In the research, reform of rural collective economy property right system in Beijing rural-urban continuum was explored in terms of background, cause, pro- cess and practice modes by surveying and interviewing, and th...In the research, reform of rural collective economy property right system in Beijing rural-urban continuum was explored in terms of background, cause, pro- cess and practice modes by surveying and interviewing, and the value of system reform on urbanization in rural areas was illustrated from the perspective of farmers who lose lands. The results showed that since reform and opening-up, disadvan- tages of collective economy property are always the fundamental cause of reform; rural-urban contradiction produced from rapid urbanization makes the reform much more urgent; shareholding co-operative system is the essence of reform of collective economy property right system. Rural collective economy property right system in Beijing includes stock-assets quantification shareholding co-operative system, share- capitalization of contractual land management right, farmers as shareholders by investment, and resource and capital mode, with advantages and disadvantages respectively. The common character should be noticed is that all modes have share on contractual right of land, indicating the core of the reform of property system lies in asset quantification and stock quota. In improving urban-rural integration and modern market system, as well as endowing more rights to farmers, reform of rural collective economy property right system is of great significance, which provides a transition space and buffer mechanism for urbanization in rural areas.展开更多
Soil salinity is the most important factor affecting vegetation distribution,and the secondary salinization has affected the development of oasis agriculture.In arid areas the spatial variation of soil moisture and sa...Soil salinity is the most important factor affecting vegetation distribution,and the secondary salinization has affected the development of oasis agriculture.In arid areas the spatial variation of soil moisture and sa lt content is marked-ly affected by groundwater,irratio nal irrigation in artificial oasis.By analyzing the soil moisture,salt content and groundwa-ter table in different areas of old oasis,new oasis and desert in Fukang Oa sis,it is shown that topography and l and use are main factors affecting the change of groundwater table,the redistribution of soil moisture and salt cont ent.When undis-turbed by human,the groundwater tab le rises from mountain to belt of grou nd water spillage,the groundwater t able rises mightily in plain because of the artificial irrigation,and the secondary salinization of soil is very seriou s.In oasis the ground-water table raises compared with that in the natural desert at the same latitude.In old oasis of upper reaches o f river salt has not been concentrated too much in rhizosphere because this area is the belt of groundwater drainage,soil t exture is coarse,the groundwater table is very low,and the salt in soil is drained i nto the groundwater.The new oasis has been the areas of salt accumulation becau se of the artificial irrigation,the salt content in soil is higher than th at in old oasis,so some cultivated fields here had to be thrown out because of the serious s econdary salinization.展开更多
Sound pond productivity accompanied with adequate fish health is maintained, when water quality parameters are conducive. The study evaluated the chemical composition of a pond feed from spring water, in Asaba Campus....Sound pond productivity accompanied with adequate fish health is maintained, when water quality parameters are conducive. The study evaluated the chemical composition of a pond feed from spring water, in Asaba Campus. Sampling was carried out from September 2011 to February 2012 on a monthly basis. Surface water samples were collected between the hours of 7：00-9：00 am from the pond on each sampling day. Hydrogen-ion-concentration was in the range of 6.5 to 8.0 units. Dissolved oxygen was the highest in February 2012 with a value of 11.0 mg/L while it was the lowest in December 2011 with a value of 9.0 mg/L. Biological oxygen demand ranged from 3.5 to 5.0 mg/L. The chemical oxygen demand was the highest in December （10.00 mg/L） and lowest between January and February （8.0mg/L）. The highest alkalinity was observed in October with a value of 1.05 mg/L and lowest in December with a value of 0.042 mg/L. Conductivity values ranged from 0.075 to 0.12 μS/cm. Total phosphorus was the highest in October with a value of 1.01 mg/L and lowest in December with a value of 0.83 mg/L. Total dissolved solids ranged from 90 to 105 mg/L. Values of physco-chemical parameters revealed that the pond was not polluted. Water quality analysis of the aquatics is of economic advantage to the fish farmer, hence, the need for its assessment at regular intervals. This is a quality assurance process that assures early dictation of toxic substances and mitigation processes to adopt before problems arise. In this way, the good health of organisms in the aquatic ecosystem and those of human dependent on them are guaranteed.展开更多
The role of organic matter in the formation and stability of soil aggregates in mulberry plantation in the Hang-Jia-Hu Plain, northern Zhejiang Province, was evaluated in this study. A positive correlation was found b...The role of organic matter in the formation and stability of soil aggregates in mulberry plantation in the Hang-Jia-Hu Plain, northern Zhejiang Province, was evaluated in this study. A positive correlation was found between water-stable aggregate contents and organic matter contents in the mulberry plantation soils, which supported the hypothesis that organic matter was the main cementing agent in formation of aggregates. A close correlation was also found between stability of aggregate and organic matter contents. Regression analysis showed that total nitrogen content was also an indicator of water-stable aggregate content and stability. The aggregate size distribution indicated that the water-stable aggregates 1--0.25 mm in diameter were the major component of the aggregates in the mulberry plantation soils. The organic matter contents of aggregates ranging from 5 to 0.25 mm in diameter increased with the decrease of aggregate sizes, and the aggregates 1-0.25 mm in diameter had the maximum organic matter content.展开更多
基金Supported by Major Project of the National Social Science Fund(13&ZD027)National Natural Science Foundation of China(41371177)the National Science and Technology Support Planning(2012BAJ22B03)~~
文摘In the research, reform of rural collective economy property right system in Beijing rural-urban continuum was explored in terms of background, cause, pro- cess and practice modes by surveying and interviewing, and the value of system reform on urbanization in rural areas was illustrated from the perspective of farmers who lose lands. The results showed that since reform and opening-up, disadvan- tages of collective economy property are always the fundamental cause of reform; rural-urban contradiction produced from rapid urbanization makes the reform much more urgent; shareholding co-operative system is the essence of reform of collective economy property right system. Rural collective economy property right system in Beijing includes stock-assets quantification shareholding co-operative system, share- capitalization of contractual land management right, farmers as shareholders by investment, and resource and capital mode, with advantages and disadvantages respectively. The common character should be noticed is that all modes have share on contractual right of land, indicating the core of the reform of property system lies in asset quantification and stock quota. In improving urban-rural integration and modern market system, as well as endowing more rights to farmers, reform of rural collective economy property right system is of great significance, which provides a transition space and buffer mechanism for urbanization in rural areas.
文摘Soil salinity is the most important factor affecting vegetation distribution,and the secondary salinization has affected the development of oasis agriculture.In arid areas the spatial variation of soil moisture and sa lt content is marked-ly affected by groundwater,irratio nal irrigation in artificial oasis.By analyzing the soil moisture,salt content and groundwa-ter table in different areas of old oasis,new oasis and desert in Fukang Oa sis,it is shown that topography and l and use are main factors affecting the change of groundwater table,the redistribution of soil moisture and salt cont ent.When undis-turbed by human,the groundwater tab le rises from mountain to belt of grou nd water spillage,the groundwater t able rises mightily in plain because of the artificial irrigation,and the secondary salinization of soil is very seriou s.In oasis the ground-water table raises compared with that in the natural desert at the same latitude.In old oasis of upper reaches o f river salt has not been concentrated too much in rhizosphere because this area is the belt of groundwater drainage,soil t exture is coarse,the groundwater table is very low,and the salt in soil is drained i nto the groundwater.The new oasis has been the areas of salt accumulation becau se of the artificial irrigation,the salt content in soil is higher than th at in old oasis,so some cultivated fields here had to be thrown out because of the serious s econdary salinization.
文摘Sound pond productivity accompanied with adequate fish health is maintained, when water quality parameters are conducive. The study evaluated the chemical composition of a pond feed from spring water, in Asaba Campus. Sampling was carried out from September 2011 to February 2012 on a monthly basis. Surface water samples were collected between the hours of 7：00-9：00 am from the pond on each sampling day. Hydrogen-ion-concentration was in the range of 6.5 to 8.0 units. Dissolved oxygen was the highest in February 2012 with a value of 11.0 mg/L while it was the lowest in December 2011 with a value of 9.0 mg/L. Biological oxygen demand ranged from 3.5 to 5.0 mg/L. The chemical oxygen demand was the highest in December （10.00 mg/L） and lowest between January and February （8.0mg/L）. The highest alkalinity was observed in October with a value of 1.05 mg/L and lowest in December with a value of 0.042 mg/L. Conductivity values ranged from 0.075 to 0.12 μS/cm. Total phosphorus was the highest in October with a value of 1.01 mg/L and lowest in December with a value of 0.83 mg/L. Total dissolved solids ranged from 90 to 105 mg/L. Values of physco-chemical parameters revealed that the pond was not polluted. Water quality analysis of the aquatics is of economic advantage to the fish farmer, hence, the need for its assessment at regular intervals. This is a quality assurance process that assures early dictation of toxic substances and mitigation processes to adopt before problems arise. In this way, the good health of organisms in the aquatic ecosystem and those of human dependent on them are guaranteed.
基金Project supported by Earthwatch, USA and the Laboratory of Material Cycling in Pedosphere, the ChineseAcademy of Sciences.
文摘The role of organic matter in the formation and stability of soil aggregates in mulberry plantation in the Hang-Jia-Hu Plain, northern Zhejiang Province, was evaluated in this study. A positive correlation was found between water-stable aggregate contents and organic matter contents in the mulberry plantation soils, which supported the hypothesis that organic matter was the main cementing agent in formation of aggregates. A close correlation was also found between stability of aggregate and organic matter contents. Regression analysis showed that total nitrogen content was also an indicator of water-stable aggregate content and stability. The aggregate size distribution indicated that the water-stable aggregates 1--0.25 mm in diameter were the major component of the aggregates in the mulberry plantation soils. The organic matter contents of aggregates ranging from 5 to 0.25 mm in diameter increased with the decrease of aggregate sizes, and the aggregates 1-0.25 mm in diameter had the maximum organic matter content.
