In this study, the allelopathic effects of 100 g/L water extract of Melilotus offtcinalis Desr. on seed germination and seedling growth of Melilotus offwinalis Desr., Trifolium pretense L. , Medicago sativa L. cv. Vic...In this study, the allelopathic effects of 100 g/L water extract of Melilotus offtcinalis Desr. on seed germination and seedling growth of Melilotus offwinalis Desr., Trifolium pretense L. , Medicago sativa L. cv. Victoria, Echinochloa crusgalli （ L. ） Beauv., Lxer/s chinensis （ Thunb. ） Nakai and Plantago asiatica L. were investigated by biological assay. Dried powder of Melilotus officinalis Desr. was applied to the field in spring and winter to verify the inhibitory effects of Me- lilotus officinalis Desr. on weed biomass in the experimental field and compare the effects between Melilotus offwinalis Desr. and a variety of commonly used chemi- cal herbicides on weed suppression. The results showed that water extract of Melilotm officinalis Desr. posed significant effects on seed germination and seedling growth of Trifolium pretense L. , Echinochloa crusgalli （ L. ） Beauv. , Lxeris chinensis （ Thunb. ） Nakm, Plantago asiatica L. , Melilotus o^tcinalis Desr. and Medi- cago sativa L. cv. Victoria, exhibiting strong allelopathic effects, but the inhibition rate varied greatly among different plant species. Therefore, the allelopathic effects of Melilotus o^winalis Desr. should be utilized appropriately in practical applieatians. Dried powder of Melilotus officinalis Desr. significantly reduced weed quantity in the field for a short duration, which should be administered multiple times in a sufficient amount for weed control in the production.展开更多
Pullout forces of rice seedling and barnyard grass were tested by universal testing machine controlled by WDW-5 type microcomputer to obtain the pullout forces of rice seedling and barnyard grass.The measured pullout ...Pullout forces of rice seedling and barnyard grass were tested by universal testing machine controlled by WDW-5 type microcomputer to obtain the pullout forces of rice seedling and barnyard grass.The measured pullout force was used to improve the weeding rate and reduce the rice seedling damage rate caused by mechanical weeding device.According to the measured continuous curve of pullout forces of rice seeding and barnyard grasses in weeding period,the best range of force required to pull out barnyard grasses from soil with no injury and damage to rice seedlings was discussed.Reasons for the difference in the pulling force were analyzed.Results show that,with the increment of the number of single cell rice seedlings the pullout force increases.The pullout forces of single cell rice seedlings and barnyard grasses at first increased slowly reaching the maximum value followed by rapid drop and finally it remained steady.The minimum pullout forces recorded during rice seedlings at the first and the second weeding periods were 2.57 N and 9.70 N,respectively,while the minimum forces during the first and second weeding periods were recorded as 1.24 N and 7.51 N,respectively,for barnyard grasses.The results show that the pullout forces of weeding to rice seedlings and barnyard grasses should be within 1.24 N to 2.57 N and 7.51 N to 9.70 N respectively in the first and second weeding periods.展开更多
Target detection is one of research focuses for precision chemical application.This study developed a method to identify seedling cabbages and weeds using hyperspectral imaging.In processing the image data with ENVI s...Target detection is one of research focuses for precision chemical application.This study developed a method to identify seedling cabbages and weeds using hyperspectral imaging.In processing the image data with ENVI software,after dimension reduction,noise reduction,de-correlation for high-dimensional data,and selection of the region of interest,the SAM(Spectral Angle Mapping)model was built for automatic identification of cabbages and weeds.With the HSI(Hyper Spectral Imaging)Analyzer,the training pixels were used to calculate the average spectrum as the standard spectrum.The parameters of the SAM model,which had the best classification results with 3-point smoothing,zero-order derivative,and 6-degrees spectral angle,was determined to achieve the accurate identification of the background,weeds,and cabbages.In comparison,the SAM model can completely separate the plants from the soil background but not perfect for weeds to be separated from the cabbages.In conclusion,the SAM classification model with the HSI analyzer could completely distinguish weeds from background and cabbages.展开更多
基金Supported by Natural Science Foundation of China(31101764)Natural Science Fund for Colleges and Universities in Jiangsu Province(11KJB230004)
文摘In this study, the allelopathic effects of 100 g/L water extract of Melilotus offtcinalis Desr. on seed germination and seedling growth of Melilotus offwinalis Desr., Trifolium pretense L. , Medicago sativa L. cv. Victoria, Echinochloa crusgalli （ L. ） Beauv., Lxer/s chinensis （ Thunb. ） Nakai and Plantago asiatica L. were investigated by biological assay. Dried powder of Melilotus officinalis Desr. was applied to the field in spring and winter to verify the inhibitory effects of Me- lilotus officinalis Desr. on weed biomass in the experimental field and compare the effects between Melilotus offwinalis Desr. and a variety of commonly used chemi- cal herbicides on weed suppression. The results showed that water extract of Melilotm officinalis Desr. posed significant effects on seed germination and seedling growth of Trifolium pretense L. , Echinochloa crusgalli （ L. ） Beauv. , Lxeris chinensis （ Thunb. ） Nakm, Plantago asiatica L. , Melilotus o^tcinalis Desr. and Medi- cago sativa L. cv. Victoria, exhibiting strong allelopathic effects, but the inhibition rate varied greatly among different plant species. Therefore, the allelopathic effects of Melilotus o^winalis Desr. should be utilized appropriately in practical applieatians. Dried powder of Melilotus officinalis Desr. significantly reduced weed quantity in the field for a short duration, which should be administered multiple times in a sufficient amount for weed control in the production.
基金the financial support provided by Specialized Research Fund for the Doctoral Program of Higher Education(20102325110002,20112325110006)National Key Technology Support Program(2014BAD06B00)Heilongjiang Postdoctoral Fund(LBH-Z13030).
文摘Pullout forces of rice seedling and barnyard grass were tested by universal testing machine controlled by WDW-5 type microcomputer to obtain the pullout forces of rice seedling and barnyard grass.The measured pullout force was used to improve the weeding rate and reduce the rice seedling damage rate caused by mechanical weeding device.According to the measured continuous curve of pullout forces of rice seeding and barnyard grasses in weeding period,the best range of force required to pull out barnyard grasses from soil with no injury and damage to rice seedlings was discussed.Reasons for the difference in the pulling force were analyzed.Results show that,with the increment of the number of single cell rice seedlings the pullout force increases.The pullout forces of single cell rice seedlings and barnyard grasses at first increased slowly reaching the maximum value followed by rapid drop and finally it remained steady.The minimum pullout forces recorded during rice seedlings at the first and the second weeding periods were 2.57 N and 9.70 N,respectively,while the minimum forces during the first and second weeding periods were recorded as 1.24 N and 7.51 N,respectively,for barnyard grasses.The results show that the pullout forces of weeding to rice seedlings and barnyard grasses should be within 1.24 N to 2.57 N and 7.51 N to 9.70 N respectively in the first and second weeding periods.
基金This research was financially supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA101904)the National High Technology Research and Development Program of China(984 Program)(2011-G32).
文摘Target detection is one of research focuses for precision chemical application.This study developed a method to identify seedling cabbages and weeds using hyperspectral imaging.In processing the image data with ENVI software,after dimension reduction,noise reduction,de-correlation for high-dimensional data,and selection of the region of interest,the SAM(Spectral Angle Mapping)model was built for automatic identification of cabbages and weeds.With the HSI(Hyper Spectral Imaging)Analyzer,the training pixels were used to calculate the average spectrum as the standard spectrum.The parameters of the SAM model,which had the best classification results with 3-point smoothing,zero-order derivative,and 6-degrees spectral angle,was determined to achieve the accurate identification of the background,weeds,and cabbages.In comparison,the SAM model can completely separate the plants from the soil background but not perfect for weeds to be separated from the cabbages.In conclusion,the SAM classification model with the HSI analyzer could completely distinguish weeds from background and cabbages.
