Profitable crop sequences in the low rainfall region of upper Eyre Peninsula


Research organisatons
Funding source

Trial details

Researcher(s) Suzanne Holbery and Nigel Wilhelm (SARDI)
Year(s) 2014
Contributor SARDI Minnipa Agricultural Centre
Trial location(s) Site 2, Minnipa Agricultural Centre, SA
Profitable crop sequences in the low rainfall region of upper Eyre Peninsula locations

To determine the comparative performance of alternative crops and pastures as pest and disease breaks in an intensive cereal phase. In low rainfall regions of south-eastern Australia broad-leaf crops make up only a very small proportion of the total area of sown crops. In light of increasing climate variability farmers have adopted continuous cereal cropping strategies as non-cereal crops are perceived as riskier than cereals due to greater yield and price fluctuations. At the same time, this domination of cereals is increasing the need for non-cereal options to provide profitable rotational crops, disease breaks and weed control opportunities to sustain cereal production. Currently, the most common ‘break crop’ is a poorly performing volunteer annual grass dominant pasture. They are often havens for cereal pests and diseases and are seen as having negative impacts on subsequent cereal grain yield and quality.

Key messages

A break of two years can produce a better financial outcome than continuous wheat over a four year period of production where there are substantial pressures on wheat performance (eg. grassy weeds). Wheat yields after a two year break were a significant step up from wheat crops following a one year break, which were in turn, much better than the continuous wheat. Large break crop benefits of 0.5-1.25 t/ha were achieved following a two year non-cereal break phase compared to continuous wheat. The break crop benefit of a one year break may only last one season if grass weeds are a significant factor. The major benefit of breaks in these long term cereal paddocks was to reduce grassy weed pressures for subsequent wheat crops phases. The benefit of a two year break had little to do with the phases chosen for those two breaks, providing that excellent grass weed control could be achieved in both. Many of the most profitable crop sequences over the four year period often started with a two year break phase.

Lead research organisation South Australian Research and Development Institute
Host research organisation SARDI Minnipa Agricultural Centre
Trial funding source GRDC DAS00119
Related program Crop Sequencing Initiative

We would like to thank Ian Richter and Wade Shepperd for technical expertise throughout the duration of the trial over the past four years. Thank-you Chris Dyson for biometric expertise.

Other trial partners Not specified
Download the trial report to view additional trial information


Crop type Cereal: Wheat
Treatment type(s)
  • Crop: Type
Trial type Experimental
Trial design Replicated
Sow rate or Target density 55kg/ha
Sowing machinery Not specified
Sow date 11 May 2014
Harvest date 30 November 2014
Plot size 2m x 20m
Plot replication 3
Plot blocking Not specified
Plot randomisation Not specified
Paddock history Prior to 2011 > 10 years cereal

65kg/ha 18:20:0:0 Five treatments that had not had any legume break phase (2x continuous wheat, vetch/oats mix followed by wheat, oats then canola and canola then oats) in the previous two years also received 50 kg/ha of urea at sowing to compensate for any extra nitrogen deficiency. On 22 July additional nitrogen was applied in the form of urea. Treatments were assessed using soil mineral nitrogen data and fertiliser application to determine available mineral nitrogen. Treatments with calculated levels of ≤ 100 kg/ha (canola/medic, medic/oats, pea/canola, canola/pea, oats/medic, fallow, medic/canola, medic/regenerated medic & canola) mineral nitrogen received 60 kg/ha urea, whilst treatments with 101-120 kg/ha (pea/oats, pea/wheat, pea & canola/wheat, oats/pea, Angel medic/wheat, Jaguar medic/wheat, sulla, vetch & oats/wheat, canola/oats) received 30 kg/ha. The two continuous cereals treatments and oats/canola had greater than 120 kg/ha mineral&


From grass weed data in 2013 the decision was made to address heavily infested treatments with a pre-emergence mixture of Sakura @ 118 g/ha and Avadex @ 2 L/ha. The treatments were pea/oat, oat/pea, medic/wheat, pea/wheat, pea/canola, pea+canola/wheat. It was hoped that the continuous cereal treatments and the vetch+oat/wheat treatment would have reduced grass numbers having had Intervix applied in 2013. These three treatments and all remaining treatments received trifluralin @ 1.5 L/ha. On the 6 August all treatments were visually assessed for the presence of broad-leaved weeds. As a result all treatments excluding oats/medic, fallow, and medic/oats were sprayed with 2, 4-D (2-ethylhexyl ester) @ 0.6 L/ha.


Four days post-sowing all plots were sprayed with chlorpyrifos @ 0.7 L/ha to address observed cut worms in the trial. Treated grain mouse bait was applied to the trial the same day.


On 15 August as a response to observed stripe rust in the district the trial was aerial sprayed with tebuconazole @ 0.29 L/ha.

Pesticide Not specified
Soil amelioration Not specified
Seed treatment Not specified
Inoculant Not specified
Tillage Not specified
Other trial notes

For greater detail of trial management over the past three years refer to articles EPFS Summaries 2011, p 111, 2012, p 94, and 2013, p 104.

Download the trial report to view additional method/treatment information

Trial results Table 1

# Variety
Treatment 1
Soil N (mg/kg) Hectolitre weight (kg/hL) Screenings (%) 1000 grain weight (g) Weeds (plants/m2) Establishment plants (plants/m2) Protein (%) Grain yield (t/ha)
1 Wheat:Corack 1 WHEAT grain / WHEAT grain 111 85.1 3.5 41 61 81 9.2 3.3
2 Wheat:Corack 2 WHEAT grain / WHEAT grain 90 85.2 3.5 40 41 50 9.1 3.3
3 Wheat:Corack 3 ANG MEDIC seed / WHEAT grain 100 85.7 2.9 41 47 87 9.1 3.7
4 Wheat:Corack 4 VETCH+OATS hay / WHEAT grain 81 84.7 3.5 38 46 64 9.8 3.4
5 Wheat:Corack 5 OATS hay / CANOLA grain 95 85.2 3.3 41 42 67 9.2 3.4
6 Wheat:Corack 6 OATS hay / FIELD PEA grain 98 85.5 3 41 51 92 9.1 3.5
7 Wheat:Corack 7 OATS hay / EARLY SOWN MEDIC graze 82 85.8 3.2 40 74 97 9 3.7
8 Wheat:Corack 8 FALLOW / FALLOW 82 86.1 3 42 13 92 9.2 3.7
9 Wheat:Corack 9 ANG SOWN MEDIC seed / WHEAT grain 101 85.6 3 41 45 91 9.1 3.4
10 Wheat:Corack 10 SOWN MEDIC hay / REG MEDIC+CANOLA graze 85 85.5 2.6 40 22 91 9.3 3.6
11 Wheat:Corack 11 EARLY SOWN MEDIC hay / CANOLA grain 85 85.6 2.7 41 29 90 9.4 3.6
12 Wheat:Corack 12 EARLY SOWN MEDIC hay / OATS graze 79 85.4 2.9 40 28 91 9.5 3.6
13 Wheat:Corack 13 CANOLA grain / FIELD PEA grain 81 85.3 2.9 41 31 92 9.4 3.8
14 Wheat:Corack 14 CANOLA grain / EARLY SOWN MEDIC graze 73 85.5 3 41 22 84 9 3.5
15 Wheat:Corack 15 CANOLA grain / OATS graze 82 85.1 3.5 40 18 74 9.4 3.5
16 Wheat:Corack 16 FIELD PEA grain / OATS graze 92 85.4 2.9 41 28 91 9.2 3.8
17 Wheat:Corack 17 FIELD PEA grain / WHEAT grain 92 85.7 3.3 42 33 96 8.9 3.5
18 Wheat:Corack 18 FIELD PEA grain / CANOLA grain 81 85.5 2.6 41 22 91 9.1 3.7
19 Wheat:Corack 19 FIELD PEA+CANOLA hay / WHEAT grain 95 85.5 2.8 41 18 96 9.2 3.6
20 Wheat:Corack 20 SULLA graze / REG SULLA graze 101 85.2 2.6 40 16 91 9.4 3.6

Grain yield t/ha


1000 grain weight g


Establishment plants plants/m2


Hectolitre weight kg/hL


Protein %


Screenings %


Soil N mg/kg


Weeds plants/m2

Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Site 2, Minnipa Agricultural Centre, SA Red sandy clay loam
Derived trial site soil information
Australian Soil Classification Source
Trial site Soil order
Site 2, Minnipa Agricultural Centre, SA Calcarosol
National soil grid Source
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties



Site 2, Minnipa Agricultural Centre SA 2014

Observed climate information
Rainfall trial gsr (mm) 290mm
Derived climate information
BOM Data source MINNIPA PIRSA [4269] 2km proximity to trial site location


Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from
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.