The aim of this project is for the Corrigin Farm Improvement Group (CFIG) to compare the profitability of a range of crop rotations, including chemical fallowing, on a medium textured, loamy soil type east of Corrigin. Gross returns are assessed both on an annual basis and on an accumulative multi-year basis.
This project was designed to test the relative benefit of chemical fallow with a range of different crop types. The trial compared different crop types on chemical fallow with the aim to identify which crop is likely to produce the highest return. The project also aims to investigate the profitability of different rotations over multiple years which include both chemical fallows and continuous crop.
Key messages
Two significant weather events that had an important influence over the results in this project, in 2016, frost and 2017, summer rain. In 2016, there were multiple severe frost events during the critical, flowering stage of the growing season. Oats being a relatively frost tolerant species proved to be the best performing species for yield and gross returns in 2016. The broadleaf crops, both legumes and canola were severely impacted by frost.
For barley in 2016 the accumulated gross returns for two years was higher in rotation, fallow 2015; barley 2016 when compared with wheat 2015 barley 2016. This supports previous work by CFIG that including fallow in the rotation can increase gross returns over a two year period.
In season 2017 frost damage was minor when compared to 2016. Season 2017 was dominated by heavy summer rainfall and a very dry start to winter. The fallow plots were impacted by the summer rain due to lack of soil cover. The loamy, morrell soil set hard at the surface as a result of the heavy summer rain which severely impacted penetration of the seeding equipment and subsequently, crop establishment was poor. The very dry start to the season likely exacerbated the poor establishment on the fallow plots.
Oats performed well again in 2017 in terms of yield but barley produced higher gross returns. Chickpeas and lentils were the best performing of the broadleaf crops in 2017.
When the gross returns in 2017 were compared by rotation (2015-2017), it is interesting to note that 2017 cereals grown in rotation with legumes in 2016 generally performed well.
The gross returns for every rotation tested in the trial were compared on an accumulative return over 3 years (2015-2017) and the rotation with the highest accumulative return was year 1; wheat year 2; chickpeas and year 3; barley. This demonstrates the value of a legume in a rotation which contributed to the highest yielding plot, which was barley in 2017.
The top two highest total gross return rotations over three years had a legume crop in one year of the rotation. The third highest return rotation had a fallow phase which confirms fallow as a rotation option. In the top 10 highest returning rotations, 4 had fallow in one year of the rotation.
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.
Trial report and links
2016 trial report
GRDC Final Report
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Event
Date
Type
Effect
Frost Damage
In 2016, there were multiple severe frost events during the critical, flowering stage of the growing season. Oats being a relatively frost tolerant species proved to be the best performing species for yield and gross returns in 2016. The broadleaf crops, both legumes and canola were severely impacted by frost.
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There was a significant number of damaging frost events at the trial site during the vulnerable stages (crop flowering and grain fill). Between July and October the minimum temperature for a 24 hour period fell below zero on 29 occasions (Appendix 1). Assessments of frost damage to wheat and barley are included in the results section. The severity and number of frosts during the season is likely to have cause weakening of stems, particularly the canola, and subsequent lodging of plants. The frost also caused major flower abortion of all the broadleaf crops including canola, Albus lupins, lentils and chickpeas.
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July - October 2016
Severe frost
N/A
Summer Rain
The total rainfall (Jan to Dec 2017) of 384.5mm is above average when compared with the long term average of 309mm at Bendering weather station (25km east of trial location). While the growing season rainfall (April to October 2017 of 187mm is below average when compared to the long term average of 235.2mm at Bendering. (Appendix 1) 35mm and 30mm of rain fell in September and October respectively. This would be considered a desirable finish to the season by local growers. Summer rain prior to the season was plentiful, between January and March 2017 total rainfall amounted to 172.75mm.
It is likely that the heavy summer rain (172mm) caused compaction on the bare surface of the 2016 fallow block. These morrell loam soil types can be susceptible to slaking, due to low organic matter. During the soil moisture testing it was observed that the topsoil for the bare fallow blocks was hard set and difficult to penetrate with auger. Also the small plot seeder did not have capability to penetrate the hard topsoil and place seed into moisture – this was exacerbated by a very dry start to the growing season.
