Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic cha...Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.展开更多
We conducted a three-month field experiment focusing on the physical and chemical characteristics of fog in a tropical rainforest in Xishuangbanna,Southwest China,in the winter of 2019.In general,the fog would form at...We conducted a three-month field experiment focusing on the physical and chemical characteristics of fog in a tropical rainforest in Xishuangbanna,Southwest China,in the winter of 2019.In general,the fog would form at midnight and persist because of the increased long-wave radiative cooling combined with the high relative humidity,gentle breeze,and a relatively low aerosol number concentration in the forest;the fog would dissipate before noon due to the increasing turbulence near the surface.This diurnal cycle is typical for radiation fog.The microphysical fog properties included a relatively low number concentration of the fog droplet,large droplet size,high liquid water content,narrow droplet number-size distribution,and high supersaturation.The chemical properties showed that the fog water was slightly alkaline with low electrical conductivity,whereas the highest proportions of anions and cations therein were Cl^(−)and Ca^(2+),respectively;the chemical components were enriched in small fog droplets.In addition,we indirectly calculated the fog supersaturation according to theκ-Köhler theory.We found that condensation broadens the droplet number-size distribution at relatively low supersaturation,which is positively correlated with the fog-droplet number concentration and negatively correlated with the droplet mean-volume diameter;this affects the key microphysical processes of fog.展开更多
基金supported by the Project of Qinghai Science&Technology Department(Grant No.2021-ZJ-956Q).
文摘Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.41775134,41822504,41675136,and 41671209)the Innovative Project of Postgraduates in Jiangsu Province(Grant Nos.KYCX20_0920).
文摘We conducted a three-month field experiment focusing on the physical and chemical characteristics of fog in a tropical rainforest in Xishuangbanna,Southwest China,in the winter of 2019.In general,the fog would form at midnight and persist because of the increased long-wave radiative cooling combined with the high relative humidity,gentle breeze,and a relatively low aerosol number concentration in the forest;the fog would dissipate before noon due to the increasing turbulence near the surface.This diurnal cycle is typical for radiation fog.The microphysical fog properties included a relatively low number concentration of the fog droplet,large droplet size,high liquid water content,narrow droplet number-size distribution,and high supersaturation.The chemical properties showed that the fog water was slightly alkaline with low electrical conductivity,whereas the highest proportions of anions and cations therein were Cl^(−)and Ca^(2+),respectively;the chemical components were enriched in small fog droplets.In addition,we indirectly calculated the fog supersaturation according to theκ-Köhler theory.We found that condensation broadens the droplet number-size distribution at relatively low supersaturation,which is positively correlated with the fog-droplet number concentration and negatively correlated with the droplet mean-volume diameter;this affects the key microphysical processes of fog.
