In order to expound the role of litter in controlling soil and water loss,the soil and water conservation functions of litter in Chinese pine stand have been studied,using the method of location monitor combined with ...In order to expound the role of litter in controlling soil and water loss,the soil and water conservation functions of litter in Chinese pine stand have been studied,using the method of location monitor combined with simulation experiment.The results of the studies showed that the average interception rate of the litter is 12.4%,it’s retarding effect on runoff is related to litter thickness,slope and runoff depth.The mathematical equation between them is ΔT =13.490· l 0.245 · α -0.200 · q -0.186 ,the annual soil evaporation restrained by litter of 2 cm in thickness is 138 6mm,and the litter of 1 5 cm in thickness can decrease the splash erosion by 97 5% and increase soil antiscourability by 96 7%.Compared with the bare slope,the physical and chemical properties of soil covered with litter are improved obviously.All these provide the scientific basis for the rational management of forest and the estabishment of the optimal structure of stand.展开更多
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
The hydrological character parameters of the litter amount, the maximum water capacity and water absorption speed of the litter on the forest land under four type of \%Abies fabri\% forest (young, half_mature,mature a...The hydrological character parameters of the litter amount, the maximum water capacity and water absorption speed of the litter on the forest land under four type of \%Abies fabri\% forest (young, half_mature,mature and overmature stand)on the Gongga Mountain were studied in this paper. The result showed that the litter amount under the overmature stand was the maximum(67 8?t·hm -2 ), the second was the mature stand(53 4 t·hm -2 ), the third was the half mature stand(40 4 t·hm -2 ), the fourth was the young stand(32 6?t·hm -2 ). The maximum water capacity of the undecomposed litter under the mature stand was 428 8% of the litter’s dry weight, that of the litter under the overmature stand was 411 6%, that of the litter under the half_mature stand was 378 8%, that of the litter under the young stand was 296 7%. The maximum water capacity of the half_decomposed litter under the mature stand was 234 5% of the litter’s dry weight, that of the litter under the overmature stand was 175 6%, that of the litter under the half mature stand was 160 3%, that of the litter under the young stand was 132 5%. The equation between the water absorption speed of the litter and the soaked time is S=kt n. The result also shows that the litter’s variation with the time has no relation to forest age, while its decomposition degree is positively related to stand age.展开更多
文摘In order to expound the role of litter in controlling soil and water loss,the soil and water conservation functions of litter in Chinese pine stand have been studied,using the method of location monitor combined with simulation experiment.The results of the studies showed that the average interception rate of the litter is 12.4%,it’s retarding effect on runoff is related to litter thickness,slope and runoff depth.The mathematical equation between them is ΔT =13.490· l 0.245 · α -0.200 · q -0.186 ,the annual soil evaporation restrained by litter of 2 cm in thickness is 138 6mm,and the litter of 1 5 cm in thickness can decrease the splash erosion by 97 5% and increase soil antiscourability by 96 7%.Compared with the bare slope,the physical and chemical properties of soil covered with litter are improved obviously.All these provide the scientific basis for the rational management of forest and the estabishment of the optimal structure of stand.
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The hydrological character parameters of the litter amount, the maximum water capacity and water absorption speed of the litter on the forest land under four type of \%Abies fabri\% forest (young, half_mature,mature and overmature stand)on the Gongga Mountain were studied in this paper. The result showed that the litter amount under the overmature stand was the maximum(67 8?t·hm -2 ), the second was the mature stand(53 4 t·hm -2 ), the third was the half mature stand(40 4 t·hm -2 ), the fourth was the young stand(32 6?t·hm -2 ). The maximum water capacity of the undecomposed litter under the mature stand was 428 8% of the litter’s dry weight, that of the litter under the overmature stand was 411 6%, that of the litter under the half_mature stand was 378 8%, that of the litter under the young stand was 296 7%. The maximum water capacity of the half_decomposed litter under the mature stand was 234 5% of the litter’s dry weight, that of the litter under the overmature stand was 175 6%, that of the litter under the half mature stand was 160 3%, that of the litter under the young stand was 132 5%. The equation between the water absorption speed of the litter and the soaked time is S=kt n. The result also shows that the litter’s variation with the time has no relation to forest age, while its decomposition degree is positively related to stand age.
