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对湖南衡阳盆地紫色土丘陵坡地植物群落进行研究,其生物量具有以下特点:1)衡阳盆地紫色土丘陵坡地植物群落平均总生物量为5 133.6 kg/hm~2,乔木层、灌木层、草本层和枯落物层平均生物量分别为1 936.7、1 624.7、1 400.8和171.4 kg/hm~2,分别占其坡地群落平均总生物量的20.9%、24.1%、50.6%和4.4%.2) 乔木层、灌木层和草本层地上部生物量、根系生物量分别占乔木总生物量、灌木总生物量和草本总生物量的80.2%和19.8%,52.4%和47.6%,43.6%和56.4%.3)乔木层、灌木层、草本层和枯落物层的生物量在不同立地条件其大小顺序依次为:乔木层只在下坡存在;中坡灌木层大于下坡;中坡草本层和枯落物层高,上坡低.4)植物群落枝叶、枯落物、根系生物量占植物群落总生物量的比例其大小顺序是:上坡与中坡根系高、枯落物低,下坡枝叶高,枯落物低.5)草本层的地上部生物量和地下部生物量比值从上坡至下坡逐渐增大.“,”The plant communities in sloping-land with purple soils in Hengyang basin were studied. The results were as follows: (1) The total biomass of the plant communities on the purple soil slope in Hengyang basin was 5 133.6 kg/hm~2, The biomass of the tree layer, the shrub layer, the herbage layer and the deadwood and defoliation layer were 1 936.7, 1 624.7, 1 400.8 and 171.4 kg/hm~2 respectively. They each account for 20.9%, 24.1%, 50.6% and 4.4% of the total biomass of the plant commumities. (2) The percentage of the above-ground biomass and the root biomass in the tree layer, the shrub layer, the herbage layer each was 80.2%, 19.8%; 52.4%, 47.6% and 43.6%, 56.4% respectively. (3) The biomass of the tree layer, the shrub layer and the herbage layer on the sloping-land with purple soils in Hengyang basin was different. The tree layer only exists in the down-slope; the sequence of the biomass of the shrub layer was :the middle-slope >the down-slope; the sequence of the biomass of the herbage layer and the deadwood and defoliation were: the middle-slope > the down-slope >the-upper slope. (4) The percentage of the biomass of the branches and the leaves, the deadwood and defoliation and the root in the total biomass in the upper-slope and the middle-slope was: the roots>the branches and leaves>the deadwood and defoliation, but in the down-slope, the sequence was: the branches and the leaves >the roots >the deadwood and the defoliation. (5) The ratio between the percentage of the above-ground biomass and the root biomass in the herbage layer total biomass gradually increase from the upper-slope to the down-slope in sloping-land with purple soils in Hengyang basin.