In 2015, the area sown to canola was substantially reduced from that of the past three seasons. With  the disappointment of the 2014 season and the less than promising start to 2015 (lack of soil moisture and a forecast El Nino), growers were more than justified in opting out of canola.
While the benefits of growing canola are well understood, it is vital that growers set rules before they do so. One such is the need for at least 30-50mm of plant-available moisture in the soil. Nevertheless, the benefits of canola in the cropping system as a weed and disease break cannot be discounted: even under unfavourable seasons, canola still has a role in farming systems.
New technology, such as the RoundUp Ready® (RR) and RoundUp Triazine (RT) tolerant varieties, has stimulated grower interest. Before deciding on a variety, it is important to explore any additional costs and whether those costs outweigh the benefits and/or add greater risk.
This article will summarise canola trials in 2015 and provide insight into the costs incurred and profitability achieved from growing canola.
TAKE HOME MESSAGES
- Early maturing varieties such as NuSeed Diamond and 44Y89CL produced the highest yields.
- Roundup Ready® canola has a lower return on profitability, but enables early multispectral
control of weeds and allows for two herbicide applications. - Canola can be an extremely valuable tool for growers to use for weed management. Using
both chemical and non-chemical practices wisely and affordably will ensure growers get
the best results from canola. - Growers who decided not to sow canola in 2015 due to lack of sub soil moisture made the
right decision.
AIM
To independently assess the performance of existing and emerging canola varieties.
TRIAL DETAILS
Location: Nhill
Soil type: Clay
GSR (April-Oct): 124mm
Varieties: See Figure 2
Sowing dates: 23 May
Seeding equipment: Knifepoint, press wheels, 30cm row spacing
Target plant density: 40 plants/m2
Harvest date: 2 December
Trial average yield: 0.7t/ha
TRIAL INPUTS
Fertiliser:
Granulock Supreme Z + Impact (200ml) @ 60kg/ha at sowing plus SOA @
50kg/ha at cotyledon (1 June) and urea @ 60kg/ha at 2-4 leaf (23 July).
Weeds were managed according to their herbicide group. Pests were controlled to best management practice.
METHOD
Three replicated field trials were sown at Horsham, Berriwillock and Nhill. Two of these are not represented here due to the severe seasonal conditions: the Berriwillock site was not harvested because of minimal rainfall and bird damage, and the Horsham results were not meaningful or scientifically valid because of low yields and high variability.
At the Nhill site, varieties were blocked according to their herbicide group. In-season assessments consisted of emergence scores, grain yield and quality assessments were made through the season. To ensure that all varieties were suitable for harvest, the plots were desiccated. The timing was based on the standard variety within the trial.
Prices for GM canola and non-GM canola were obtained on 19 November from Murtoa GrainCorp receival site.
RESULTS AND INTERPRETATION
The Nhill trial was sown into a chemical fallow paddock with 22mm PAW (soil sampled in March). In January, the site received 70mm rainfall. These together certainly made the paddock suitable for growing canola.
The annual rainfall for Nhill in 2015 was 226mm, far below the long term average of 402mm. The season was followed by a decile 1 rainfall, which obviously did not favour canola sown without subsoil moisture. April to July rainfall of 62mm and the additional stored moisture from the fallow period meant that many of the early maturing varieties grew well through to budding and early grain fill. Conversely, the later maturing varieties were adversely affected by the early onset of heat and suffered a yield penalty, Table 1.
There was 102kg N/ha of nitrogen (N) in the profile, sufficient to support the yield potential of the canola when combined with top dressing. The site experienced both heat stress and frost during the year. It should be noted that both a frost (-0.5°C) and a heat event (34.1°C) occurred in Kaniva on October 14 (Figure 1).
Given the decile 1 conditions, the late maturing varieties clearly struggled with the minimal rainfall and hotter than average temperatures in the first week of October. Early maturing varieties like IH30RR and NuSeed Diamond flowered early whilst conditions were still mild, avoiding the hot beginning of October. The region did not experience severe frosts in 2015, (as occurred in 2014) and as a result the early maturing varieties were best adapted to this growing season in terms of setting yield potential and test weight.
The warm dry conditions in August had an effect on the varieties, including the early maturing
varieties (ATR Stingray, IH30RR and Clearfield 43C80) but was more apparent on later maturing varieties. Excessive heat and reduced rainfall during the reproductive phases is certain to reduce seed quality and production in mid-late maturing varieties.
The variety NuSeed Diamond was a standout in 2015 as well as 2014 (Figure 2), but the conventional weed control options associated with hybrid NuSeed Diamond must be considered. NuSeed Diamond does have excellent early vigour which was seen in the trial: it adapted well to the short growing season.
However, the presence of weeds affects yield significantly. The newly listed canola varieties for 2015 included in the Nhill variety trial were 44Y89CLF, 45Y25, IH51RR, IH52RR, and Monola 515TT. All of these new varieties exceeded their herbicide group average yield apart from Monola 515TT.
Roundup Ready® IH51RR has the new Pod Guard™ technology reduction trait. Pod Guard is a new Bayer CropScience trait which has the ability to strengthen canola pods to reduce the risk of shattering and consequent pod loss. This variety is mid maturing and had a yield of 0.8t/ha which was higher than the average RR yield of 0.74t/ha (Figure 2.). Although suited to medium to high rainfall areas, this variety performed well considering the conditions. The other extra bonus of the Pod Guard technology is that it allows for increased flexibility for windrowing and direct harvest opportunities. IH51RR is a canola variety to watch very closely.
In terms of grain quality, the mean test weight was 62kg/hL, the minimum specification for canola (>62 kg/hL). Generally, those varieties that yielded well had better test weight than those that didn’t. The commodity standard for canola oil is 42 per cent with a 1.5 per cent premium or deduction of each one per cent under or over 42 per cent. The average oil per cent for the trial overall was 37.7 with a range from 35.15 per cent to 41 per cent. Higher oil content was frequently found in higher yielding varieties.
COMMERCIAL PRACTICE
This season and the results of these trials, highlighted that without stored soil water and confidence in the season’s rainfall, canola is higher risk than other crops. With good soil moisture and optimism about the season, there is still a place for canola in crop rotations. The costs of growing canola can vary greatly: it is important these are understood and where possible reduced to the necessary inputs only. This will ensure the risk is worth the reward.
Though it failed to provide growers with increased yield in this trial, the performance of the new  variety Hyola 525RT, needs to be put into context. Growing RT varieties is an option only if other weed control techniques are no longer effective. Keep in mind that there are plenty of other non-herbicide approaches that can be used to manage weeds such as crop-topping and narrow windrow burning. Nevertheless, it is a yet another tool available for growers in the never ending war on weeds.
ON-FARM PROFITABILITY
NuSeed Diamond yielded 1.1t/ha and was the most successful in a decile 1 season. If delivered to Nhill it would have returned an income of $586/ha.
Profitability of canola is often a grower’s greatest frustration. However, understanding the costs and minimising these where possible can improve profitability greatly, as well as choosing herbicide groups based on the weed spectrum in the paddock.
While canola was ‘on the nose’ in 2015 due to lack of soil moisture, there may have been cases where growers are keen to investigate its potential profitability. To compare the gross margins for each of the herbicide groups TT, RR, RT and CLF to provide some guidance on the overall costs involved, use the RR canola variety comparison tool (https://www.roundupreadycanolavarietycomparison.com.au) to determine the gross margin based on the costs of the chosen herbicide groups.
REFERENCES
GRDC Victorian Winter Crop Summary 2015.
ACKNOWLEDGEMENTS
This trial was funded by BCG members through their membership.
