基于直插破膜成穴特性的玉米全膜双垄沟机械化播种方式作业机理及其产量效应研究

The furrow sowing with whole plastic-film mulching on double ridges has been widely used in the arid region of northwest China, because it can resist drought and increase production. So the mechanical sowing on film is an inevitable trend in farming. Under the theory of granular dynamics and soil dynamics and the technology of DEM, non-linear finite element method and high-speed photography, this project studies about direct insert precision hill-seeder with corn whole plastic-film mulching on double ridges. In order to reveal operation mechanism and effect mechanism with sowing methods of properties about direct insert and puncture film and cavitation under different parameters of corn whole plastic-film mulching on double ridges, the micromechanics constitutive models of different periods and different cycle film mulching seedbed is constructed, and probes the interrelationship between hill-seeder equipment and film mulching seedbed. Based on changes properties in the membrane and soils of film mulching seedbed, the project combines experiment and relationship models, to analyse the yield index under different parameters of the sowing methods properties of direct insert and puncture film and cavitation, and study the internal mechanism of sowing methods and its yield effect, which expounds the theory of yield increase of the properties sowing methods with whole plastic-film mulching on double ridges. Accordingly, it proposes appropriate planting models of the mechanical sowing methods of corn whole plastic-film mulching on double ridges in the arid region of northwest China. The results will undoubtedly provide theoretical basis for the integration of agricultural machinery equipments and the technology of corn furrow sowing with whole plastic-film mulching on double ridges, and effectively promote the development of the mechanical sowing on film technology of corn whole plastic-film mulching on double ridges in China.

全膜双垄沟播技术抗旱、增产被我国西北旱农区大面积推广，机械化膜上播种是必然趋势。项目依托具有自主知识产权的玉米全膜双垄沟直插式精量穴播机，结合散体动力学和土壤动力学理论，利用离散元法、非线性有限元法及高速摄像技术，通过构建玉米全膜双垄沟不同时期、周期覆膜种床细观本构模型，研究播种条件下成穴装置与覆膜种床的相互作用关系，明确该类播种方式不同参数对其膜上作业性能的影响机制，揭示直插破膜成穴特性播种方式的作业机理。基于覆膜种床膜土特性变化，采用试验和关系模型建立相结合的方法，通过不同参数播种方式下各产量指标测定分析，研究播种方式与其产量效应的内在关联机制，阐明基于直插破膜成穴特性播种方式作用下的全膜双垄沟增产效应原理。据此，提出我国西北典型旱区玉米全膜双垄沟适宜的机械化膜上播种模式。研究成果将为农机装备与玉米全膜双垄沟播农艺技术相融合提供理论依据，有效推动我国玉米全膜双垄沟膜上播种技术的发展。

全膜双垄沟播技术抗旱、增产被我国西北旱农区大面积推广，实现机械化膜上播种是必然趋势。项目通过对玉米全膜双垄沟不同时期-周期覆膜种床物理机械特性进行研究，获得不同类型机械化覆膜种床在玉米生育期内垄沟土壤温度、土壤含水率、地膜力学特性及种床各部分土壤紧实度等物理特性参数。借助离散元理论，在结合覆膜种床物理特性参数的基础上对全膜双垄沟覆膜种床细观本构模型进行建立，基于EDEM方法数值模拟直插式玉米膜上播种作业过程，研究该播种条件下直插式成穴装置与覆膜种床的相互作用关系，明确了影响直插式播种作业方式的关键工作参数，揭示了“直插、破膜、成穴”特性播种方式的作业机理；同时以此机理为指导，对近等速补偿机构、强排播种机构、前进速度补偿机构和直插限深机构进行了仿真设计与理论分析，分别研制了基于近等速机构的玉米全膜双垄沟穴播机和电驱式玉米膜上直插穴播机，并进行了田间试验。结合响应曲面法、Box-Behnken试验设计，分别建立了基于近等速机构的玉米全膜双垄沟穴播机相关曲柄转速、机器前进速度、主动杆转速对穴孔错位率、采光面地膜机械破损率影响的二次回归模型和电驱式玉米膜上直插穴播机相关主曲柄角速度、中心距、副曲柄长度对膜下播种深度合格率和膜孔合格率影响的二次回归模型，借助Design-expert软件优化工具箱实现对两类样机关键结构参数、运动参数的优化与作业性能提升。应用研发的基于近等速机构的玉米全膜双垄沟穴播机、电驱式玉米膜上直插穴播机以及传统轮式穴播机进行玉米全膜双垄沟播种作业性能对比试验，针对播种后田间玉米出苗与长势情况，阐明基于直插破膜成穴特性播种方式作用下的全膜双垄沟增产效应原理。据此，提出我国西北典型旱区玉米全膜双垄沟适宜的机械化膜上播种模式。本项目研究成果丰富了全膜双垄沟膜上直插式播种理论与方法的内涵，将为西北旱区农机装备与玉米全膜双垄沟播农艺技术相融合提供理论依据，有效推动我国玉米全膜双垄沟膜上播种技术的发展。