On the basis of the soil environment investigation in Da＇an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter （SOM）, total N （TN...On the basis of the soil environment investigation in Da＇an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter （SOM）, total N （TN）, total P （TP）, total K （TK）, available N （AN）, available P （AP） and available K （AK） were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da＇an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.展开更多
Quantitative assessment of vulnerability is a core aspect of wetland vulnerability research.Taking Baiyangdian(BYD)wetlands in the North China Plain as a study area and using the‘cause-result’model,23 representative...Quantitative assessment of vulnerability is a core aspect of wetland vulnerability research.Taking Baiyangdian(BYD)wetlands in the North China Plain as a study area and using the‘cause-result’model,23 representative indicators from natural,social,sci-tech and economic elements were selected to construct an indicator system.A weight matrix was obtained by using the entropy weight method to calculate the weight value for each indicator.Based on the membership function in the fuzzy evaluation model,the membership degrees were determined to form a fuzzy relation matrix.Finally,the ecological vulnerability was quantitatively assessed based on the comprehensive evaluation index calculated by using a composite operator to combine the entropy weight matrix with the fuzzy relation matrix.The results showed that the ecological vulnerability levels of the BYD wetlands were comprehensively evaluated as Grade Ⅱ,Grade Ⅲ,Grade Ⅳ,and Grade Ⅲ in 2010,2011-2013,2014,and 2015-2017,respectively.The ecological vulnerability of the BYD wetlands increased from low fragility in 2010 to general fragility in 2011-2013,and to high fragility in 2014,reflecting the fact that the wetland ecological condition was degenerating from 2010 to 2014.The ecological vulnerability status then turned back into general fragility during 2015-2017,indicating that the ecological situation of the BYD wetlands was starting to improve.However,the ecological status of the BYD wetlands on the whole is relatively less optimistic.The major factors affecting the ecological vulnerability of the BYD wetlands were found to be industrial smoke and dust emission,wetland water area,ammonia nitrogen,total phosphorus,rate of industrial solid wastes disposed,GDP per capita,etc.This illustrates that it is a systematic project to regulate wetland vulnerability and to protect regional ecological security,which may offer researchers and policy-makers specific clues for concrete interventions.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 40572170, 40871088 )
文摘On the basis of the soil environment investigation in Da＇an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter （SOM）, total N （TN）, total P （TP）, total K （TK）, available N （AN）, available P （AP） and available K （AK） were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da＇an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.
基金The Key Research and Development Project by Science and Technology Program of Hebei(18273005)。
文摘Quantitative assessment of vulnerability is a core aspect of wetland vulnerability research.Taking Baiyangdian(BYD)wetlands in the North China Plain as a study area and using the‘cause-result’model,23 representative indicators from natural,social,sci-tech and economic elements were selected to construct an indicator system.A weight matrix was obtained by using the entropy weight method to calculate the weight value for each indicator.Based on the membership function in the fuzzy evaluation model,the membership degrees were determined to form a fuzzy relation matrix.Finally,the ecological vulnerability was quantitatively assessed based on the comprehensive evaluation index calculated by using a composite operator to combine the entropy weight matrix with the fuzzy relation matrix.The results showed that the ecological vulnerability levels of the BYD wetlands were comprehensively evaluated as Grade Ⅱ,Grade Ⅲ,Grade Ⅳ,and Grade Ⅲ in 2010,2011-2013,2014,and 2015-2017,respectively.The ecological vulnerability of the BYD wetlands increased from low fragility in 2010 to general fragility in 2011-2013,and to high fragility in 2014,reflecting the fact that the wetland ecological condition was degenerating from 2010 to 2014.The ecological vulnerability status then turned back into general fragility during 2015-2017,indicating that the ecological situation of the BYD wetlands was starting to improve.However,the ecological status of the BYD wetlands on the whole is relatively less optimistic.The major factors affecting the ecological vulnerability of the BYD wetlands were found to be industrial smoke and dust emission,wetland water area,ammonia nitrogen,total phosphorus,rate of industrial solid wastes disposed,GDP per capita,etc.This illustrates that it is a systematic project to regulate wetland vulnerability and to protect regional ecological security,which may offer researchers and policy-makers specific clues for concrete interventions.
