Authors: Jack Desbiolles1, Chris Saunders1, Chris McDonough2, Michael Moodie3
Research Team: 1 Agricultural Machinery Research and Design Centre, School of Engineering, University of South Australia, Mawson Lakes, SA 5095, 2 Insight Extension for Agriculture, Loxton, SA, 5333. 3 Frontier Farming Systems, Mildura, Victoria 3500
Funded By: GRDC, SAGIT, NLP and SAMDB NRM Board
Project Title: Multiple projects
- Several research and demonstration activities in constrained sandy soils are focussing on improving the adoptability of amelioration practices via spading.
- Results to date show it is possible to improve control over soil erosion risks in spaded areas by directly sowing at the time of spading, using improved seeding opener kits to maximise crop establishment performance in order to stabilise the vulnerable sand.
- It is also possible to modify a spading machine to only spade half its working width, in distinct narrow strips and leave undisturbed areas with surface residue in between, as well as ‘strip-spade and sow’ in one pass.
- An innovative approach to spade strips on harvester trail areas with concentrated crop residue has demonstrated clear grain yield and soil water use benefits.
- Over a cycle of three years, this practice aims to ameliorate a full paddock and represents an inventive pathway to optimise subsoil amelioration with farm grown biomass.
Why was the trial/project undertaken?
Options for sandy soil amelioration in the Southern and Western grain cropping regions of Australia rely on intensive strategic tillage interventions, many of which leave the soil profile loose, soft and exposed. These often once-off interventions include inversion ploughing, delving and mixing by high speed tined implements or rotary spading. In many regions, the adoption of such full soil disturbance operations is limited due to the high risk of soil erosion until a crop is successfully established, the challenges of securing accurate seed placement and leaving a uniform surface finish, which typically result in erratic and poor primer crop establishment. In recent years, rotary spaders have been promoted as effective mixing tools able to operate at depths up to 400mm and producing very significant grain yield responses in a variety of sandy soil contexts (Fraser et al., 2016).
Specific design adaptations such as larger rear press-wheels leaving a consolidated profile with treaded furrows, have been made to reduce the impacts of soil erosion. This paper reports on the results of innovative techniques aiming to increase the farming system benefits and reduce the risks of erosion to a minimum, as a pathway to boost the adoptability of rotary spading in constrained sandy soils.
How was the trial/project undertaken?
This article provides a summary of multiple trials and demonstration undertaken by the number of research and extension authors over the last 4 years at numerous sites across the SA and Vic Mallee. The full paper was presented at the 2019 Australian Agronomy Conference and is found at http://www.agronomyaustraliaproceedings.org/images/sampledata/2019/2019ASA_Saunders_Chris_196.pdf.
PIRSA, SAGIT, GRDC, NLP and NRMDB (SA) funding, local grower collaboration, industry support (Groocock Soil Improvement) and wider support within the respective project teams are all gratefully acknowledged.