7Be penetrative depth in undisturbed surface soil is within 4mm.^7Be activity shows exponential decrease with soil depth,which is expressed as a diffusion process.7Be penetrative depth in undisturbed surface soil is a...7Be penetrative depth in undisturbed surface soil is within 4mm.^7Be activity shows exponential decrease with soil depth,which is expressed as a diffusion process.7Be penetrative depth in undisturbed surface soil is apparently deeper in the fall (0.22-0.37g cm^-1) than in the spring (0.11-0.28g cm^-2) at the same site;Whereas,^7Be apparent activity at the top of surface soil is higher in the spring (0.3-2.2Bq g^-1)than in the fall (0.2-0.5Bqg^-1) at the same site,The 7Be inventory(189-544Bq m^-2)changes with both locations and seasons.Although the ^7Be flux to the earth's surface increases with amount of precipitation,its maximum inventory in the soil profiles decreases to 30%-40% after the rainy period.Calculated by the diffusion equation,the erosion and accumulation rates of soil particles are agreeable with the observation in situ,Which shows that the rates in fall are 1.5 times those in spring.The eroded soil particles almost all have been removed on the tablelands rathel than transported into the drainage system.This indicates that the soil erosion process in the karst region is only partial transportation within a short distance.展开更多
文摘7Be penetrative depth in undisturbed surface soil is within 4mm.^7Be activity shows exponential decrease with soil depth,which is expressed as a diffusion process.7Be penetrative depth in undisturbed surface soil is apparently deeper in the fall (0.22-0.37g cm^-1) than in the spring (0.11-0.28g cm^-2) at the same site;Whereas,^7Be apparent activity at the top of surface soil is higher in the spring (0.3-2.2Bq g^-1)than in the fall (0.2-0.5Bqg^-1) at the same site,The 7Be inventory(189-544Bq m^-2)changes with both locations and seasons.Although the ^7Be flux to the earth's surface increases with amount of precipitation,its maximum inventory in the soil profiles decreases to 30%-40% after the rainy period.Calculated by the diffusion equation,the erosion and accumulation rates of soil particles are agreeable with the observation in situ,Which shows that the rates in fall are 1.5 times those in spring.The eroded soil particles almost all have been removed on the tablelands rathel than transported into the drainage system.This indicates that the soil erosion process in the karst region is only partial transportation within a short distance.
