| In this paper, the 30 years old artificial Caragana korshinskill population were taken as the research object in the gullied Loess Plateau, and growth, reproductive and regeneration characteristics,dry matter allocation,community structure were studied at different site conditions in the hilly regions of loess plateau, and to evaluate the plantation communities naturalized development, to provide theoretical bases for planting and management.The main results were as follows:(1)In the gullied loess plateaus,the flowering,fruiting and seeds scattering of artificial Caragana korshinskill populations are normal,and the seed yield are relatively high.But after the seeds fallen,there are little to settle,the sexual reproduction is difficult to maintain the population regeneration in this region.Light has a positive impact on Caragana korshinskill, but water is a key factor which limits the seed germination grow into seedling.(2) The natural regeneration of artificial Caragana korshinskill populations mainly depend on root sucker and root sprout after stumping, they are both produced by the asexual propagation of stock plant. The asexual propagation of Caragana korshinskill in this region exists as three styles: sprouts germinating from stump,sprouts germinating from main root and sprouts germinating from root system. In comparison of different habitats, the number of cloned seedling showed that the half-sunny slope (1863.5 sprout/100m2) > the sunny slope (1641.9 sprout/100m2 ) > hilltop (1587.3 sprout/100m2 ) > the half-shady slope (1119.7 sprout/100m2 ) > the shady slope (1091.1 sprout/100m2 ), but the growth status of cloned seedling showed that the shady slope>the half-shady slope> the half-sunny slope> the sunny slope>the hilltop; The root germination point of Caragana korshinskill was concentrated between 10~30 cm, and the extended distance showed that the sunny slope(1.16 m)> the half-sunny slope(0.96 m)﹥the hilltop(0.88 m)﹥the half-shady slope(0.75 m)﹥the shady slope(0.66 m).(3) The comparison results of total clonal dry weight of standard plants of 30 a artificial Caragana korshinskill population in different habitats as follows: the shady slope(3.325 kg) >the half-shady slope(3.114 kg) > the half-sunny slope(2.911 kg) > the sunny slope(2.792 kg) >the hilltop(2.680 kg); the root-shoot ratio of standard plants are: the hilltop (0.710:1) > the sunny slope (0.611:1) > the half-sunny slope (0.523:1) > the half-shady slope (0.399:1) > the shady slope(0.340:1). These show that the artificial Caragana korshinskill population in the gullied loess plateaus through the way of reducing the dry weight of stems and leaves on the ground and expanding the underground root system to adapt to arid environments.(4) Through comparison study the age structure and community species diversity, the result showed that artificial C.korshinskii population in the region belonged to progressive type,with more young and less old individuals. The survival curve of them was approached to DeeveyⅡtype. There were 44 species of seed plants in C.korshinskii community. The community diversity index showed the status of the shady slope >the half-shady slope>the half-sunny slope>the sunny slope>the hilltop. Water, light, soil organic matter and human interferences were the main environmental factors affecting the recovery and development of C.korshinskii community.(5) Based on fuzzy membership function synthetic evaluation model, the plantation community naturalized development was evaluated.The result show that the half-sunny slope>the half-shady slope>the shady slope>the sunny slope>the hilltop.(6) In the future business process management of the artificial Caragana korshinskill population, Every seven years time as a cycle for stumping,improve the suckering ability of Caragana korshinskill, meanwhile, In the initial stage of the community formation, the artificial tending of the population and structure improvement of the community are the main mensures and ways to the goals of natural regeneration and growth. |
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