Soil translocation by narrow openers with various blade face geometries

Abstract

Australian no-till farming often uses narrow point openers to open the soil and place seed and fertiliser into the furrow. They are generally used in conjunction with the spraying of pre-emergence herbicides for weed control and press-wheels to pack soil over the seeds. These openers can create excessive soil throw which creates problems such as increasing depth of soil cover on adjacent furrows, herbicide contamination above seeds in adjacent furrows, increased stimulation of weed seed germination and soil moisture loss. This study evaluated the effect of blade face geometry of a vertical narrow opener on soil movement, comparing single side and double side chamfers with a blunt face. PVC cubic tracers embedded in the soil were used to quantify soil movement created by the openers operating at a 120 mm depth and 8.2 km h−1. The effect of a chamfer was seen to significantly decrease lateral and forward soil movement, and increase furrow size. A chamfer also reduced the amount of surface soil moved out of the furrow and reduced the amount of deeper soil brought up into the seed zone. These findings have implications for optimising no-till seeding practices such as seeding into marginal moisture as well as improving crop safety and in-furrow weed control when using pre-emergence herbicide incorporated by sowing.