Effects of organic fertilizers on changes of functional traits in vegetative growth period of Leymus chinensis

Abstract

Abstract [Objective] This paper studied the changes, response mechanism, and correlation of functional traits of Leymus chinensis during vegetative growth period under different levels of organic fertilizers, in an attempt to provide reference for the dynamic study of resources, environment, and plant functional characters, as well as restoration of the grassland ecosystems. [Methods] Selecting a grassland that had not been fertilized for more than 20 years as the experimental site, which was enclosed and divided into several small areas. Setting up four levels of organic fertilizer applications, with effective N amounts of 0, 63, 127, and 190 kg/hm2, respectively. Collecting samples before, during, and after the major vegetative growth of L. chinensis, and measuring functional traits. The changing trend, difference, correlation, and influence coefficient of functional characters of L. chinensis were analyzed by conic equation fitting, single factor multivariate analysis of variance, Pearson correlation analysis, and integral (stepwise) regression. [Results] (1) Organic fertilizers increased at beginning and then decreased the leaf length, leaf area, natural leaf width, unfolded leaf width, specific leaf area, stem length, stem mass, and single plant mass of L. chinensis sativus, while leaf dry matter and stem dry matter were decreased. (2) Organic fertilizers changed the correlation among functional characters of L. chinensis, enhancing the correlation between leaf area and specific leaf area, stem length and stem mass, and stem length and single plant mass, while decreasing the correlation between single leaf mass and single plant mass, and leaf width and plant height. (3) Organic fertilizers changed the contribution rate of phenotypic traits, including leaves, stems, and plant heights, to single plant mass. Increasing fertilization levels, the contribution of leaves, stems and plant heights tended to be balanced. The order of phenotypic traits affecting single plant mass of L. chinensis was: Leaves > plant heights > stems. [Conclusion] Short-term application of organic fertilizers had a significant effect on the functional characters of L. chinensis, which was mainly occurred in the later stage of vegetative growth, especially on the single plant mass. Among them, leaf length, unfolding leaf width, leaf area, and plant height had great influence on the single plant mass of L. chinensis, while plant height was the most stable factor driving the change of single plant mass. At the same time, the correlation between functional characters of L. chinensis was affected by the levels of fertilization. Fertilization enhanced the correlation of some functional traits while weakened the correlation among others, and thus there was a balance as a whole.

Keywords

• leymus chinensis
• organic fertilizers
• functional traits
• correlation
• driving factor