[Objective] The aim was to explore the species diversity of flower-visiting Syrphidae in the farmland of Hanzhong area.[Method] Based on the sample collection and the sorting and identification of collected specimens ...[Objective] The aim was to explore the species diversity of flower-visiting Syrphidae in the farmland of Hanzhong area.[Method] Based on the sample collection and the sorting and identification of collected specimens and literature,the species and their seasonal changes of flower-visiting Syrphidae in the agroecosystem of Hanzhong area were systematically analyzed.[Result] 5 015 specimens of Syrphidae were cheaked in this study,and 141 species of 53 genera of 16 families in three subfamilies of flower-visiting species of Syrphidae were identified in farmland of Hanzhong area,in which 65 species were Syrphinae;72 species were Milesiinae;while four species were Microdontinae.The species of Syrphidae in this region were active in April,May,June and July.There were two dominant species in this region,including Episyrphus balteatus and Eristalis tenax.[Conclusion] This study had provided theoretical basis for the studies on the flower-visiting habit and fecundation of insects of Syrphidae in this area.展开更多
A new species in the genus Austrohancockia Gtinther, Austrohancockia undatimarginis Deng ＆ Zheng sp. nov. is described from Damingshan National Nature Reserve in Guangxi, China. The type specimens are deposited in th...A new species in the genus Austrohancockia Gtinther, Austrohancockia undatimarginis Deng ＆ Zheng sp. nov. is described from Damingshan National Nature Reserve in Guangxi, China. The type specimens are deposited in the Institute of Zoology, Shaanxi Normal University, Xi＇an, China.展开更多
Small-scale household agricultural production has been in conflict with China＇s agricultural modernization.In the context of vigorously promoting rural land circulation and moderate scale management nationwide,resear...Small-scale household agricultural production has been in conflict with China＇s agricultural modernization.In the context of vigorously promoting rural land circulation and moderate scale management nationwide,research on the relationship between farm size and scale efficiency has become increasingly important.In this paper,we use the ＂DEA-OLS＂ two stage method to analyze data from 368 surveys of rice farming households in the Jianghan Plain.The scale efficiency of rice farming was calculated,and the relationship between farm size and scale efficiency investigated.The results indicate that（1） the rice farm size is generally small in Jianghan Plain,with an average of 0.77 ha.The average scale efficiency is 0.88,and it is the main factor limiting an increase in comprehensive technical efficiency.Moreover,88.32% of households are in the stage of increasing returns to scale.（2） There is a stable inverted ＂U＂ type relationship between rice farm size and scale efficiency.Considering characteristics of the householder,the household and land quality,the maximum scale efficiency corresponds to a household with 5 ha of rice farm.（3） Among householder characteristics,age has a significant negative influence on scale efficiency,and scale efficiency is lower for a household whose householder is engaged in non-farm work than for one whose householder is devoted to farming.As for land quality,there was a significant positive effect of irrigation on scale efficiency.Among family characteristics,the application of a machine during the seeding process increased scale efficiency by 3.07%.Therefore,we suggest that local government should actively promote rural land circulation,implement a staged-scale management subsidy,and other forms of support for the purchase of agricultural machinery and technical popularization.Increased investment in irrigation improvements and mechanical facilities and encouragement of farmers to enlarge their farm size could improve scale efficiency and farming profit and lead to the development of moderate scale management.展开更多
基金Supported by National Natural Science Foundation of China(31071966)Natural Science Foundation of Shaanxi Province(2009JM3007)Innovative Research Projects for Students in Shaanxi University of Technology~~
文摘[Objective] The aim was to explore the species diversity of flower-visiting Syrphidae in the farmland of Hanzhong area.[Method] Based on the sample collection and the sorting and identification of collected specimens and literature,the species and their seasonal changes of flower-visiting Syrphidae in the agroecosystem of Hanzhong area were systematically analyzed.[Result] 5 015 specimens of Syrphidae were cheaked in this study,and 141 species of 53 genera of 16 families in three subfamilies of flower-visiting species of Syrphidae were identified in farmland of Hanzhong area,in which 65 species were Syrphinae;72 species were Milesiinae;while four species were Microdontinae.The species of Syrphidae in this region were active in April,May,June and July.There were two dominant species in this region,including Episyrphus balteatus and Eristalis tenax.[Conclusion] This study had provided theoretical basis for the studies on the flower-visiting habit and fecundation of insects of Syrphidae in this area.
基金supported by the National Natural Science Foundation of China (31160433)the Beibu Gulf Major Project of the Guangxi Natural Science Foundation (2010GXNSFE013004)the Guangxi Natural Science Foundation (0991266)
文摘A new species in the genus Austrohancockia Gtinther, Austrohancockia undatimarginis Deng ＆ Zheng sp. nov. is described from Damingshan National Nature Reserve in Guangxi, China. The type specimens are deposited in the Institute of Zoology, Shaanxi Normal University, Xi＇an, China.
基金National Natural Science Foundation of China(41571095)
文摘Small-scale household agricultural production has been in conflict with China＇s agricultural modernization.In the context of vigorously promoting rural land circulation and moderate scale management nationwide,research on the relationship between farm size and scale efficiency has become increasingly important.In this paper,we use the ＂DEA-OLS＂ two stage method to analyze data from 368 surveys of rice farming households in the Jianghan Plain.The scale efficiency of rice farming was calculated,and the relationship between farm size and scale efficiency investigated.The results indicate that（1） the rice farm size is generally small in Jianghan Plain,with an average of 0.77 ha.The average scale efficiency is 0.88,and it is the main factor limiting an increase in comprehensive technical efficiency.Moreover,88.32% of households are in the stage of increasing returns to scale.（2） There is a stable inverted ＂U＂ type relationship between rice farm size and scale efficiency.Considering characteristics of the householder,the household and land quality,the maximum scale efficiency corresponds to a household with 5 ha of rice farm.（3） Among householder characteristics,age has a significant negative influence on scale efficiency,and scale efficiency is lower for a household whose householder is engaged in non-farm work than for one whose householder is devoted to farming.As for land quality,there was a significant positive effect of irrigation on scale efficiency.Among family characteristics,the application of a machine during the seeding process increased scale efficiency by 3.07%.Therefore,we suggest that local government should actively promote rural land circulation,implement a staged-scale management subsidy,and other forms of support for the purchase of agricultural machinery and technical popularization.Increased investment in irrigation improvements and mechanical facilities and encouragement of farmers to enlarge their farm size could improve scale efficiency and farming profit and lead to the development of moderate scale management.
