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
文摘为明确18%噁唑酰草胺·噁嗪草酮乳油对直播水稻田一年生禾本科杂草的防除效果及其对水稻的安全性。参照GB/T 17980.40—2000《农药田间药效试验准则(一)》于2023年在水稻2.5~4叶期,禾本科杂草2~4叶期采用茎叶喷雾法开展大田试验。试验结果显示18%噁唑酰草胺·噁嗪草酮乳油有效成分用药量108.0~135.0 g a.i./hm^(2),可有效防除稗草、马唐、千金子等一年生禾本科杂草,药后30 d株和鲜重防效分别为89.07%~92.51%和92.00%~94.13%。18%噁唑酰草胺·噁嗪草酮乳油能够有效防除直播水稻田一年生禾本科杂草,且对水稻生长安全,杀草速度较快。
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.
