A projection pursuit model is presented in this paper for comprehensive evaluation of benefits of small watershed control.By using the model,small watershed control samples with many benefit evaluation indexes can be ...A projection pursuit model is presented in this paper for comprehensive evaluation of benefits of small watershed control.By using the model,small watershed control samples with many benefit evaluation indexes can be synthesized projective values with one dimension.The samples can be naturally evaluated according to the projective values.The parameters of the model is optimized by using real coding beased accelerating genetic aglrothm,which overcomes the shortcomings of large computation amount and difficulty of computer programming in traditional projection prusuit methods,and provides a new way for wide applications of projection pursuit technique to different evaluation problems in agricultural systems engineering.展开更多
[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the t...[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC （organic chemical pesticide） and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times： the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield （177 262.5 kg/hm2 ） and the income after deducting spraying cost （48 858.5 yuan/hm2 ） were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.展开更多
基金Foundation Item:Chinese N ational Natural Science Fund and Yantze Water Resouces Comm ission U nion Project(N o.5 0 0 996 2 0 ) Chinese National N atural Science Fund Project(No.4 98710 18)
文摘A projection pursuit model is presented in this paper for comprehensive evaluation of benefits of small watershed control.By using the model,small watershed control samples with many benefit evaluation indexes can be synthesized projective values with one dimension.The samples can be naturally evaluated according to the projective values.The parameters of the model is optimized by using real coding beased accelerating genetic aglrothm,which overcomes the shortcomings of large computation amount and difficulty of computer programming in traditional projection prusuit methods,and provides a new way for wide applications of projection pursuit technique to different evaluation problems in agricultural systems engineering.
基金Supported by Science and Technology Research and Development Program of Chengde City in 2011(201121167)
文摘[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC （organic chemical pesticide） and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times： the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield （177 262.5 kg/hm2 ） and the income after deducting spraying cost （48 858.5 yuan/hm2 ） were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.
