Contrasting decomposition rates and nutrient release patterns in mixed vs singular species litter in agroforestry systems
The rate of litter decomposition can be affected by a suite of factors, including the diversity of litter type in the environment. The effect of mixing different litter types on decomposition rates is increasingly being studied but is still poorly understood. We investigated the effect of mixing either litter material with high nitrogen (N) and phosphorus (P) concentrations or those with low N and P concentrations on litter decomposition and nutrient release in the context of agroforestry systems.
Materials and methods
Poplar leaf litter, wheat straw, peanut leaf, peanut straw, and mixtures of poplar leaf litter-wheat straw, poplar leaf litter-peanut leaf, and poplar leaf litter-peanut straw litter samples were placed in litter bags, and their rates of decomposition and changes in nutrient concentrations were studied for 12 months in poplar-based agroforestry systems at two sites with contrasting soil textures (clay loam vs silt loam).
Results and discussion
Mixing of different litter types increased the decomposition rate of litter, more so for the site with a clay loam soil texture, representing site differences, and in mixtures that included litter with high N and P concentrations (i.e., peanut leaf). The decomposition rate was highest in the peanut leaf that had the highest N and P concentrations among the tested litter materials. Initial N and P immobilization may have occurred in litter of high carbon (C) to N or C to P ratios, with net mineralization occurring in the later stage of the decomposition process. For litter materials with a low C to N or P ratios, net mineralization and nutrient release may occur quickly over the course of the litter decomposition.
Non-additive effects were clearly demonstrated for decomposition rates and nutrient release when different types of litter were mixed, and such effects were moderated by site differences. The implications from this study are that it may be possible to manage plant species composition to affect litter decomposition and nutrient biogeochemistry; mixed species agroforestry systems can be used to enhance nutrient cycling, soil fertility, and site productivity in land-use systems.
KeywordsAgroforestry Litter decomposition Mixing Non-additive effect Nutrient release
This work was supported by the National Basic Research Program of China (973 Program, 2012CB416904), the National Forestry Public Welfare Research Project of China (No. 201004004), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). We would like to acknowledge Dr. Luozhong Tang, Professor Xizeng Xu, and Mr. Xiaoliang Lu for their able assistance in establishing the experimental plantation and in data collection. We thank two anonymous reviewers for their comments that improved the quality of an earlier version of the manuscript.
- Li HT, Yu GR, Li JY, Chen YR, Liang T (2007) Decomposition dynamics and nutrient release of litters for four artificial forests in the red soil and hilly region of subtropical China. Acta Ecol Sin 27:898–908Google Scholar
- Lin KM, Zhang ZQ, Cao GQ, He ZM, Ma XQ (2006) Decomposition characteristics and its nutrient dynamics of leaf litter mixtures of both Chinese fir and Phoeba bournei. Acta Ecol Sin 8:2732–2738Google Scholar
- Song XZ, Jiang H, Yu SQ, Ma YD, Zhou GM, Dou RP, Guo PP (2009) Litter decomposition of dominant plant species in successional stages in mid-subtropical zone. Chinese J Appl Ecol 20:537–542Google Scholar
- Wang L, Zhang H, Zhu Q, Jiang Y, Yan K, Wang F (2010) Characteristics of soil nitrogen mineralization in different aged stands and the successive rotation stands of poplar plantation. J Henan Agr Univ 44:28–33Google Scholar
- Zhang J, Kong Y, Wang Y, Yang C, Hu D (2010) Components separation of soil respiration in two typical shelter forestlands in silting coastal area, Northern Jiangsu Province. Acta Ecol Sin 30:3144–3154Google Scholar