Aims We aim to construct a comprehensive global database of litter decomposition rate(k value)estimated by surface floor litterbags,and investigate the direct and indirect effects of impact factors such as geographic ...Aims We aim to construct a comprehensive global database of litter decomposition rate(k value)estimated by surface floor litterbags,and investigate the direct and indirect effects of impact factors such as geographic factors(latitude and altitude),climatic factors(mean annual tempePlrature,MAT;mean annual precipitation,MAP)and litter quality factors(the contents of N,P,K,Ca,Mg and C:N ratio,lignin:N ratio)on litter decomposition.Methods We compiled a large data set of litter decomposition rates(k values)from 110 research sites and conducted simple,multiple regression and path analyses to explore the relationship between the k values and impact factors at the global scale.Important findings The k values tended to decrease with latitude(LAT)and lignin content(LIGN)of litter but increased with temperature,precipitation and nutrient concentrations at the large spatial scale.Single factor such as climate,litter quality and geographic variable could not explain litter decomposition rates well.However,the combination of total nutrient(TN)elements and C:N accounted for 70.2%of the variation in the litter decomposition rates.The combination of LAT,MAT,C:N and TN accounted for 87.54%of the variation in the litter decomposition rates.These results indicate that litter quality is the most important direct regulator of litter decomposition at the global scale.This data synthesis revealed significant relationships between litter decomposition rates and the combination of climatic factor(MAT)and litter quality(C:N,TN).The global-scale empirical relationships developed here are useful for a better understanding and modeling of the effects of litter quality and climatic factors on litter decomposition rates.展开更多
通过外加氮源或将杉木针叶与林下植物叶混合来改变杉木林凋落物中针叶的养分状况,与杉木林针叶凋落物分解进行比较,分析针叶养分状况及其对杉木林凋落物分解速率和养分释放的影响.结果表明:将杉木针叶与林下植物叶混合和外加氮源均对凋...通过外加氮源或将杉木针叶与林下植物叶混合来改变杉木林凋落物中针叶的养分状况,与杉木林针叶凋落物分解进行比较,分析针叶养分状况及其对杉木林凋落物分解速率和养分释放的影响.结果表明:将杉木针叶与林下植物叶混合和外加氮源均对凋落物分解有不同程度的促进作用.经过153 d的分解后,未经处理的杉木针叶干质量损失率为20.49%,与林下植物叶混合的凋落物干质量损失率为43.67%,其促进作用最大;外加4 gNaNO3的促进作用次之,凋落物干质量损失率为42.07%;外加2 g NaNO3的凋落物干质量损失率为29.13%.对分解过程中各试验方案的凋落物干质量保留率进行方差分析,在开始的62 d内,与林下植被叶混合的杉木针叶凋落物分解速率和其他3种处理之间的差异显著,62 d后未经处理的杉木针叶与加2 g NaNO3的凋落物的分解速率没有显著差异,它们与加4 g NaNO3或林下植物叶的凋落物的分解速率差异显著.凋落物分解速率与凋落物初始C:N比值存在显著的线性关系.外加N源和与林下植物叶混合后,凋落物N的含量增加0.6～1.6倍,C:N比值下降0.4～0.6倍,凋落物底物质量提高,分解速率增大.分解过程中,C质量不断下降,损失24.7%～47.4%,杉木针叶中N出现富集作用,外加N源和与林下植物叶混合的凋落物N释放一定数量后保持稳定的状态.可见,外加适量N源和与林下植物叶混合能提高凋落物底物质量,促进凋落物分解和养分的释放,对维持杉木林的土壤肥力有着重要作用.展开更多
基金supported by the Chinese Ecosystem Research Net(CERN)NSFC(30570350,40730102,30725006)+1 种基金by the Office of Science(BER),U.S.Department of Energy,Grant No.DE-FG03-99ER62800through the South Central Regional Center of the National Institute for Global Environmental Change under Cooperative Agreement No.DE-FC03-90ER61010.
文摘Aims We aim to construct a comprehensive global database of litter decomposition rate(k value)estimated by surface floor litterbags,and investigate the direct and indirect effects of impact factors such as geographic factors(latitude and altitude),climatic factors(mean annual tempePlrature,MAT;mean annual precipitation,MAP)and litter quality factors(the contents of N,P,K,Ca,Mg and C:N ratio,lignin:N ratio)on litter decomposition.Methods We compiled a large data set of litter decomposition rates(k values)from 110 research sites and conducted simple,multiple regression and path analyses to explore the relationship between the k values and impact factors at the global scale.Important findings The k values tended to decrease with latitude(LAT)and lignin content(LIGN)of litter but increased with temperature,precipitation and nutrient concentrations at the large spatial scale.Single factor such as climate,litter quality and geographic variable could not explain litter decomposition rates well.However,the combination of total nutrient(TN)elements and C:N accounted for 70.2%of the variation in the litter decomposition rates.The combination of LAT,MAT,C:N and TN accounted for 87.54%of the variation in the litter decomposition rates.These results indicate that litter quality is the most important direct regulator of litter decomposition at the global scale.This data synthesis revealed significant relationships between litter decomposition rates and the combination of climatic factor(MAT)and litter quality(C:N,TN).The global-scale empirical relationships developed here are useful for a better understanding and modeling of the effects of litter quality and climatic factors on litter decomposition rates.
文摘通过外加氮源或将杉木针叶与林下植物叶混合来改变杉木林凋落物中针叶的养分状况,与杉木林针叶凋落物分解进行比较,分析针叶养分状况及其对杉木林凋落物分解速率和养分释放的影响.结果表明:将杉木针叶与林下植物叶混合和外加氮源均对凋落物分解有不同程度的促进作用.经过153 d的分解后,未经处理的杉木针叶干质量损失率为20.49%,与林下植物叶混合的凋落物干质量损失率为43.67%,其促进作用最大;外加4 gNaNO3的促进作用次之,凋落物干质量损失率为42.07%;外加2 g NaNO3的凋落物干质量损失率为29.13%.对分解过程中各试验方案的凋落物干质量保留率进行方差分析,在开始的62 d内,与林下植被叶混合的杉木针叶凋落物分解速率和其他3种处理之间的差异显著,62 d后未经处理的杉木针叶与加2 g NaNO3的凋落物的分解速率没有显著差异,它们与加4 g NaNO3或林下植物叶的凋落物的分解速率差异显著.凋落物分解速率与凋落物初始C:N比值存在显著的线性关系.外加N源和与林下植物叶混合后,凋落物N的含量增加0.6～1.6倍,C:N比值下降0.4～0.6倍,凋落物底物质量提高,分解速率增大.分解过程中,C质量不断下降,损失24.7%～47.4%,杉木针叶中N出现富集作用,外加N源和与林下植物叶混合的凋落物N释放一定数量后保持稳定的状态.可见,外加适量N源和与林下植物叶混合能提高凋落物底物质量,促进凋落物分解和养分的释放,对维持杉木林的土壤肥力有着重要作用.
