Brian Dzoma1, Nigel Wilhelm2, Peter Telfer3 and Kym Zeppel1
1SARDI Loxton Research Centre. P O Box 411, Loxton SA, 5333,
2SARDI Waite Research Precinct. Building 11A Hartley Grove, Urrbrae, SA 5064,
3Turretfield Research Centre. Holland Road, Rosedale, SA 5350
Soil compaction on sandy soils is one of the major problems facing modern farming systems because of frequent use of heavy machinery which comes with intensive cropping. Deep ripping on Mallee sands is becoming a common option to reduce hard pans and ameliorate compacted layers. The challenge facing growers is determining the optimal ripping depth and tine spacing for their soils. Aims of this project were to assess the impact of deep ripping on subsoil compaction and performance of several crop species and to determine the optimal ripping depth x tine spacing for Mallee sands. Our trials showed that ameliorating compacted sandy soils in low rainfall environments can lead to improved shoot DM and grain yield, and should subsequently lift farm productivity and profitability. In terms of grain yield, ripping at narrow or wide tine spacing gave similar outcomes and wider tine spacings can therefore be considered in order to use less machinery horsepower. Our trials also show that when the soil in question is compacted to depths beyond 40cm, then ripping deeper is better for grain yield, provided there are no other chemical constraints below the compaction zone.