Desertification is the most serious environmental problem in the world today. Fractal feature of granularity composition was studied by using the fractal theory in view of desertification soil in Fuxin district, there...Desertification is the most serious environmental problem in the world today. Fractal feature of granularity composition was studied by using the fractal theory in view of desertification soil in Fuxin district, thereby evolution patterns of desertification was promulgated. The result shows that the self-formation degree of the developing desertification areas is higher than the relatively steady desertification areas. Evolution of desertification is beginning of forming sandy soil of framework composition, and then the sandy soil be came complex by the effect of environment, climate and anthropo-activity.展开更多
Approximately 331 million ha, one-third of China＇s total land, is prone to desertification processes, leading to natural disasters and economic losses. In this study, the situation, tendency, their influences and the...Approximately 331 million ha, one-third of China＇s total land, is prone to desertification processes, leading to natural disasters and economic losses. In this study, the situation, tendency, their influences and their risk governance of desertification and blown sand disaster in China were examined using satellite images, field photographs, field data and a literature review. The desiccated areas in Lop Nor and the lower Heihe River fluvial plain covered about 50,000 km2 and 40,000 km2, respectively. In Ejina, about 100 species of vegetation became extinct. The rate of wind erosion in China was between 1,000 tons/km2/year and 2,000 tons/km2/year. There were 12 sand deserts and sandy lands, occupying a total of 710,000 km2. Salinized soils occurred across 99.1 million ha. The two main sand and dust storm-prone areas in China were the Tarim Basin and its surroundings, and the Alxa Plateau and its surroundings. From 1981 to 2007, the annual average frequency of sand and dust storms varied from 1 d to 37 d with a general increase from southeast to northwest. Since 1978, China has implemented a number of ecological construction projects that have reduced desertification from 1999 to 2004 and from 2005 to 2009, and the number of dust and sand storm days from 9.3 d between 1954 and 1959 to 4.4 d between 2000 and 2007. The results could improve understanding of desertification and blown sand disasters in China and provide valuable experiences for global desertification control.展开更多
According to a long series of measured sediment data, the sedimentation effects of the Dongting Lake Area （DIP,） were studied in light of the relationship between sedimentation characteristics and resources and envi...According to a long series of measured sediment data, the sedimentation effects of the Dongting Lake Area （DIP,） were studied in light of the relationship between sedimentation characteristics and resources and environment. The result shows that the long-term deposition and the impact of human activities have led to a cycle of the evolution of sedimentation pattern, resulting in sediment disaster effects and resources effects in the DLA. The main features are as follows： 1） The water beach, silt beach, lake marsh beach, reed beach and other types of beach shaped by sedimentation effects constitute the main body of the giant lake system. 2） The disaster chains are induced, i.e., sedimentation → marshland expansion and reclamation → flood function decline, fish resource depletion, biodiversity reduction dis- aster chain, sedimentation → marshland expansion → floods, water pollution disaster chain, sedimentation → marshland floating vegetation rising → schistosomiasis, rodents virulence disaster chain, sedimentation → flood embankment bursting → land desertification disaster chain. 3） Sedimentation has created about 98.13×10^4 hm^2 of land in the past 55 years. Rational development and utilization of marshland resources have produced tremendous economic benefits.展开更多
The study focused on one of the important contemporary environmental problems, land deterioration, carried out on a semi-desert rangeland constrained by aridity, in an area stretching between two small cities （Solouk...The study focused on one of the important contemporary environmental problems, land deterioration, carried out on a semi-desert rangeland constrained by aridity, in an area stretching between two small cities （Solouk and A1-Abyar） south of the city of Benghazi in north eastern Libya. The vegetation analysis revealed that the plant life is mainly confined to wadis （valleys）. Average vegetation cover was ranging between 39.53% and 69.20%. Biomass was ranging between 28.33 gm/m2 and 129.42 gm/m2, （average soil depth was between 30 cm and 50 cm）, meanwhile 25% of the area is covered by hummocks. The total number of sampled soil seed bank was 25,870 seed/m2, in which the important forage family Fabaceae constituted 450 seed/m2. Life forms spectrum was： 55.2% Therophytes, 26.3% Chamaeopytes, 11.4% Cryptophytes and 7.1% Phanerophytes. Alpha diversity 1.3%-3.4%, and Beta diversity 11.9%-77.6%. The soil showed low organic matter content an lean to alkalinity. The study showed that the area is characterized by harsh climate elements which led to land degradation in the form of low productivity, retrogressive succession, soil erosion, and sandy encroachment from the south desert area. In the last decades the land degradation was accelerated by the accumulative anthropogenic.展开更多
文摘Desertification is the most serious environmental problem in the world today. Fractal feature of granularity composition was studied by using the fractal theory in view of desertification soil in Fuxin district, thereby evolution patterns of desertification was promulgated. The result shows that the self-formation degree of the developing desertification areas is higher than the relatively steady desertification areas. Evolution of desertification is beginning of forming sandy soil of framework composition, and then the sandy soil be came complex by the effect of environment, climate and anthropo-activity.
文摘Approximately 331 million ha, one-third of China＇s total land, is prone to desertification processes, leading to natural disasters and economic losses. In this study, the situation, tendency, their influences and their risk governance of desertification and blown sand disaster in China were examined using satellite images, field photographs, field data and a literature review. The desiccated areas in Lop Nor and the lower Heihe River fluvial plain covered about 50,000 km2 and 40,000 km2, respectively. In Ejina, about 100 species of vegetation became extinct. The rate of wind erosion in China was between 1,000 tons/km2/year and 2,000 tons/km2/year. There were 12 sand deserts and sandy lands, occupying a total of 710,000 km2. Salinized soils occurred across 99.1 million ha. The two main sand and dust storm-prone areas in China were the Tarim Basin and its surroundings, and the Alxa Plateau and its surroundings. From 1981 to 2007, the annual average frequency of sand and dust storms varied from 1 d to 37 d with a general increase from southeast to northwest. Since 1978, China has implemented a number of ecological construction projects that have reduced desertification from 1999 to 2004 and from 2005 to 2009, and the number of dust and sand storm days from 9.3 d between 1954 and 1959 to 4.4 d between 2000 and 2007. The results could improve understanding of desertification and blown sand disasters in China and provide valuable experiences for global desertification control.
基金Key Discipline Building Program on Physical Geography of Hunan ProvinceProject for Science & Tech-nology of Hunan Province,No.2007Fj302
文摘According to a long series of measured sediment data, the sedimentation effects of the Dongting Lake Area （DIP,） were studied in light of the relationship between sedimentation characteristics and resources and environment. The result shows that the long-term deposition and the impact of human activities have led to a cycle of the evolution of sedimentation pattern, resulting in sediment disaster effects and resources effects in the DLA. The main features are as follows： 1） The water beach, silt beach, lake marsh beach, reed beach and other types of beach shaped by sedimentation effects constitute the main body of the giant lake system. 2） The disaster chains are induced, i.e., sedimentation → marshland expansion and reclamation → flood function decline, fish resource depletion, biodiversity reduction dis- aster chain, sedimentation → marshland expansion → floods, water pollution disaster chain, sedimentation → marshland floating vegetation rising → schistosomiasis, rodents virulence disaster chain, sedimentation → flood embankment bursting → land desertification disaster chain. 3） Sedimentation has created about 98.13×10^4 hm^2 of land in the past 55 years. Rational development and utilization of marshland resources have produced tremendous economic benefits.
文摘The study focused on one of the important contemporary environmental problems, land deterioration, carried out on a semi-desert rangeland constrained by aridity, in an area stretching between two small cities （Solouk and A1-Abyar） south of the city of Benghazi in north eastern Libya. The vegetation analysis revealed that the plant life is mainly confined to wadis （valleys）. Average vegetation cover was ranging between 39.53% and 69.20%. Biomass was ranging between 28.33 gm/m2 and 129.42 gm/m2, （average soil depth was between 30 cm and 50 cm）, meanwhile 25% of the area is covered by hummocks. The total number of sampled soil seed bank was 25,870 seed/m2, in which the important forage family Fabaceae constituted 450 seed/m2. Life forms spectrum was： 55.2% Therophytes, 26.3% Chamaeopytes, 11.4% Cryptophytes and 7.1% Phanerophytes. Alpha diversity 1.3%-3.4%, and Beta diversity 11.9%-77.6%. The soil showed low organic matter content an lean to alkalinity. The study showed that the area is characterized by harsh climate elements which led to land degradation in the form of low productivity, retrogressive succession, soil erosion, and sandy encroachment from the south desert area. In the last decades the land degradation was accelerated by the accumulative anthropogenic.
