Authors

Abstract

To address the limited maneuverability and terrain adaptability of conventional liquid-fertilizer injection equipment in hilly and small-plot farmland, a compact self-propelled injector integrating a narrow-track four-wheel-drive chassis, an angle-adjustable injection unit, and a crank-slider penetration mechanism was developed. Unlike large tractor-mounted or fixed-orientation systems, the proposed machine integrates inter-row movement, posture adjustment, needle penetration, and timed point injection on a lightweight platform. The discharge characteristics of the injection needle were investigated using computational fluid dynamics, and a three-factor, three-level Box–Behnken design was employed to optimize injection duration, inlet pressure, and outlet-hole number, with fertilizer volume per injection as the response. Response surface optimization identified an injection duration of 1 s, an inlet pressure of 0.45 MPa, and six outlet holes as the preferred parameter combination. Field validation yielded a measured fertilizer volume of 675.4 mL per injection, compared with the predicted value of 700 mL, corresponding to a relative difference of 3.51%. The results demonstrate the feasibility of controllable deep point placement under the tested conditions and provide a lightweight equipment solution for liquid-fertilizer application in hilly and small-plot farmland.

Abstract in Chinese

针对传统液肥注射施肥装备在丘陵山区及小地块农田中机动性和地形适应性不足的问题，研制了一种集窄距四轮驱动底盘、角度可调式注射单元和曲柄滑块入土机构于一体的小型自走式液肥注射机。与大型拖拉机悬挂式或固定姿态作业系统相比，该机可在轻量化平台上实现行间行走、姿态调节、施肥针入土及定时定点注肥。采用计算流体动力学方法分析施肥针排液特性，并以单次注肥体积为响应值，开展三因素三水平Box–Behnken响应面试验，对注肥时间、入口压力和出液孔数进行优化。响应面优化得到较优参数组合为注肥时间1 s、入口压力0.45 MPa和出液孔数6个。田间验证中，单次注肥体积实测值为675.4 mL，模型预测值为700 mL，相对误差为3.51%。结果表明，所研制机具在试验条件下能够实现可控的液肥定点深施，可为丘陵山区及小地块农田液肥机械化施用提供轻量化装备方案。