<i>No-tillage tine furrow opener performance: soil-tool-residue interactions, tool geometry and settings</i>

Abstract

Abstract. The aim of no-tillage farming is to minimize mechanical soil disruption for soil and water (irrigation, rainfall) conservation, which includes adequate year-round crop residue cover. Furrow opening in this mechanization system is therefore of great importance being the only soil loosening operation performed to create optimum seed zone conditions for germination and subsequent crop establishment. The goals of no-tillage furrow opener design are minimal soil disturbance, and low draft and vertical force requirements. The design should also be able to support other components of the seeding system so as to retain adequate on-row residue cover, ensure accurate and uniform depth of seed placement, and plant spacing. This review highlights how these goals are affected by opener type and geometry, opener and seeder settings, and operating conditions. Conventional tine openers cause greater soil disturbance than narrow tine openers. Winged openers reduce residue interference with seed placement, and cause subsurface soil shattering, which helps conserve soil moisture. An increase in rake angle, tine width, and operating depth leads to increased soil disturbance and draft. Concave cutting edge allows for reduced soil disturbance and satisfactory clearance of crop residue. Increasing forward speed reduces residue interference with sowing and decreases seeding depth. Soils with high clay content (e.g., >35%) are likely to have lower soil disturbance. Bentleg openers cause less soil disturbance at high speeds, up to 16 km/h with lower draft force requirement and 100% seed coverage. Further research is needed on tine openers with concave cutting edge to establish and improve their ability to reduce soil disturbance and facilitate residue removal. There is a need for bentleg furrow openers to be evaluated in cohesive and adhesive soils to assist design optimization for such soils.