Litter decomposition and the degradation of recalcitrant components in Pinus massoniana plantations with various canopy densities

Jie Zhang,Danju Zhang,Zhang Jian,Daping Wei,Hongyang Zhou,Yanbo Zhao

doi:10.1007/s11676-018-0715-5

Abstract

To understand the decomposition characteristics of Pinus massoniana foliar litter and the degradation of its refractory compounds in plantations under five canopy densities, a litter bag experiment over a decomposition time of 392 days was carried out. The results show that canopy density significantly affected decomposition rates of litter and degradation rate of lignin and cellulose. Litter decomposition rates decreased significantly with decreasing canopy density. Both lignin and cellulose degradation rates were lower with canopy densities of 0.62 and 0.74 as compared with the three other densities. Lignin and cellulose losses were more rapid in the first 118 days. Soil fauna had significant impacts on litter decomposition and the degradation of refractory compounds. Canopy density had significant effects on factors such as soil properties and soil fauna community structure, which could be conducive to the decomposition of litter and the degradation of litter recalcitrant components. Canopy density between 0.6 and 0.7 might be a favorable management practice promoting litter decomposition and beneficial for the sustainable development of P. massoniana plantations.

Highlights

Litter decomposition is one of the most important ecological processes contributing to nutrient cycling in forests, and an important link between the material cycle and energy flows (Berg and McClaugherty 2008; Herman et al 2008).Litter decomposition includes decomposed components as well as material resistant to decomposition
The results show that canopy density significantly affected decomposition rates of litter and degradation rate of lignin and cellulose
The purpose of this study was to assess the characteristics of litter degradation and its two recalcitrant components, lignin and cellulose, over a 392-day period in plantations with different canopy densities we aimed to identify a favorable canopy density that would facilitate the decomposition of litter and hypothesized that litter degradation changes significantly under various canopy densities

Summary

Introduction

Litter decomposition is one of the most important ecological processes contributing to nutrient cycling in forests, and an important link between the material cycle and energy flows (Berg and McClaugherty 2008; Herman et al 2008).Litter decomposition includes decomposed components as well as material resistant to decomposition. The early stages of decomposition of foliar litter is predominantly a fast, physical leaching process (Wu et al 2010) during which water-soluble components and a small amount of labile organic components are degraded (Couteaux et al 1995). Organic components that are difficult to break down (lignin, cellulose) begin to decompose (Berg and McClaugherty 2008). Compared with broad-leaved tree species, the needles of conifers contain more recalcitrant secondary metabolites such as cellulose, hemicelluloses, lignin, and tannins (Guo et al 2009)

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