To rip on or off the old rip line: a paddock-scale study on deep ripping and topsoil inclusion in a dry season

Key messages

1. Deep ripping sands with topsoil inclusion to 45cm increased canola yield on the rip line compared to off the rip line by 24–66% in a decile 1 rainfall season (123mm growing season rainfall achieving 100% of estimated yield potential).
2. Four years after ripping, the topsoil inclusion had created a pathway of better soil pH and lower bulk density for more roots down the rip line through the compacted, acidic and aluminium-toxic subsoil — increasing organic carbon levels to 40cm depth and root access to deeper moisture and nutrients.
3. Plant and soil measurements suggest that subsequent deep ripping with topsoil inclusion in the ‘off row’ to alleviate compaction, could improve pH and nutrition/organic matter. Creating an inclusion zone every 30cm would give each crop row close proximity to a rip line of better fertility and access to moisture each season further increasing yield and the longevity of the ripping benefit.