Craig Topham and Bindi Isbister
Site 7, Mullewa, WA
Growers and advisers have a better understanding of the benefits of deep ripping and in particular depth of deep ripping required to optimise crop yield & profit. They also better understand where the cost is worthwhile (rainfall zones, soil types) and very importantly how long the benefit lasts for in a CTF system.
Growers and advisers will be able to assess the likely cost-benefit to them/their clients of deep ripping.
Deep ripping to 500-600mm in coarse textured sandy soils increased yield by 21-66% compared to 6-24% with ripping to 300mm in wheat and canola in 2016 and 2017 in the Geraldton port zone. There was only a small yield response to ripping the red loam in 2016 and no difference in 2017.
Soil moisture measurements and visual observations of plant root growth indicated deeper ripping allowed the plant roots to access more water from deeper down the soil profile. This is particularly beneficial in sandy soils that have a low plant available water capacity(PAWC) per 10cm down the profile therefore roots need access deeper into the soil profile to gain the same amount of water as heavier textured soils that have a higher PAWC per 10cm.
Economic analysis found the higher cost of deeper ripping gave a positive return on investment up to $5/ha for every dollar invested at 3 sandy sites but not on the red loam where the return on investment was negative with a return of $0.63/Ha for every dollar invested. On the sand at Ogilvie there was a yield penalty in lupins in 2016, resulting in a negative return on investment which could not be recouped in the following dry season of 2017.
If ripping below 400mm, consideration must be given to crop selection in year one (lupins are higher risk); leaving an even seed bed post ripping to reduce bogging and plant establishment issues; and managing weeds as due to poor competition and better access to water and nutrients can increase the weed burden as these factors can have a negative impact on yield reducing the return on investment.
|Lead research organisation||
Grains Research and Development Corporation
|Host research organisation||
|Trial funding source||GRDC GER9|
Regional Cropping Solutions Network
Thank you very much to the host farmers Ben Cripps, Paul Messina, Spring Park Farms, Matt Freeman and Braden Bagley.
Thank you to DAFWA GRDC funded project DAW00243 for providing advice on trial setup, assistance with soil compaction assessments and result interpretation.
|Other trial partners||Precision Agriculture|
|Sow rate or Target density||canola|
controlled traffic farming system 3:1 ratio 40ft header, 60ft seeder, 120ft sprayer 36.4, 6.05m ripper
|Sow date||28 April 2017|
|Harvest date||Not specified|
|Plot size||36m x 500m|
|Plot replication||Not specified|
|Paddock history||2017 Canola 2016 wheat 2015 wheat|
||Grain yield (t/ha)|
|1||█ Wheat||█ Yellow sand Ogilvie||█ No rip||2.05|
|2||█ Wheat||█ Yellow sand Ogilvie||█ Shallow||2.14|
|3||█ Wheat||█ Yellow sand Ogilvie||█ Deep||2.28|
|4||█ Wheat||█ Yellow sand Ogilvie||█ Deep +||N/A|
|5||█ Wheat||█ Yellow loam Arrino||█ No rip||2.08|
|6||█ Wheat||█ Yellow loam Arrino||█ Shallow||2.29|
|7||█ Wheat||█ Yellow loam Arrino||█ Deep||2.58|
|8||█ Wheat||█ Yellow loam Arrino||█ Deep +||N/A|
|9||█ Lupins||█ Pale sand Walkaway||█ No rip||0.92|
|10||█ Lupins||█ Pale sand Walkaway||█ Shallow||1.23|
|11||█ Lupins||█ Pale sand Walkaway||█ Deep||1.34|
|12||█ Lupins||█ Pale sand Walkaway||█ Deep +||1.38|
|13||█ Lupins||█ Yellow sand plain Eradu||█ No rip||N/A|
|14||█ Lupins||█ Yellow sand plain Eradu||█ Shallow||2.38|
|15||█ Lupins||█ Yellow sand plain Eradu||█ Deep||2.55|
|16||█ Lupins||█ Yellow sand plain Eradu||█ Deep +||2.3|
|17||█ Canola||█ Red Loam Mullewa||█ No rip||0.85|
|18||█ Canola||█ Red Loam Mullewa||█ Shallow||0.87|
|19||█ Canola||█ Red Loam Mullewa||█ Deep||0.84|
|20||█ Canola||█ Red Loam Mullewa||█ Deep +||N/A|
|Rainfall avg ann (mm)||333mm|
|Rainfall trial total (mm)||381mm|
|Rainfall trial gsr (mm)||166mm|
SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.