Study On Precision Seeding And Soil Supplying Device For Simplified Tray Nursing Seedlings Assembly Line Of Rice

Rice is one of the major food crops in China.The planting area of rice accounts for about 30% of the country's total grain planting area,and the hybrid rice planting area accounts for more than 50%.Hybrid rice mainly relies on strong tillering ability to obtain high yield,emphasizing less rare planting.Currently,the main cultivation methods are seedling raising and artificial transplanting.As the main equipment for rice nursing seeding,the existing seeding device is mostly used for conventional rice sowing.The seeding device for hybrid rice sowing has a complex structure and less application.At the same time,the existing soil supplying device cannot be adjusted,affecting the result of soil supply.Therefore,in order to adapt to the requirements of simplify cultivation.There is an urgent need to develop a kind of precision seeding device with simple structure and satisfying the low-seeding requirements of hybrid rice,and a kind of height-adjustable soil supplying device that can automatically control the delivery volume of soil.This paper analyzes and summarizes the current research status of seeding and soil supplying devices used in assembly line for tray nursing seedlings of rice at home and abroad.Combining the low-seeding technical requirements of hybrid rice and soil supply requirements,researching the key techniques for precision seeding and soil supply in assembly line for tray nursing seedlings of rice.Using a combination of theoretical analysis,simulation and experimental research,a seeding device and a soil supplying device for simplified tray nursing seedlings assembly line of rice were developed.The main research contents and conclusions are as follows:(1)Precision seeding device for simplified tray nursing seedlings assembly line of rice adopts a vibration chamber,multi-layer skateboard structure and a socket seeding wheel.Seeds form a uniform seed stream in the vibration chamber.After the seed enters the filling area,it is broadcasted by the socket seeding wheel.It is not only suitable for precisionIV seeding of hybrid rice,but also suitable for conventional rice seedlings.(2)Using EDEM software to simulate the seeding process,analysis the seed's filling situation and movement during the seeding process,and obtain the main structural parameters of the socket seeding wheel for filling and ensuring the uniformity.The Inventor software was used to establish the 3D model of the seeding device.Import the model into EDEM software and simulate to obtain a graph showing the speed,force,and displacement of seed particles as a function of time during sowing.Combined with simulation animation,the theoretical analysis of the process of filling,clearing,protecting and seeding was carried out.The EDEM software post-processing module was used to count the number of seeds in the socket of the protecting area,and analysis the effect of the depth(h)of the socket and the diameter(d)of the socket on the seed-filling performance.The results showed that the effect of the depth(h)of the socket on the filling volume and uniformity of the seeding wheel was greater than the diameter(d)of the socket.With the increase of the diameter(d)of the socket and the depth(h)of the socket,the number of seeds in the single socket increased.(3)Through experiments,the optimal parameter of the seeding wheel of the simplified tray nursing seedlings assembly line of rice was determined.The results showed that the qualified rate of hybrid rice was 86.2% and the sowing empty rate was 2.2%;the qualified rate of conventional rice sowing was 88.6% and the sowing empty rate was 0.Using “Peizataifeng” hybrid rice seeds,three factors and three levels of orthogonal test were designed to investigate the effect of the depth(h)of the socket,the diameter(d)of the socket,and the axial distance(s)between the socket on the seeding performance of the socket seeding wheel.The results show that the primary and secondary factors affecting the seedling qualified rate are: the depth(h)of the socket> the diameter(d)of the socket> the axial distance(s)between the socket;the order of the factors influencing the sowing empty ratio is: the axial distance(s)between the socket> the diameter(d)of the socket> the depth(h)of the socket.The best parameters for the seeding qualified rate and seeding empty rate of hybrid rice were h=4mm,d=13mm,and s=17mm.At this time,the sowing qualified rate was 86.2%,and the sowing empty rate was 2.2%,which satisfied the technical requirements for low-seeding precision sowing of hybrid rice.Use the “Huahang31”conventional seed to test,the qualified rate was 88.6%,and the sowing empty rate was 0.This indicates that precision seeding device for simplified tray nursing seedlings assembly line of rice is also suitable for conventional rice seeding.(4)Soil supplying device for simplified tray nursing seedlings assembly line of rice consists of belt conveyor components,height adjustment mechanism and soil quantity detection and control system.Ultrasonic sensor is used to judge the distance and the Arduino single chip microcomputer is used as the core control chip.The soil quantity detection and control system of the soil supplying device is designed to realize the function of automatically controlling the start and stop according to the amount of soil when the soil supplying device works.(5)The adaptability of the soil supplying device to different soil and assembly line for tray nursing seedlings of rice was verified through tests.The tests showed that the transport capacity and control system meet the requirements for the use of existing tray nursing seedlings assembly line of rice.Taking the type of nursery soil and the height of elevation as variables,a two-factor and three-level full factorial experiment was conducted to study the ability of the soil supplying device to transport nursery soils with different properties and the adaptability to different heights of assembly line for tray nursing seedlings of rice.The test results show that the conveying capacity of the soil supplying device to different kinds of nursery soil is in the following order: the mixture of the nursery soil and the substrate> the nursery substrate> the nursery soil,the conveying capacity and the control system meets the requirements for the use of the existing assembly line for tray nursing seedlings of rice.