Substantiation of ridge formation during inter-row tillage of soybean crops by a robotic tiller

Abstract

The influence of design parameters and working tools on the formation of a ridge of varying height depending on the soybean development stage during inter-row tillage is discussed. The tillage was performed on soybean crops with a row spacing of 45 cm using a Helios Agrokraft robotic tiler equipped with the EXACT automatic precision guidance system and working tools in the form of two one-sided shares and one sweep share located in the center of the row. Two inter-row tillage operations were performed during the growing season at operating speeds of 10–12 km h. The first tillage was carried out at the first to second trifoliate leaf stage using protective discs, and the second - from the third trifoliate leaf stage to row closure without protective discs. It was found that the first tillage formed a ridge with a height of 3.08 ± 0.01 cm, while the second one formed a ridge of 7.08 ± 0.04 cm. A mathematical model in the form of a third-order polynomial was proposed. A comparison of the two obtained dependences showed that all the equation coefficients for the second inter-row tillage were larger in absolute value than those for the first one which was experimentally confirmed by the height of the formed ridge. Symmetry in ridge formation for adjacent rows was revealed, the difference being 0.02–0.09 cm which was within the absolute measurement error. The two-stage technology allows, in the early stages, due to the protective discs, to avoid covering the plants and ensure soil warming, and at later stages - to improve root zone aeration, enhance weed suppression, and drain excess moisture. No damage to crop plants by the working tools was found. The obtained results confirm that ridge formation is a fully valid agronomic practice, and the use of a robotic tiller with a precision guidance system ensures accurate operation at speeds of 10–12 km h.