Break crops pay

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Two light blue water drops on a darker blue backgroundA vetch break crop increased WUE of the following two wheat crops by 16 to 83 per cent relative to wheat on wheat.

Trials established in 2009 to identify low-risk, profitable break crops for the Victorian Wimmera and Mallee region are delivering promising results, with many outperforming continuous wheat in long-term profit

Including a break crop in a crop sequence is at least as profitable as continuous wheat and in some cases substantially more profitable, according to four years of BCG (formerly Birchip Cropping Group)research trials, which were part of the GRDC Water Use Efficiency Initiative.

Pulse-based break crops can be profitable in their own right while also delivering water use efficiency (WUE) and nitrogen benefits to subsequent wheat crops, which in turn increase subsequent wheat yields and profits compared with wheat/wheat sequences.

Canola break crops lift farm profits and offer disease and weed benefits but generally do not deliver water and nitrogen benefits to following wheat crops. The trials have highlighted the importance of determining the ongoing impact of break crops on the profitability and WUE of wheat systems.

Break crop trials planted in rows

Including a break crop in a crop sequence can significantly lift the water use efficiency and profitability of wheat production systems.

PHOTO: Dr James Hunt, CSIRO

For example, while legume hay was not as profitable as wheat or canola in the year it was sown, the break crop’s impact on soil water and nitrogen lifted the overall profitability of the legume/wheat rotation beyond that of a wheat/wheat sequence.

In some instances the impact of a legume break crop lasted several years.

The trial was carried out south-east of Hopetoun, Victoria, on sandy and clay soil types. At each site break crops and wheat were grown in three different sequences over three seasons from 2009–12 and the yields and profitability of each of the sequences were compared to a continuous wheat program. Break crops grown included a fallow and canola, peas grown for either grain or hay and vetch grown for either hay or brown manure.

The type and end-use (grain, hay or brown manure) of the break crops grown in 2011 influenced 2012 wheat yields. Wheat also yielded more following hay crops of canola, wheat and pea at the sand and clay sites, probably due to the extra soil water made available by the early termination of these crops (Table 1).

Table 1: 2012 wheat yields following either a short or long fallow and break crops in 2011. Break crops were grown for grain, hay or brown manure (vetch only). Growing season rainfall for 2012 was 150mm following 90mm of summer rain in 2011–2012
2011 crop
Sand Clay
Canola 4.5 5.4 1.9 3.4
Fallows 5.2* 5.4** 4.2* 4.2**
Peas 4.9 5.6 3.1 4.0
Vetch 5.3^ 5.4 4.0^ 4.4
Wheat 3.9 5.2 2.4 3.8
* Short fallow
** Long Fallow
^ Vetch grown as brown manure not grain

Profitability of crop sequences

Graph representing average two-year gross margins ($/ha)

FIGURE 1: average two-year gross margins ($/ha) on the clay and sand sites of a fallow or break crop grown in 2011 as grain, hay or brown manure (vetch only) followed in 2012 by Correll wheat.

At the sand site canola grain, vetch hay and pea hay followed by wheat were as profitable as continuous wheat (Figure 1).

Wheaten hay followed by wheat grain was also a profitable crop sequence at both sites. This was largely because of good hay prices in 2011 and above-average grain yields due to the extra soil moisture made available following the hay crop, as well as strong 2012 grain prices. At the clay site, all crop sequences were at least as profitable as wheat on wheat (Figure 1).

The economic risk associated with producing break crops can be reduced significantly by remaining flexible about their end-use – grain versus hay or mulch. Such flexibility will conserve valuable soil moisture for the following wheat crop.

Related Videos

Still of the GCTV Break Crops video

Proof that Break crops Pay: What's the yield benefit to your wheat crop from a broadleaf break crop? Trials by research group BCG shows the benefit is significant. BCG's Claire Brown features in this video.

More information:

Claire Browne, executive officer, BCG,
03 5492 2787,

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GRDC Project Code CPS00111, BWD00012, CSA00025

Region South