Affiliation:
1. School of Ecological Engineering, Guizhou University of Engineering Science, Bijie 551700, China
2. Guizhou Province Key Laboratory of Ecological Protection and Restoration of Typical Plateau Wetlands, Guizhou University of Engineering Science, Bijie 551700, China
Abstract
Nitrogen (N) and phosphorus (P) play crucial roles in tea planting, but information on how the long-term excessive application of chemical N fertilizer affected N and P in subtropical tea plantations remains limited. In this study, soil and leaf samples were collected along a chronosequence of tea plantations (0-, 5-, 10-, 18- and 23-year-old plantations) with excessive N input but no P application to investigate the effects of planting age on N and P availability. Diverse soil N forms and P fractions, and the concentrations of leaf N and P were measured. The results showed that (1) NO3−-N and dissolved organic nitrogen (DON) concentrations in both topsoil and subsoil, and the N concentration of mature leaf showed significant upward trends with tea plantation age; (2) the concentrations of available phosphorus (AP), NaHCO3-Pi in labile P pool, NaOH-Pi and D.HCl-Pi in moderately labile P pool in both layers of soil and that the P concentration of mature leaf also increased with age; (3) the N concentration of mature leaves had closely significant logarithmic relations with NO3−-N concentration, while the TP (total P) concentration of mature leaves had significant positive correlations with AP; and (4) the ratio of N/P in tea leaves indicated a slightly P limitation in tea plantations. We concluded that the NO3−-N concentration, instead of TN (total N) of NH4+-N, would be a good indicator to reflect N availability for tea trees, and the increasing of NO3−-N concentration in soil has a diminishing promoting effect on the TN concentration of mature leaves. The long-term application of chemical N fertilizer had not lead to serious P limitation in subtropical tea plantations. Generally, our study could contribute to improving our understanding of N and P availability and optimizing fertilization management in subtropical tea plantations.
Funder
Guizhou Provincial Science and Technology Project
Regional First-class Discipline of Ecology in Guizhou Province
Bijie Talent Team of Biological Protection and Ecological Restoration in Liuchong River Basin
Bijie Science and Technology Project
Subject
Plant Science,Agronomy and Crop Science,Food Science