油菜精量联合直播机覆秸装置设计与试验

在长江中下游稻油轮作区，前茬水稻机收后秸秆全量留田，当接茬进行油菜精量联合直播作业时，浮秸易缠绕直播机触土部件，造成机具堵塞、种子落在秸秆上难以出苗等问题。为此，结合油菜覆草种植农艺措施，提出适于油菜直播水稻秸秆覆盖还田的机械化作业方案，设计了一种与油菜精量联合直播机配套的覆秸装置。通过理论分析，确定了覆秸装置关键环节工作部件的结构参数、安装位置与安装角及工作转速范围。控制秸秆喂入量分别为0.9、1.1、1.3kg/s，进行性能测试试验，验证了理论分析确定的各部件工作转速的适宜性和秸秆输送顺畅稳定性，结果表明，当播种覆秸作业机组配套69.9kW拖拉机、前进速度0.7m/s、捡拾装置滚筒转速80r/min、集秸装置螺旋输送器转速270r/min和链式提升装置转速270r/min时，机具作业顺畅，秸秆捡拾率达到90%以上。控制均匀铺放装置转速分别为210、240、270、300、330r/min，当转速为300r/min时，秸秆覆盖均匀率最高，超过92%。田间试验表明，覆秸直播机秸秆通过性能良好，各环节工作部件作业稳定，各项设计指标均满足技术标准要求，设计的覆秸装置与油菜精量联合直播机集成，一次作业可完成水稻浮秸的捡拾、堆集、输送、覆盖以及旋耕整地、开畦沟、施肥、油菜播种等工序，适宜在水稻机收后秸秆未作任何处理的稻茬田作业。

Design and Test of Straw Gather-Mulch Device of Combined Precision Rapeseed Seeder

In the middle and lower reaches of the Yangtze River, the rice and rapeseed are the most important crops. They are planted in turn, and after the rice is harvested, rapeseed will be planted in time. High-efficiency combined precision seeder is often used to plant the rapeseed, which could complete seedbed preparation, ditching, fertilizing and sowing at once. However, here is a difficulty left by the previous rice harvest that is the harvest machine threshes the grain and leaves the rice straw in the field. The straw is easy to entangle the soil-touching parts of the combined precision seeder to block the machine, as well as the seeds are easy to fall on the straw, and difficult to emerge. Considering the kind of agronomic practice of straws covering for rapeseed cultivation, an innovation mechanized operation scheme both suitable for rapeseed seeding and returning rice straw mulch to the seedbed was proposed. A straw gather-mulch device matching with combined precision rapeseed seeder was designed. Through theoretical analysis, the structural parameters, installation position and angle, and working speed range of the key components of the straw mulching device were determined. Carrying the performance tests, controlling the straw feed rate of 0.9kg/s, 1.1kg/s and 1.3kg/s respectively, the feasibility of the working speed of each component was determined by theoretical analysis and the stability of straw transportation were verified. The experiment showed when the seeding straw mulching operation unit was equipped with a tractor of 69.9kW, at the operation speed of 0.7m/s, the roller speed of the pickup device was 80r/min, the speed of auger and chain lifting device of straw collecting device was 270r/min, the planter and components worked steadily, and the straw picking rate could reach 90%. Controlling the speed of the uniform placement device to be 210r/min, 240r/min, 270r/min, 300r/min and 330r/min, the experiment showed when the rotational speed was 300r/min, the uniformity rate of straw covering was over 92%. The field experiment showed that the straw had gathered clearly and mulched appropriately, the working parts of each link were stable, and the design indexes all met the technical requirements. The research showed that the designed straw gather-mulch device was integrated with the combined precision rapeseed seeder, which could complete the rice straw picking, stacking, transporting, rotating tillage, furrow opening, fertilizing, rapeseed seeding and mulching of rice straw in one operation, and it was suitable for the operation of rice stubble field without any treatment of straw after harvest.