EASTERN Wheatbelt growers have commonly experienced adverse seeding conditions over the past few seasons, particularly in heavy textured soils.
The correct seeding setup (sowing depth, seeding boot and press wheel) leads to an even crop germination that tends to produce higher crop yields and profit.
This greatly affects grower profitability as issues tend to arise later in the season with spray timing and wind erosion on non-germinated/late germinating areas.
In addition, time of germination has become critical in the eastern Wheatbelt due to a trending drying spring climate.
Heavy textured soils are proving to be among the most challenging soils to manage in varying seasonal conditions in the eastern Wheatbelt.
Correct furrow closure ensures uniform seed-to-soil contact and optimum packing in the seed zone to promote moisture with the seed and prevent surface light penetration.
Furrow closing is critical to optimising crop establishment and seed bed characteristics, especially on heavy textured soils.
Factors such as poor seed-to-soil contact from insufficient press wheel pressures on puggy or cloddy clays and the level of soil compaction from heavy rainfall often lead to varying and uneven crop emergence and poor plant vigour.
Having the airseeder set-up correctly is critical for rapid seed germination, uniform crop emergence and good early crop vigour.
To increase crop establishment it is not just a case of swapping knife points and press wheels for a disc seeder system.
One challenge faced by eastern Wheatbelt growers is their ability to maintain a consistent and accurate seeding depth across their varying soil types.
As a result crop establishment is often variable with crops sown too shallow or deep and with insufficient furrow closing.
During 2018, the Corrigin Farm Improvement Group (CFIG) identified and implemented a trial site north east of Corrigin.
The concept of this project (which is in its second year)is to compare a range of furrow closing systems and packing pressures (both common and unique to the area) and to determine which closing system would be more productive on the medium to heavy textured soils of the eastern Wheatbelt.
CFIG has chosen to focus on tyned airseeders as they are the most commonly used system in the region.
The group established a one hectare trial site to assess a range of furrow closing options (4) and down force pressures (2).
These included the following press wheels at two down force pressures - five kilograms and 30kg per press wheel - over W shape, Emu Tracker, Wedge and V Shape press wheels.
Crop emergence and vigour was good early in the season due to having sufficient rainfall prior to seeding of the trial to allow for even emergence of barley plants.
Come harvest on November 28, the V shape with a lower down force pressure had the greatest yield of 3.84 tonnes a hectare and the V shape with a higher down force pressure had the lowest yield of 3.47t/ha.
Even though there was no statistical difference (P=.92), there is a difference of 370 kilograms a hectare between the highest yielding and lowest yielding treatment.
Interestingly, the lower down force pressure across all press wheel type treatments yielded higher than the high down force pressure treatments, although this was not statistically significant.
Over a large area this could equate to a large enough difference to impact the gross return, being reason for a grower to change press wheel pressures.
In terms of gross return, the W shaped press wheel with a lower down force pressure had the greatest gross return of $974.43/ha, whilst the W shaped press wheel with a higher down force pressure had the lowest gross return of $814.15 per hecatre.
This is a difference of $160.28/ha.
Grain quality could account for the major difference in gross margin when compared to yield difference between press wheels and pressures.
The trial is now in its second season in 2019 and the group continue to measure crop emergence, yields and grain quality across the eight treatments.
The conditions at seeding this year were very different to last season and the group expects to see varying results this year due to dry soil conditions at seeding causing clodding and poor soil seed contact in early June.
This project is a Grains Research and Development Corporation investment and CFIG would like to thank host grower Ashley Jacobs for his time and effort.