小麦复式播种机种床构建装置设计与试验

Design and Experiment of Seedbed Construction Device for Wheat Compound Seeder

摘要:

针对长江中下游地区小麦播种普遍存在种床条件不理想和畦沟质量不高等问题，设计了一种种床构建装置，提出了一种旋耕+开沟+播前镇压+护沟的设计方案。该装置主要由旋耕部件、铧式犁开沟部件和播前镇压部件等组成，能够一次作业完成旋耕、开沟、播前镇压、播种施肥等工序，采用镇压强度可调节的播前镇压和横向输土技术，有效构建地表平整、虚实结合的理想种床。根据小麦种植农艺要求，确定了旋耕刀的数量以及排列分布，设计了铧式犁开沟器和播前镇压部件的关键参数；通过EDEM软件建立仿真模型，通过二因素四水平正交试验和Box-Behnken试验方法分别对铧式犁开沟器和种床构建装置进行仿真分析，得到铧式犁开沟器终止滑切角和护沟侧板水平方向最优倾角分别为68°和67°，得到优化工作参数为：机具前进速度4.22km/h、旋耕刀转速288r/min和液压缸伸长量85.50mm。在土壤含水率22.3%、土壤容重1.11g/cm3的田间进行试验，结果表明，作业后碎土率为92.75%，种床平整度为15.32mm，土壤容重为1.34g/cm3，畦沟平均深度为201mm，畦沟沟深稳定性系数达到91.38%，小麦出苗均匀整齐，出苗率为89.24%，满足小麦高质量播种要求。

Abstract:

The low seedbed quality and the poor furrow construction was a major problem constraining wheat production in the lower reaches of the Yangtze River region. To address this problem, a technical process featured with “rotary tilling + furrow opening + pre-seeding compaction + furrow stabilizing” was proposed and a key functional component was designed. The key part of the seeder was its assemblage of a rotor tiller, a set of moldboard plough furrow opener, and a pre-seeding compacting roller. This design facilitated one-pass seeding operation which included rotary tilling, furrow opening, pre-seeding compaction, and starter fertilizing etc. The combined usage of both the pressure-adjustable pre-seeding compacting roller and the trans-directional soil transporting technology guaranteed a levelled and well loose-compact mediated seedbed for optimal wheat germination. With respect to the agronomic specifications for wheat cultivation, suitable number of the rotary knives and their arrangement on the rotor was determined and the key parameters of both the moldboard plough furrow opener and the pre-seeding compacting roller were optimized. EDEM simulating program was used for 2-factor and 4-level orthogonal experiment and the simulated results were analyzed and plotted with Box-Behnken method, from which the terminal angle (i.e. 68°) of the moldboard plough furrow opener and the optimal horizontal tilting angle (i.e.67°) for the side plate of the furrow stabilizer were determined. The whole-system optimization of the one-pass seeder included a forwarding speed of 4.22km/h, a rotational speed of 288r/min for the rotary tiller and a 85.50mm workable range for the hydraulic cylinder. The experiment was carried out in the field with soil moisture content of 22.3% and soil bulk density of 1.11g/cm3, the results showed that post-seeding soil fragmentation was 92.75%, soil micro-relief was 15.32mm, soil volumetric weight was 1.34g/cm3, mean furrow depth was 201mm and the furrow depth uniformity was 91.38%. Wheat seedling emergence was uniform, with a germination rate of 89.24%, meeting the agronomic requirement for wheat cultivation.