 continuous rows was designated as a protection row
There were four treatments of foliar 15N-urea application, two times at the winter dormancy stage (TW), two times in spring before the sprouting of dormant buds (TS), a combination of two times at the winter and spring dormancy stage (TWS), and no 15N-urea application (CK)

Summary

Introduction

Plant leaf is specialized in capturing carbon dioxide (CO2) and light, its capacity to absorb nutrients has long been recognized and exploited in agriculture (Fernández and Eichert, 2009; Eichert and Fernández, 2012). The absorption of foliar N fertilizers by plants depends on several factors, such as the type and concentration of the foliar N fertilizers applied, the N or the nutrient status of both the plant and soil, the developmental stage of the plant, as well as environmental factors. Taking these into account, the appropriate timing and management of foliar N sprays have been well-developed to improve the efficacy of foliar N fertilization (Eichert and Fernández, 2012)

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Conclusion