The cultivated land-water resources carrying capacity(CL-WRCC)with the method of system dynamics(SD)were analyzed.Bijie prefecture of Guizhou province served as a case in this study.Bijie prefecture is one of the leas...The cultivated land-water resources carrying capacity(CL-WRCC)with the method of system dynamics(SD)were analyzed.Bijie prefecture of Guizhou province served as a case in this study.Bijie prefecture is one of the least-developed areas in China.In Bijie,the physical and chemical characteristics of karst as well as the rapid economic development lead to the scarcities of cultivated land-water resources(CL-WR).On the basis of analysis on the subsystems of Bijie CL-WRCC system,the fundamental feedback structure of CL-WRCC was presented by causal loop diagram.Considering the three aims("poverty alleviation and development,ecological construction,and population control")of Bijie as the major goals,Bijie CL-WRCC SD model was developed.Three scenarios,resource-saving and environment-friendly development-oriented scenario(Scenario 1),fast economic development-oriented scenario(Scenario 2),and coordinated development-oriented scenario(Scenario 3),were investigated.Simulation results indicate that Scenario 3 which takes social economic development,environment protection,and cultivated landwater resources utilization into account,is the best alternative scenario.It can promote the coordination development of society,economy,cultivated land,water resources,and environment.In this study,the technological support and the decision-making for the rational use of CL-WR are provided not only in Bijie,but also in other similar regions of China.展开更多
Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zon...Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zones （ALWTZs） of shallow lakes. In this study, decomposition experiments on 1- to 6-year-old R australis rhizomes were conducted in the ALWTZ of Lake Baiyangdian to evaluate the contribution of the rhizomes to organic matter accumulation and nutrient release. Mass loss and changes in nutrient content were measured after 3, 7, 15, 30, 60, 90, 120, and 180 days. The decomposition process was modeled with a composite exponential model. The Pearson correlation analysis was used to analyze the relationships between mass loss and litter quality factors. A multiple stepwise regression model was utilized to determine the dominant factors that affect mass loss. Results showed that the decomposition rates in water were significantly higher than those in soil for 1- to 6-year-old rhizomes. However, the sequence of decomposition rates was identical in both water and soil. Significant relationships between mass loss and litter quality factors were observed at a later stage, and P-related factors proved to have a more significant impact than N-related factors on mass loss. According to multiple stepwise models, the C/P ratio was found to be the dominant factor affecting the mass loss in water, and the C/N and C/P ratios were the main factors affecting the mass loss in soil. The combined effects of harvesting, ditch broadening, and control of water depth should be considered for lake administrators.展开更多
基金Knowledge Innovation Project of Chinese Academy of Sciences(CAS),China(No.KZCX2-YW-333)
文摘The cultivated land-water resources carrying capacity(CL-WRCC)with the method of system dynamics(SD)were analyzed.Bijie prefecture of Guizhou province served as a case in this study.Bijie prefecture is one of the least-developed areas in China.In Bijie,the physical and chemical characteristics of karst as well as the rapid economic development lead to the scarcities of cultivated land-water resources(CL-WR).On the basis of analysis on the subsystems of Bijie CL-WRCC system,the fundamental feedback structure of CL-WRCC was presented by causal loop diagram.Considering the three aims("poverty alleviation and development,ecological construction,and population control")of Bijie as the major goals,Bijie CL-WRCC SD model was developed.Three scenarios,resource-saving and environment-friendly development-oriented scenario(Scenario 1),fast economic development-oriented scenario(Scenario 2),and coordinated development-oriented scenario(Scenario 3),were investigated.Simulation results indicate that Scenario 3 which takes social economic development,environment protection,and cultivated landwater resources utilization into account,is the best alternative scenario.It can promote the coordination development of society,economy,cultivated land,water resources,and environment.In this study,the technological support and the decision-making for the rational use of CL-WR are provided not only in Bijie,but also in other similar regions of China.
文摘Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zones （ALWTZs） of shallow lakes. In this study, decomposition experiments on 1- to 6-year-old R australis rhizomes were conducted in the ALWTZ of Lake Baiyangdian to evaluate the contribution of the rhizomes to organic matter accumulation and nutrient release. Mass loss and changes in nutrient content were measured after 3, 7, 15, 30, 60, 90, 120, and 180 days. The decomposition process was modeled with a composite exponential model. The Pearson correlation analysis was used to analyze the relationships between mass loss and litter quality factors. A multiple stepwise regression model was utilized to determine the dominant factors that affect mass loss. Results showed that the decomposition rates in water were significantly higher than those in soil for 1- to 6-year-old rhizomes. However, the sequence of decomposition rates was identical in both water and soil. Significant relationships between mass loss and litter quality factors were observed at a later stage, and P-related factors proved to have a more significant impact than N-related factors on mass loss. According to multiple stepwise models, the C/P ratio was found to be the dominant factor affecting the mass loss in water, and the C/N and C/P ratios were the main factors affecting the mass loss in soil. The combined effects of harvesting, ditch broadening, and control of water depth should be considered for lake administrators.
