The application model of epidemic disease assessment technology for Web-based large-scale pig farm was expounded from the identification of epidemic disease risk factors, construction of risk assessment model and deve...The application model of epidemic disease assessment technology for Web-based large-scale pig farm was expounded from the identification of epidemic disease risk factors, construction of risk assessment model and development of risk assessment system. The assessed pig farm uploaded the epidemic disease risk data information through on-line answering evaluating questionnaire to get the immediate evaluation report. The model could enhance the risk communication between pig farm veterinarian, manager and veterinary experts to help farm system understand and find disease risk factors, assess and report the potential high risk items of the pig farm in the three systems of engineering epidemic disease prevention technology, biological safety and immune monitoring, and promote the improvement and perfection of epidemic disease prevention and control measures.展开更多
Large-scale breeding of livestock and poultry is the main way of modern animal husbandry development.This breeding method is widely used by the majority of owners because of its easy technical promotion,low breeding c...Large-scale breeding of livestock and poultry is the main way of modern animal husbandry development.This breeding method is widely used by the majority of owners because of its easy technical promotion,low breeding cost and good economic benefits.But with the development of large-scale livestock and poultry breeding,the pollution and damage to the environment caused by fecal pollution from large-scale livestock and poultry breeding has been criticized by many environmentalists.In this paper,through visit and investigation of large-scale livestock and poultry farms,the methods and measures of environmental protection in the construction of large-scale livestock and poultry farms are proposed.展开更多
[Objective]The paper was to analyze the pathogenesis of Escherichia coli O123 from rex rabbit. [Method]E. coli O123 isolated from rabbit liver with diarrhea symptom in scale rex rabbit farm was intraperitoneally injec...[Objective]The paper was to analyze the pathogenesis of Escherichia coli O123 from rex rabbit. [Method]E. coli O123 isolated from rabbit liver with diarrhea symptom in scale rex rabbit farm was intraperitoneally injected into 18- 22 g Kunming mice,and its pathogenicity was determined by clinical symptoms and pathological examination. [Result]When the inoculation concentration was about 8. 5 × 107 CFU /mL,Kunming mice appeared the clinical symptoms of drooping spirit,diarrhea and gathering,and the mortality reached 50%. Anatomical examination found that intestinal wall was thinning and intestinal mucosa was bleeding. [Conclusion]E. coli from rex rabbit has strong pathogenicity,and establishing animal model with Kunming mice to study its pathogenesis is of great reference significance for diagnosis and prevention of E. coli disease of rex rabbit.展开更多
The Chinese Government has increased its focus on expanding farm scale to promote agricultural development since 2010. A series of favorable polices has been adopted to support large-scale farming. Using a multivariat...The Chinese Government has increased its focus on expanding farm scale to promote agricultural development since 2010. A series of favorable polices has been adopted to support large-scale farming. Using a multivariate probit model and 2015 and 2016 rural household survey data, the present paper examines the factors that influence small farmers＂ decision to become large-scale farmers. The empirical regression results suggest that the decision to become a large-scale farmer is significantly influenced by household human capital cooperative membership, marketing channels, land-transfer contracts and government policies. However, the influence of these factors differs with respect to becoming large-scale grain and non-grain farmers. These results imply that policy tools should target these factors and the appropriate group of small-scale farmers. Generally, both central and local governments should promote large-scale farming by enhancing rural households＇ human capital improving marketing channels and providing agricultural social services, as well as encouraging returning migrant workers to engage in large-scale farming,展开更多
Large-scale farming by agricultural land transfers has been increasingly promoted in recent years,but the possible impacts on crop production,especially cash crops,and soil acidification remain unclear.This study obta...Large-scale farming by agricultural land transfers has been increasingly promoted in recent years,but the possible impacts on crop production,especially cash crops,and soil acidification remain unclear.This study obtained data for 110 banana plantations in Long’an County,China,and categorized them into small(<0.67 ha),medium(0.67−6.7 ha),and large(>6.7 ha)to determine banana cultivation,nutrient management,and soil acidification rates on farms of the three sizes.Banana yield per unit area significantly increased with increased farm size,and large farms had the highest average yield(48.9 t·ha^(−1))with the least variation.Despite a significant increase in organic fertilizer and base cation inputs,nitrogen(N)surplus did not differ significantly with increasing farm size.With large farms,actual soil acidification rate was significantly lower by 19.1 to 24.0 keq·ha^(−1)·yr^(−1);however,potential soil acidification rate increased with increased overuse of phosphorus.Overall,larger banana plantations used fewer mineral N fertilizers reducing the rate of soil acidification and increasing the H+buffering provided by organic fertilizers.It is concluded that larger farms deliver the dual benefits of higher,less variable banana yield and mitigation of soil acidification by substituting organic N for mineral N fertilizers,supporting sustainable soil management and food production.展开更多
The present study compared the prediction accuracy of the three CFD software packages for simulating airflow around a three-dimensional, isolated hill with a steep slope: 1) WindSim (turbulence model: RNG k-ε RANS), ...The present study compared the prediction accuracy of the three CFD software packages for simulating airflow around a three-dimensional, isolated hill with a steep slope: 1) WindSim (turbulence model: RNG k-ε RANS), 2) Meteodyn WT (turbulence model: k-L RANS), which are the leading commercially available CFD software packages in the wind power industry and 3) RIAM-COMPACT (turbulence model: standard Smagorinsky LES), which has been developed by the lead author of the present paper. Distinct differences in the airflow patterns were identified in the vicinity of the isolated hill (especially downstream of the hill) between the RANS results and the LES results. No reverse flow region (vortex region) characterized by negative wind velocities was identified downstream of the isolated hill in the result from the simulation with WindSim (RNG k-ε RANS) and Meteodyn WT (k-L RANS). In the case of the simulation with RIAM-COMPACT natural terrain version (standard Smagorinsky LES), a reverse flow region (vortex region) characterized by negative wind velocities clearly forms. Next, an example of wind risk (terrain-induced turbulence) diagnostics was presented for a large-scale wind farm in China. The vertical profiles of the streamwise (x) wind velocity do not follow the so-called power law wind profile;a large velocity deficit can be seen between the hub center and the lower end of the swept area in the case of the LES calculation (RIAM-COMPACT).展开更多
基金Supported by the Fund Program of Jiangsu Academy of Agricultural Sciences(6111689)the Planning Program of"the Twelfth Five-year-plan"in National Science and Technology for the Rural Developme+nt in China(2015BAD12B04-1.2)the Fund for Independent Innovation of Agricultural Science and Technology of Jiangsu Province[CX(16)1006]~~
文摘The application model of epidemic disease assessment technology for Web-based large-scale pig farm was expounded from the identification of epidemic disease risk factors, construction of risk assessment model and development of risk assessment system. The assessed pig farm uploaded the epidemic disease risk data information through on-line answering evaluating questionnaire to get the immediate evaluation report. The model could enhance the risk communication between pig farm veterinarian, manager and veterinary experts to help farm system understand and find disease risk factors, assess and report the potential high risk items of the pig farm in the three systems of engineering epidemic disease prevention technology, biological safety and immune monitoring, and promote the improvement and perfection of epidemic disease prevention and control measures.
文摘Large-scale breeding of livestock and poultry is the main way of modern animal husbandry development.This breeding method is widely used by the majority of owners because of its easy technical promotion,low breeding cost and good economic benefits.But with the development of large-scale livestock and poultry breeding,the pollution and damage to the environment caused by fecal pollution from large-scale livestock and poultry breeding has been criticized by many environmentalists.In this paper,through visit and investigation of large-scale livestock and poultry farms,the methods and measures of environmental protection in the construction of large-scale livestock and poultry farms are proposed.
基金Supported by Natural Science Foundation of Shandong Province(ZR2013CQ006)
文摘[Objective]The paper was to analyze the pathogenesis of Escherichia coli O123 from rex rabbit. [Method]E. coli O123 isolated from rabbit liver with diarrhea symptom in scale rex rabbit farm was intraperitoneally injected into 18- 22 g Kunming mice,and its pathogenicity was determined by clinical symptoms and pathological examination. [Result]When the inoculation concentration was about 8. 5 × 107 CFU /mL,Kunming mice appeared the clinical symptoms of drooping spirit,diarrhea and gathering,and the mortality reached 50%. Anatomical examination found that intestinal wall was thinning and intestinal mucosa was bleeding. [Conclusion]E. coli from rex rabbit has strong pathogenicity,and establishing animal model with Kunming mice to study its pathogenesis is of great reference significance for diagnosis and prevention of E. coli disease of rex rabbit.
文摘The Chinese Government has increased its focus on expanding farm scale to promote agricultural development since 2010. A series of favorable polices has been adopted to support large-scale farming. Using a multivariate probit model and 2015 and 2016 rural household survey data, the present paper examines the factors that influence small farmers＂ decision to become large-scale farmers. The empirical regression results suggest that the decision to become a large-scale farmer is significantly influenced by household human capital cooperative membership, marketing channels, land-transfer contracts and government policies. However, the influence of these factors differs with respect to becoming large-scale grain and non-grain farmers. These results imply that policy tools should target these factors and the appropriate group of small-scale farmers. Generally, both central and local governments should promote large-scale farming by enhancing rural households＇ human capital improving marketing channels and providing agricultural social services, as well as encouraging returning migrant workers to engage in large-scale farming,
基金funded by Major Science and Technology Project of Yunnan Province(202102AE090053-2)National Natural Science Youth Foundation of China(41907142)Natural Science Foundation of Hainan Province(422MS095)。
文摘Large-scale farming by agricultural land transfers has been increasingly promoted in recent years,but the possible impacts on crop production,especially cash crops,and soil acidification remain unclear.This study obtained data for 110 banana plantations in Long’an County,China,and categorized them into small(<0.67 ha),medium(0.67−6.7 ha),and large(>6.7 ha)to determine banana cultivation,nutrient management,and soil acidification rates on farms of the three sizes.Banana yield per unit area significantly increased with increased farm size,and large farms had the highest average yield(48.9 t·ha^(−1))with the least variation.Despite a significant increase in organic fertilizer and base cation inputs,nitrogen(N)surplus did not differ significantly with increasing farm size.With large farms,actual soil acidification rate was significantly lower by 19.1 to 24.0 keq·ha^(−1)·yr^(−1);however,potential soil acidification rate increased with increased overuse of phosphorus.Overall,larger banana plantations used fewer mineral N fertilizers reducing the rate of soil acidification and increasing the H+buffering provided by organic fertilizers.It is concluded that larger farms deliver the dual benefits of higher,less variable banana yield and mitigation of soil acidification by substituting organic N for mineral N fertilizers,supporting sustainable soil management and food production.
文摘The present study compared the prediction accuracy of the three CFD software packages for simulating airflow around a three-dimensional, isolated hill with a steep slope: 1) WindSim (turbulence model: RNG k-ε RANS), 2) Meteodyn WT (turbulence model: k-L RANS), which are the leading commercially available CFD software packages in the wind power industry and 3) RIAM-COMPACT (turbulence model: standard Smagorinsky LES), which has been developed by the lead author of the present paper. Distinct differences in the airflow patterns were identified in the vicinity of the isolated hill (especially downstream of the hill) between the RANS results and the LES results. No reverse flow region (vortex region) characterized by negative wind velocities was identified downstream of the isolated hill in the result from the simulation with WindSim (RNG k-ε RANS) and Meteodyn WT (k-L RANS). In the case of the simulation with RIAM-COMPACT natural terrain version (standard Smagorinsky LES), a reverse flow region (vortex region) characterized by negative wind velocities clearly forms. Next, an example of wind risk (terrain-induced turbulence) diagnostics was presented for a large-scale wind farm in China. The vertical profiles of the streamwise (x) wind velocity do not follow the so-called power law wind profile;a large velocity deficit can be seen between the hub center and the lower end of the swept area in the case of the LES calculation (RIAM-COMPACT).
