This is the result of a deep ripping trial, held at Pinnaroo, where Williamson-Agri CT Ripper was used . The photos show that the soil surface resulting from our ripper was much more level and had improved trafficability.
Post ripping rolling improves trafficability and seeding at Pinnaroo
Paddock trafficability post ripping is a major constraint to the implementation of deep ripping on a commercial scale. Seeding and spraying operations are particularly affected which can lead problems such as poor establishment, machinery damage and in some circumstances soil erosion. A new trial has been established by MSF near Pinnaroo in 2020 to investigate solutions to this problem. The trial is part of the project “Deep ripping to enhance production on Mallee Sandy Soils” which is funded by SAGIT.
The trail is measuring the effect two different deep rippers (Hanton and Sharrad ripper fitted with straight shanked Tilco tine and a Williamson Agri ripper fitter with curved Michel tynes) and rolling on trafficability, seed depth and crop establishment. The trial was sown commercially by the collaborating farmer using a Horwood Bagshaw PSS system. A 3D map of the trial site post sowing shows that treatments had a significant effect on the soil surface condition post sowing.
Figure 1. 3D map of the trial showing difference in soil surface condition from different treatments post sowing.
The trafficability following ripping was measured by driving a Landcruiser ute across the surface immediately prior to seeding and then measuring the depth of the ruts left by the tyres. Un-ripped treatments had shallow ruts of 40-50 mm but were 120 mm following deep ripping with both ripper types (Figure 2). Consolidating the ripped surface with a roller reduced rut depth by 50% (Figure 2). The rut depth data correlated with seeding depth data with wheat seeds from un-ripped and ripped and rolled treatments emerging from 20-30 mm depth while unconsolidated ripped treatments emerged from 50 mm for the curved Michel tine and 60 mm for the Tilco straight tine (Figure 2).
The position of the tine on the bar also affected the seed depth. Where tines at the back of the seeding bar work excessively deep, they may throw soil onto adjacent rows sown with tines from the front of the bar. This will increases the depth at which the seeds need to emerge from and may also carry pre-emergent herbicides into the seed row. In this trial seeds were germinating from 75 mm depth from rows sown with the front tyne but only from 45 mm when sown with a back tine (Figure 2). This effect resulted in a 16% decrease in wheat establishment and reduced early vigour of the deep sown rows.
Figure 2. Data collected from ripping x rolling treatments: depth of wheel rut (left); seeding depth of wheat seedlings (middle) ; seeding depth of wheat seedlings in un-rolled treatments for tines at the front or back of the seeding bar (right).