Bleaching of leaf litter accelerates the decomposition of recalcitrant components and mobilization of nitrogen in a subtropical forest

Abstract

Selective removal of lignin and other recalcitrant compounds, collectively registered as acid-unhyrolyzable residue (AUR), results in bleaching of leaf litter, but the importance of bleaching in decomposition processes on forest soil has not been fully evaluated. The aims of this study were to elucidate the occurrence of bleached area in decomposing leaf litter and to compare chemical composition between bleached and nonbleached portions in a subtropical forest in Japan. Field incubation of leaf litter was performed over an 18-month period with the litterbag method. The decomposition processes during the first 9 month were characterized by the relatively rapid mass loss and increase of bleached area, whereas the mass loss was slowed down and the bleached area decreased thereafter. Mass loss of leaf tissues was faster and AUR content was lower in bleached than in nonbleached portions, indicating the acceleration of mass loss in bleached leaf tissues by the selective decomposition of recalcitrant compounds. The decrease in carbonyl-C in the bleached portions was associated with the increase of extractable nitrogen. The results suggest that the bleaching plays a dominant role in the transformation and turnover of organic compounds and nitrogen in decomposing leaf litter.

Teak (Tectona grandis Linn. f) and Edaphic Factors Affecting the Regeneration of Woody Species and Their Functional Traits in Economic Forest Plantation, Northern Thailand

“…Tese sites tended to have high levels of OM and soil N due to leaf litter accumulation and decomposition. Leaf litter decomposition and the consequent accumulations of OM and N are crucial components of ecosystem functioning in forest soils [54,55]. Organic matter maintains soil structure, especially in fne-textured soil [56].…”