Development of a mechanical weeder and experiment on the growth,yield and quality of rice

Weed control in paddy fields is a worldwide problem and mechanical weeding will become a major weeding method in non-chemical weeding.A mechanical weeder was designed and tested to improve the efficiency of mechanical weeding and reduce the application of herbicides in this study.The weeding equipment is equipped with three sets of inter-row weeding parts which include ground-contoured-following pressing-grass float(GPF),weeding roller and so on.The weeding principle of weeding part is that the weeding equipment enters the inter-row area with weeder moving forward,then the GPF overwhelms the weeds in the inter-row area to improve the probability that the weeding roller behind the GPF pressed the overwhelmed weeds into the soil.The effects of weeding methods on the plant height,grain yield and quality attributes were investigated in a two-seasonal field experiment.Three weeding methods were applied in the present study:no-weeding,chemical weeding and mechanical weeding.The results of the two-seasonal field experiment showed that the average weeding rates of mechanical weeders were 87.1%and 87.61%respectively.In both seasons,there was no significant difference among weeding methods on plant height at the early growth stage of rice after weeding,but weeding methods had significant effect on plant height at the late growth stage.The plant height of mechanical weeding was higher at the late growth stage.Weeding methods had significant effects on grain yield,grain number per panicle,seed-setting rate,1000-grain weight and shoot dry matter accumulation(p<0.05),however there was no remarkable effect on rice quality and other attributes(p>0.05).Grain yield of mechanical weeding was significantly higher than that of no-weeding.There was no significant difference between chemical weeding and mechanical weeding.It can be concluded from the two-seasonal experiment that mechanical weeding had the same effect as chemical weeding on grain yield and rice quality.

Field experimental study on pullout forces of rice seedlings and barnyard grasses for mechanical weed control in paddy field

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.

Comparison of efficiencies and costs of different weed control methods in paddy production in Iran

Using of efficient and inexpensive method for weed control has an important role in increasing efficiency and reducing costs of production.In this study,field experiments were carried out to evaluate the efficiency and costs of several weed control methods in paddy production during summer in Mazandaran,the north province of Iran in 2011.Seven weed control treatments(T1 to T7)were applied at three stages of rice growth(20 and 35 days after transplanting and grain harvesting time).Weed density,weed dry weight,labor used and economical comparison were determined in the basis of a complete randomized block design with three replications.Results showed that there were no significant differences among efficiencies of six treatments(except for weedy check method(T6)treatment).The minimum weed density and dry weight were obtained at herbicide+hand weeding once(T5)and herbicide application once(T7)treatments during all three stages.The costs of weed control were different among the treatments.Selection of control method has an important role in reducing labor.Hand weeding twice method(T1),because of its high weeding cost,hard work and worker restriction in the required time,is not useful.Powered weeding twice method(T2),due to its zero environment pollution,reducing costs of weed control and high benefit/cost,is the best and most appropriate treatment.Amount of weed damage in weedy check method(T6)varied between 30.5%and 45.3%.

Review of non-chemical weed management for green agriculture

This paper reviewed the background and situation for studying and developing non-chemical weed management.Environmental pressure and commissariat safety problems indicate that it is essential to deeply study and develop non-chemical weed management technologies.The paper summarized the pros and cons of the non-chemical weed management technologies in aspects of weed control by agronomic method,mechanical method,thermal treatment method,and biological treatment,discussed the defects of the existing non-chemical weeding methods,and put forward some suggestions:(1)The description on the experiments and operation of the non-chemical weeding technologies is suggested to be standardized in order to compare the performance of different weeding methods.Some important information on name of equipment,consumption capacity,working width,travel speed,and weed control levels should always be included in the experimental descriptions;(2)An integration of combinations or sequences of various weed control techniques is suggested to be used to reduce the risk of a selective pressure leading to the predominance of certain species;and(3)It is also suggested for further improvement of the existing weed control methods and further development of the weed detection technology originally developed for precision chemical application in order to use them in non-chemical weed management.