Methodologies to simulate soil litter decomposition in silvopastoral systems using soil and ruminal incubation

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡库区森林凋落叶化学计量学性状变化及与分解速率的关系 DOI: 10.5846/stxb201304090653 作者: 作者单位: 中国林业科学研究院亚热带林业研究所,中国林业科学研究院森林生态环境与保护研究所,中国林业科学研究院森林生态环境与保护研究所,中国林业科学研究院森林生态环境与保护研究所,中国林业科学研究院亚热带林业研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项(201104008); 长江三峡库区(秭归)森林生态定位站资助 Dynamic of leaf litter stoichiometric traits dynamic and its relations with decomposition rates under three forest types in Three Gorges Reservoir Area Author: Affiliation: Research Institute of Subtropical Forestry, Chinese Academy of Forestry,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry,Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:凋落物分解是森林生态系统生物元素循环和能量流动的重要环节,其过程是植物与土壤获得养分的主要途径。为了量化凋落叶化学计量学性状变化过程对分解的影响及对凋落物-土壤生物化学连续体的深层理解,用凋落物分解袋法研究了不同林型各自凋落叶化学计量学性状变化及与分解速率关系,结果表明:林下各自凋落叶分解速率是马尾松林 <栓皮栎林 <马尾松-栓皮栎混交林,马尾松林、栓皮栎林、马尾松-栓皮栎混交林凋落叶分解50%和95%的时间分别是2.11 a和9.15 a,1.93 a和8.45 a,1.76 a和7.77 a;凋落叶分解过程中,化学计量学性状变化明显,分解450 d后马尾松-栓皮栎混交林碳释放最快,栓皮栎林最慢;3种凋落叶起始N含量是栓皮栎林最高,马尾松林最低,分解450 d后马尾松林、栓皮栎林和马尾松-栓皮栎混交林N含量分别增加了66.67%、44.91%和44.52%,而P含量分别释放了30.80%、38.89%和42.29%。凋落物不同化学计量学性状与分解速率关系不同,3种林型凋落叶分解速率均与N含量呈正相关 (P<0.01),与C含量 (P<0.01)、C/N比 (P<0.01)呈负相关,与N/P比呈负二次函数关系 (P<0.01),而P含量与3种林型关系不同,与栓皮栎林 (P<0.01)和马尾松林(P < 0.05)呈负线性关系,与马尾松-栓皮栎混交林呈负二次函数关系 (P < 0.05)。研究表明,不同林型凋落叶分解中的养分动态趋向利于分解变化,N、P养分动态是生态系统碳平衡和凋落物分解速率的主要因素,混交林中混合凋落物的养分迁移是分解相对较快的原因。 Abstract:Litter decomposition is an important link between bioelement cycles and energy flow in the forest ecosystems, and the main source of nutrients for plants and soil. The relationships were studied between leaf litter stoichiometric traits dynamic and decomposition rate under different forest types using litter bag method in this paper to quantify the effects of stoichiometric traits dynamic on leaf litter decomposition and to get a better understanding to the biochemistry of litter-soil continuum. The results were showed as follows: the sequence of litter decomposition rate for the three forest types was Pinus massoniana stand (PM)< Quercus variabilis stand (QV)< P. massoniana-Q.variabilis mixed stand (PQ) and the litter decomposition rate was more and more significant with time. The remaining dry mass of litter in PM, QV and PQ were 67.59%, 64.75% and 62.13%, respectively after 450 d decomposition. The predicated period of litter decomposition 50% and 95% for PM, QV and PQ was 2.11 a and 9.15 a, 1.93 a and 8.45 a, as well as 1.76 a and 7.77 a, respectively. In these forest types, the concentration of C and P in decomposing litter decreased while N concentration increased with not significant. Leaf litter element dynamic was significantly different. The sequence of the initial C concentration was PQ< QV P<0.01), negatively with C concentration (P<0.01), C/N ratio (P<0.01), and negative quadratic function with N/P ratio (P<0.01). P concentration was different in three stands, and negatively linearly related to the decomposition rate for QV (P<0.01) and PM (P < 0.05), and negative quadratic related for PQ (P < 0.05). The decomposition rate and leaf litter stoichiometry was different among the three stands. The dynamic of C, C/N ratio and N/P ratio in the three stands were similar showing a significant positive correlation with N concentration. The possible reason for this may be that the plants in high latitudes are more susceptible to N restrictions, while those in low latitudes are more susceptible to P restrictions. Whether the plant is limited by N or P, the stoichiometry for different plants is influenced by different environmental factors. This study indicated that the nutrient dynamic during the decomposition of litter leaf under different forest types tend to help itself decompose. The concentration dynamic for N and P was the major factors in regulating carbon balance of ecosystem and litter decomposition, nutrient transfer in mixed litter is the reason for decomposition acceleration. 参考文献 相似文献 引证文献

Decomposition of leaf litter from tropical forage grasses and legumes

Litter decomposition by four functional tree types for use in silvopastoral systems

Wide spread use of pesticides by farmers in agro-ecosystems to control pests may cause the disruption of nutrient cycling by adversely affecting the organisms especially microorganisms, namely bacteria and fungi, involved in decomposition processes thus altering normal nutrient cycling pattern in these ecosystems. This study, therefore, identified and determined the dynamics of bacterial and fungal species involved in cacao leaf litter decomposition and the effect of the pesticide, Ridomil Gold 66WP on the species. This was with a view to understanding the effects of pesticides used to control pests and diseases on litter decomposition rate in cacao plantations. Cacao leaf litter decomposition was studied using litterbag method. Freshly fallen leaf litter was thoroughly mixed and divided into two groups, treated and untreated. The treated was sprayed with Ridomil Gold 66WP at the rate of the recommended field rate of 3.3 g/L and air dried. 20 g of treated and untreated litter were weighed, put in separate 15 cm × 15 cm of 1.0 mm mesh size litter bags and randomly placed on the floor of cacao plantations in Ile-Ife, Nigeria. Three litter bags of each group were randomly retrieved from the plantation on monthly intervals for each month and the content of each litterbag was weighed to determine the rate of decomposition of the litter. The litter contents of each group litter were bulked, ground and microbiological analyses carried out to isolate, characterise and identify the species of bacteria and fungi involved in cacao leaf litter decomposition. The rate of decomposition of pesticide treated cacao leaf litter (0.473) was lower than that of untreated litter (0.582). A total of 31 microbial species consisting of 13 bacterial species and 18 fungal species were isolated from decomposing cacao leaf litter during the sampling period. More fungal species (16) than bacterial species (9) were involved in untreated cacao leaf litter decomposition. Species of the genera Klebsiella, Pseudomonas, Aspergillus, Penicillium and Rhizopus were the most common microorganisms involved in decomposition of cacao leaf litter. Ridomil Gold 66WP did not have significant effect on the total heterotrophic bacterial and fungal counts throughout the sampling period though their counts in treated litter were lower than in untreated litter. There were also no significant monthly variations in both total bacterial and fungal counts. It was concluded that the pesticide, Ridomil Gold 66WP, though had adverse effect on the rate of decomposition of cacao leaf litter, it did not have any adverse effect on the species of bacteria and fungi involved in decomposition of cacao leaf litter.

Towards a functional assessment of stream integrity: A first large-scale application using leaf litter decomposition

Grazing has been considered to be an important factor determining the composition of soil animals and decomposition of leaf litter in grassland ecosystem. Sampling plots were selected in ungrazed grassland, grazed grassland and sandy land. Litter bags were used to compare the changes of physicochemical properties of Stipa grandis litter and the composition of soil fauna in the process of the litter decomposition in Baiyinxile, Inner Mongolia, since 2010 to 2012. A total number of 67056 soil animals were captured, belonging to five phyla and eight classes, including 23 families of mites and 19 families of insects. After 780 days' decomposition, the loss of the organic matter of S. grandis litter was from 92.5% to 40.0% in the ungrazed grassland, and to 41.3% in the grazed grassland, with no significant difference observed. However, there was a significant difference (P<0.05) between the ratio of litter residues of the ungrazed grassland (50.0%) and that of the grazed grassland (23.0%). The abundance of soil animals in the residual litters was significantly decreased in the grazed grassland compared to the ungrazed grassland. When the litter was moved into the sandy land, the decomposition rate of organic matter in the residual litter was not significant changed but the ratio of litter residue declined significantly, and the composition of mite community in the resi-dual litter changed significantly. Our results illustrated that grazing activity could affect the composition and abundance of soil fauna in temperate grassland, but slightly influenced the decomposition of organic matter. Therefore, soil animals had relatively weak direct effects on the decomposition of litter in this semi-arid region.

采用凋落物分解袋法,研究了在土壤、水分相当的条件下模拟增温对红松(<em>Pinus koraiensis</em>)、蒙古栎(<em>Quercus mongolica</em>)及其混合凋落物分解的影响,以及在不同温度水平下,不同凋落物质量(两种单一凋落物和混合凋落物)的分解特性。利用碱式吸收法测量了凋落物分解累积释放CO₂动态。将N浓度和C/N率作为凋落物质量参数,用呼吸产生CO₂的积累值和凋落物质量损失率确定凋落物分解率。结果表明温度升高对单一凋落物和混合凋落物分解均有促进作用,在不同温度水平上,不同质量凋落物的分解特性有所差别,25 ℃和29 ℃条件下混合凋落物分解速率>蒙古栎单一凋落物>红松单一凋落物分解速率。然而,在31 ℃条件下混合凋落物与蒙古栎单一凋落物分解速率相差不大,二者均大于红松单一凋落物分解速率。;Litter decomposition is a fundamental process to ecosystem functioning being responsible of carbon and nutrient cycling. The decomposition of dead leaves depends on both biotic and abiotic factors. The combination of climate (e.g. mean annual temperature (MAT), mean annual precipitation (MAP), actual evapotranspiration, etc) and litter quality (N content, C/N ratio and lignin content) appeared to be the primary controllers of little decomposition. This is particularly true for temperature, which is inextricably linked to other environment parameters as a mutually confounding factor in terrestrial systems. Global average surface air temperature is predicted to increase 1.1-6.4 ℃ over this century. Climate warming is expected to cause species movements and extinctions, change the composition of communities and alter ecosystem functioning. As decomposition depends strongly on temperature, it is expected to be particularly sensitive to climate warming. However, it is still unclear how climate changes influence little decomposition. As global climate changes, it will become warmer and somewhat drier in forest ecosystems, in northeastern China. Changes in global warming and drying could affect forest distribution. The areas of tropical forests and subfrigid forests might increase and that of temperate forests and boreal coniferous forests might decrease, which might affect little quality by altering the structure and species of the original forest communities. The primary temperate forest in northeastern China is dominated by Korean pine (<em>Pinus koraiensis</em> Sieb.et Zucc.) mixed with deciduous species. Many studies showed that <em>Quercus mongolica</em> will become a main associated tree species in broadleaved <em>Pinus koraiensis </em>forest, because it is more conducive to survival under the environment change in future. Therefore, the process of litter decomposition will be affected by climate warming and composition of little species change. Given that decomposition of dead plant tissues in forest ecosystems regulates the transfer of carbon and nutrients to soil, and represents an important source of CO₂ to the atmosphere. It is necessary to carry out research about litter decomposition of the two species under climate change in future. This study used litter bag methods, the whole process use an alkali absorption in a closed chamber method to measured cumulative CO₂ production. We recognized N concentration and C/N ratio as the litter quality parameters, and calculated decomposition rates as cumulative CO₂ production and initial mass remaining. Microcosm experiments under controlled laboratory conditions have proven useful for investigating the various factors that influence litter decomposition. Thus, this study was carried out through a microcosm experiment, in order to:(i) determine the effect of imitate increase temperature on <em>Pinus koraiensis</em>,<em>Quercus mongolica</em> pure and their mix litter decomposition rate and (ii)the effect of litter with different physicochemical properties on litter decomposition rate at the same temperature level under constant moisture condition, during a time period of 151 days incubation in laboratory. Our results suggest that increased temperature accelerated leaf little decomposition rates within both mixed-species litterbags and single-species litterbags. However, its response may vary depending on the level of increased temperature. When the temperature in closed chamber was at 25 ℃ and 29 ℃, decomposition rates within litterbags decreased in the order of mixed-species > single-<em>Quercus mongolica</em> > single-<em>Pinus koraiensis</em>. When the temperature in closed chamber increased to 31 ℃, decomposition rates was faster within mixed-species litterbags and single-<em>Quercus mongolica</em> litterbags than single-<em>Pinus koraiensis</em>, but the variation between mixed-species litterbags and single-<em>Quercus mongolica</em> litterbags decomposition rates was not statistically significant. This study has great significance on understanding of forest ecosystem carbon and nutrient cycle.

AimsLitter decomposition is a critical pathway linking the above- and belowground processes. However, factors underlying the local spatial variations in forest litter decomposition are still not fully addressed. We investigated leaf litter decomposition across contrasting forest stands in central China, with objective to determine the spatial variations and controlling factors in forest floor leaf litter decomposition in relation to changes in forest stands in a temperate forest ecosystem.

Aims Grazing intensity and grazing exclusion affect ecosystem carbon cycling by changing the plant community and soil micro-environment in grassland ecosystems. The aims of this study were: 1) to determine the effects of grazing intensity and grazing exclusion on litter decomposition in the temperate grasslands of Nei Mongol; 2) to compare the difference between above-ground and below-ground litter decomposition; 3) to identify the effects of precipitation on litter production and decomposition. Methods We measured litter production, quality, decomposition rates and soil nutrient contents during the growing season in 2011 and 2012 in four plots, i.e. light grazing, heavy grazing, light grazing exclusion and heavy grazing exclusion. Quadrate surveys and litter bags were used to measure litter production and decomposition rates. All data were analyzed with ANOVA and Pearson’s correlation procedures in SPSS. Important findings Litter production and decomposition rates differed greatly among four plots. During the two years of our study, above-ground litter production and decomposition in heavy-grazing plots were faster than those in light-grazing plots. In the dry year, below-ground litter production and decomposition in light-grazing plots were faster than those in heavy-grazing plots, which is opposite to the findings in the wet year. Short-term grazing exclusion could promote litter production, and the exclusion of light-grazing could increase litter decomposition and nutrient cycling. In contrast, heavy-grazing exclusion decreased litter decomposition. Thus, grazing exclusion is beneficial to the restoration of the light-grazing grasslands, and more human management measures 杨丽丽等: 内蒙古温带草原不同放牧强度和围栏封育对凋落物分解的影响 749 doi: 10.17521/cjpe.2016.0051 are needed during the restoration of heavy-grazing grasslands. Precipitation increased litter production and decomposition, and below-ground litter was more vulnerable to the inter-annual change of precipitation than above-ground litter. Compared to the light-grazing grasslands, heavy-grazing grasslands had higher sensitivity to precipitation. The above-ground litter decomposition was strongly positively correlated with the litter N content (R = 0.489, p < 0.01) and strongly negatively correlated with the soil total N content (R = 0.450, p < 0.01), but it was not significantly correlated with C:N and lignin:N. Below-ground litter decomposition was negatively correlated with the litter C (R = 0.263, p < 0.01), C:N (R = 0.349, p < 0.01) and cellulose content (R = 0.460, p < 0.01). Our results will provide a theoretical basis for ecosystem restoration and the research of carbon cycling.

Introduction The availability of mineral nutrients in the karst ecosystem is specifically influenced by vegetation, which depends on how much nutrition is contributed by the litter of the stand through the decomposition process. The litter decomposition rate can be observed through physical changes and a decrease in litter weight. The community in Pracimantoro utilizes and maintains land by building community forests to optimize land in the karst area. This study aims to determine the litter decomposition rate in several community forest planting patterns in Pracimantoro. Methods Data were collected using the litter bag method by making sample plots measuring 0.04 ha and selected by purposive sampling, and placed diagonally. The rate of decomposition is described by the constant value (k). Results The karst community forest in Pracimantoro was dominated by Mahogany (Swietenia sp.), Acacia (Acacia auriculiformis), and Teak (Tectona grandis) stands. The rate of decomposition in the Pracimantoro karst community forest was 0.0268. Discussion Leaf litter decomposition over two months resulted in a decrease in litter weight of 33.05%. The duration of nutrient return in karst community forests can be estimated using the half-life approach. Conclusion The rate of litter decomposition is influenced by environmental conditions and litter quality. Environmental conditions that are suitable over a long period have a significant impact on the rate of litter decomposition.

Background and Aims The influence of soil fauna on litter decomposition is rarely explored in tropical rain forest. This study examined the effect of soil fauna on the decomposition of mixed substrate by litter bag technical at two tropical seasonal rain forest plots in Xishuangbanna,SW China in year of 2000. The following questions were considered in the present study: 1) What roles do soil fauna play in regulating litter mass loss and decomposition rate? 2) How do soil fauna influence litter nutrient release? Methods In order to examine the role of soil macro-mesofauna in mass loss and nutrient release of litter,litter bags with both fine mesh size (0.15 mm) that excludes the soil macro-mesofauna population from litter and coarse mesh size (2 mm) that allows soil fauna access to litter were used in this experiment. Mass loss and C,N,P,S,K,Ca,and Mg concentrations of leaf litter were determined from the litter in two different mesh size litterbags at monthly intervals. The soil fauna were extracted by hand and by heating the samples. Key Results Higher relative density and taxonomic diversity of total soil fauna were found in the bags with 2 mm mesh size (22.3-21.77 individuals and 2.67-2.83 orders per g of dry litter) compared to the bags with 0.15 mm mesh size (2.88-2.77 individuals and 0.27-0.28 orders per g of dry litter). Collembola and Acari were the most abundant group,and Hymenoptera(ant),Coleoptera,Hemiptera,Diptera,Diplopoda,Isopoda,Araneae,Pseudoscorpiones were common groups of soil fauna in litter bags with 2 mm mesh size. There were very few individuals of Collembola and Acari in the 0.15 mm litter bags. Our results suggested that soil macro-mesofauna contributed more to the decomposition of leaf litter in 2 mm litter bags than that in 0.15 mm litter bags. The higher mass loss rate (around 71%),decomposition rate (k=1.88-2.44),and nutrient release in litter bags with 2 mm mesh size than in litter bags with 0.15 mm mesh size (34%-35%,k= 0.48- 0.58) indicated a significant influence of soil macro-mesofauna on mass loss and nutrient release in tropical seasonal rain forest. The release rates of N,S and Ca that could be attributable to the soil macro-mesofauna were higher than other elements whereas K release rate that could be attributable to the soil macro-mesofauna was the lowest. Soil macro-mesofauna caused greater decreases in C/N and C/P ratios in litter bags with 2 mm mesh size than litter bags with 0.15 mm mesh size. There were negative relationships of the percentage of litter mass remaining with order richness and individuals abundance of soil fauna. However,a positive relationship between Shannon-Wiener index of soil fauna and the decomposition rate was found. Conclusions This study suggests that the presence of soil fauna accelerated plant litter decomposition in the tropical seasonal rain forest. The litter mass loss attributable to the soil macro-mesofauna was about 46%. The effects of soil macro-mesofauna on the nutrient release rates were different among elements. The diversity of soil fauna may have important ecosystem consequences,particularly in tropical rain forest.

Elucidating the processes of leaf litter and fine root decomposition has been a major research focus, while how the correlation between leaf litter and fine root decomposition is unclear. We studied the in situ decomposition and N dynamics of leaf litter and fine root of four subtropical tree species (Pinus massoniana, Castanopsis hystrix, Michelia macclurei and Mytilaria laosensis) to determine whether leaf litter and fine root decomposition is correlated across species as well as which factors influence decomposition above versus below ground. Decomposition rate of leaf litter was related to that of fine root across species. The strong correlation between leaf litter and fine root decomposition rates arose largely for several reasons. First, soil moisture had the similar influences on both leaf litter and fine root decomposition rates. Second, traits (i.e., initial Ca concentration) important to both leaf litter and fine root decomposition rates showed significant similarity among species. Third, initial P, N and aromatic C concentrations, and C/N ratio were uniquely important for fine root decomposition rate, while no unique traits for leaf litter decomposition rate. This also could account for the strong correlation between leaf litter and fine root decomposition rates. Our study suggests that among these subtropical trees, species effects on in situ decomposition rates of leaf litter and fine root are very similar. Thus, species differences in decomposition rates may be as large as they would be if faster decomposition of leaf litter was correlated with faster decomposition of fine root. N immobilization rate of leaf litter was unrelated to that of fine root across species. Our results help explain some important mechanisms by which tree species influence litter in situ decomposition.

The influence of litter quality and micro-habitat on litter decomposition and soil properties in a silvopasture system

Tree species effects on litter decomposition in pure stands on afforested post-mining sites

Litter decomposition plays a vital role in nutrient cycling and maintaining ecosystem functionality, particularly in forested landscapes. However, the decomposition dynamics of common tropical timber species remain underexplored in many regions, including Bangladesh. This study investigated the leaf litter decomposition and associated nutrient (nitrogen, phosphorus, potassium) release patterns of five widely planted timber species, Chukrasia tabularis, Dipterocarpus turbinatus, Hopea odorata, Tectona grandis, and Swietenia macrophylla on the Chittagong University campus. Using the litter bag method, decomposition rates were measured across both dry and wet seasons to assess seasonal variability and environmental influences. The results revealed that Chukrasia tabularis exhibited the highest mass loss (33% in the dry season and 60% in the wet season), followed by Hopea odorata (38% and 55%), while Tectona grandis showed the lowest decomposition rates (23% and 25%). Decomposition was most rapid in Hopea odorata during the dry season (0.57 g/month) and Dipterocarpus turbinatus in the wet season (0.89 g/month). In the wet season, decomposition rates were significantly (p &lt; 0.05) correlated with temperature and precipitation across all species. In contrast, during the dry season, only Tectona grandis and Hopea odorata showed significant correlations with temperature, while only Chukrasia tabularis and Hopea odorata were significantly influenced by precipitation. Nutrient release patterns varied by species and nutrient type: nitrogen release was highest in Chukrasia tabularis (26.89 mg/g), phosphorus in Hopea odorata (16.53 mg/g), and potassium in Dipterocarpus turbinatus (53.53 mg/g), whereas Swietenia macrophylla consistently showed the lowest nutrient release rates. These findings highlight species-specific and seasonal variations in litter decomposition and nutrient dynamics, offering insights for forest management, species selection, and ecosystem nutrient budgeting in tropical forest plantations.