Descripción
Australian no-till farming often uses narrow point
openers to open the soil and place seed and fertilizer in a furrow. They are
generally used in conjunction with spraying of herbicides for weed control and
press-wheels to pack soil over seeds. These openers when operating at speeds
beyond 8 km/h can create excessive soil throw which creates problems of
increased weed burden and reduced seeding quality, which can also enhance crop
establishment risks due to herbicide damage and soil moisture loss. This work
uses the results of surface PVC tracer displacement to estimate the likely
movement of soil applied pre-emergent herbicide, typically incorporated during
the no-till seeding operation, and evaluate the effects of furrow opener
geometry. Three variations to opener design were evaluated; four rake angles of
35, 53, 72 and 90°, three leading edge conditions of blunt, chamfered one side
and chamfered both sides, and a range of fi ve bent leg openers. The effect of
the various narrow opener geometries on soil movement and furrow profi le were
evaluated in a soil bin with a sandy loam soil and at a forward speed of 8.2
km/h and a depth of 120 mm. Results showed that the openers with various rake
angles all threw surface soil at least 300 mm from the center and this would
land in an adjacent furrow when used at typical row spacings. A low rake angle
of 35° had the least lateral surface soil movement and the 53° rake angle gave
the widest band of soil, along the tool path, that was cleared of surface
tracers. Adding a chamfer to the leading edge reduced lateral soil movement
when compared to a blunt opener. The bent leg opener achieved much lower soil
movement while loosening a furrow, and when combined with a single sided
chamfer was able to virtually eliminate throwing of soil out of the furrow and
hence would have no effect on adjacent furrows. The concept of bent leg furrow
openers has the potential to change the dynamics of soil disturbance when
no-till seeding with tine openers.
Solhjou, A. A., Fielke, J. & Desbiolles, J. (2012)
Lateral translocation of surface soil by
various no-till narrow point openers. Agrociencia, 16(3), pp. 336-342.
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