Design and experiments of a drip tape trenching and shallow burial device based on self-braking

Drip irrigation has been one of the most efficient water-saving irrigation modes in arid and semi-arid regions, due to its water use efficiency and crop yields. Subsurface shallow burial installation can directly deliver water and fertilizers to crop root zones, thereby minimizing water evaporation loss from the surface soil dry and effectively suppressing the growth of pests, diseases, and weeds. Typically, trenching, belt laying, and soil covering are included in the subsurface shallow burial installation of drip tape. Among them, the trenching and shallow burial stage can dominate the burial depth accuracy and installation quality of the drip tape. However, it is often required for manual fixation at the free end of the drip tape during initial installation, particularly for the unstable trenching depth. Belt slack can also occur during emergency braking. In this study, a drip tape trenching and shallow burial device was designed with self-braking mechanism, including a contour-following trenching and shallow burial mechanism, a drip tape guidance mechanism, a drip tape clamping mechanism, a drip tape roller, a braking mechanism, and a tape press-down mechanism. Functions were integrated in the device, such as stable trenching, belt pressing, and self-braking. Specifically, contour-following trenching and shallow burial mechanism was used to precise control of the drip tape burial depth using a sliding blade-type furrow opener and a parallelogram profiling structure, i.e., a sliding blade-type furrow opener with a 45° sliding-cutting angle and a 45° blade edge angle, along with a parallelogram profiling mechanism in a profiling range of 93.78 mm. Tape press-down mechanism was used to effectively restrain the displacement of the free end of the drip tape using an elastic compaction wheel. Tension spring parameters were designed after optimization, according to the required tension range of 242.94-488.70 N. In braking mechanism, the coordination between a brake rod and a brake wheel was utilized to prevent slack in the drip tape during emergency braking. The tension range of the brake tension spring was calculated as 44.89-67.35 N using the drip tape's tensile force. A soil bin test was conducted to verify the performance of the device. The results showed that the average burial depth of the drip tape ranged from 37.4 to 48.1 mm at different operating velocities, with a burial depth stability exceeding 94%, fully meeting the agronomic standards. The displacement of the drip tape in the tape press-down mechanism was less than 1 000 mm at various velocities, particularly without manual fixation. The well-designed tension spring parameters enabled the friction rubber pad to engage rapidly with the brake wheel during emergency braking, thereby effectively suppressing inertial slack. A tension spring force of 55 N or higher achieved high braking performance at an operating velocity of 6 km/h. The post-braking slack of the drip irrigation belt was significantly reduced from 8 674.6 mm (without the braking mechanism) to 32.4 mm at the tension spring force of 60 N, indicating a reduction of over 99%. This findings can provide theoretical and technical support to promote the shallow burial installation of drip tapes during irrigation in sustainable agriculture.