Jeff Russell
Dryland Research Institute, Box 432, Merredin, WA 6415
Canola (Brassica napus L) production in the low rainfall (< 325 mm) central eastern district of Western Australia is in its infancy. There are very few growers who have more than three years experience. Given favourable returns, canola production and adoption has grown rapidly in the last few seasons.
District benchmarks endeavour to provide growers with a comparison of their own canola production inputs and outcomes against those with farmers in a similar environment. They are extremely valuable for novice growers as they give them a guide to what targets need to be, or can be achieved with their peers. For more experienced growers these benchmarks are the first step in helping to develop district best management practices.
In 1998 and 1999 canola growers in the low rainfall central eastern district of Western Australia were surveyed as to the performance of their canola crops of the respective season. Information gleaned from these surveys is summarized and covers a wide range of parameters from yield to fertilizer and herbicide use. From this gross margins and production efficiencies were calculated. Differences between the two seasons and trends in the various benchmarks surveyed are outlined. The results are then used to assist in the future development of the industry within the district.
low rainfall, best practice, industry development
Canola production in the low rainfall central eastern wheatbelt has experienced a dramatic increase over the last few years. In 1996 the estimated area in production was close to 1 000 ha for the entire central region. By 1997 this had risen to 29 000 ha and in 1998 to an estimated 60 000 for the eastern district (unpublished data). Much of this increase has occurred as a result of the good returns delivered to growers and the development of triazine tolerant and short season varieties of canola.
As a result of this growth there are many novice growers attempting canola in the district. With this comes the need for assistance in general crop agronomy. Benchmarks are useful for new growers wishing to attempt growing canola. They give useful indicators as to the level of inputs required to grow a successful crop and the likely yields that can be realistically achieved in the district.
Canola growers were surveyed at the end of each of the 1997 and 1998 seasons. The form of the survey took place as a mail out to known growers within the district. The survey form consisted of a simple recording sheet from which could be transcribed the records of a canola paddock pertaining to crop husbandry and agronomic procedures. 21 respondents to the survey were used in 1997 and 19 for the 1998 season.
Information from the survey sheets was collated to determine mean data and the ranges for the various parameters assessed. From this data, gross margins for canola were derived. This figure was determined from the input costs being deducted from the return achieved on a per hectare basis. Costs were established from known inputs and a general estimate of the variable costs. This variable cost was estimated at $60/ ha and used to cover input costs such as cost of seed, insurance, labour, interest, machinery repairs and maintenance, fuel and oils.
Specific costs of herbicides, pesticides and fertilisers could be calculated directly from the information given from the survey. Actual costings were based on figures given in the Farm Budget Guide (Agriculture WA, 1997 and 1998). Likewise canola price was calculated based on oil and admixture standards using a CBH code (Grain Pool, 1997 and 1998). Price for canola in 1997 was based on $348/t at 40% oil and for 1998, it was $400/t at 42% oil. Freight costs from the farm gate were not included in the calculations. As such a general “ball park” estimate of the likely rates of the various fertiliser and pesticide inputs for the district is derived, from which the profitability of the crop is calculated for both seasons. These inputs and resultant outputs are then used as “Industry Benchmarks” for the growers in the district.
A summary of the major benchmarks is shown in Table 1 below, along with seasonal and cultural information.
Table 1. Industry benchmarks for the central eastern district of Western Australia.
|
|
1997 |
1998 |
|
Number of replies |
21 |
19 |
|
Average growing season rainfall (mm) |
214 |
289 |
|
Predominant soil type |
Sandy surfaced soils |
Sandy loams |
|
Yield (t/ha) |
Top: 1.53 Average: 0.88 |
Top: 1.5 Average: 0.81† |
|
Oil Content (%) |
Range: 35 - 43.7 Average: 39.7 |
Range: 34 - 46 Average: 41.5 |
|
Gross Margin ($/ha) |
Top: $341 Average: $140 |
Top: $398 Average: $146 |
|
Variety (most common) |
Karoo (90%) |
Karoo (95%) |
|
Sowing Date |
Range: 8th April - 18th May Average: 26th April |
Range: 14th April - 7th May Average: 25th April |
|
Seeding Rate (kg/ha) |
Range: 3.75 - 8 Average: 5.6 |
Range: 2.5 - 8 Average: 5.6 |
|
Fertiliser Costs ($/ha) |
Range: $44 - $85 Average: $66 |
Range: $26 - $81 Average: $60 |
|
Average Fertiliser Units (/ha) |
Following cereal: N - 46.4 units P - 16.5 units S - 13.2 units
Following legume: N - 40.5 units P - 20.5 units S - 16.8 units
|
Following cereal: N – 47.2 units P – 11.0 units S – 12.3 units
Following legume: N – 44.8 units P – 10.7 units S – 13.9 units
|
|
Herbicide Costs ($/ha) |
Range: $10 - $52 Average: $29 |
Range: $8 - $53 Average: $30 |
|
Insecticide Costs ($/ha) |
Range: $4 - $52 Average: $15 |
Range: $0 - $18 Average: $7.50 |
|
Water Use Efficiency* (% of potential yield) |
Range: 25% - 89% Average: 69% |
Range: 14% - 52% Average: 30% |
*Based on April to October growing season rainfall. In 1997 there was some contribution of autumn rain to crops.
† 50% of 1998 crops surveyed were affected by frost.
Each season’s results needs to be understood in the context of the individual season. Seasonal variability can not be controlled. Both seasons were characterised by very early starts compared to the “traditional season break” in the district of May 22. The 1998 season had greater rainfall, as such the potential crop yields were expected to be greater. However, some reports of water-logging mid season and late frosts in September attributed to the fact that many crops did not achieve their true potential and hence had a lower water use efficiency (WUE). Frost did affect the 1997 crop but it occurred midway in the season and the canola was able to compensate for any damage to yield. Also in 1997, late March rains contributed to stored moisture reserves for many crops. As a result there is a greater WUE for the crop grown in 1997.
Similarities exist for both seasons. The predominant variety is Karoo, which is triazine tolerant. This allows growers to capitalise on such early starts. However, Karoo is of mid season maturity and given the frost problems, hindsight is suggesting that a longer seasoned variety may have been more appropriate. While the average sowing date was of little difference, the 1998 season had a cooler finish. This would have assisted in achieving the higher oil content of the crop in that year.
In both years fertiliser and herbicide costs were similar. This is not too surprising for herbicides as using the variety Karoo would have similar herbicide regimes. What is of interest is that while the amount of N applied to the crop did not change substantially, the level of P and S dropped in 1998. This is likely due to the use of less compound fertilisers at seeding. In 1997 N toxicity was experienced by many growers. The early start was followed by a dry period in the month of May causing crop establishment to be affected. Learning from this, growers in 1998 applied less fertiliser at seeding. The difference in N being made up later in the season with a greater amount being top dressed as urea.
Insecticide costs in 1998 were half that of those in 1997. This being mainly due to aphid and budworm not being as prevalent as they were in 1997. The main cost of insecticides in 1998 was for early control of insects at crop establishment. Lucerne flea being the greatest problem in that year.
These benchmarks provide a useful insight as to how the canola industry is progressing within the low rainfall eastern district of Western Australia. The benchmarks serve as an industry standard for both novice and existing growers to outline what can be achieved and the likely levels of inputs required to grow a profitable crop.
The assistance of the 21 and 19 growers who replied to the surveys in 1997 and 1998 is greatly appreciated.
Agriculture W.A. 1997. Farm Budget Guide 1997. Compiled by Agriculture Western Australia, Published by Farm Weekly.
Agriculture W.A. 1998. Farm Budget Guide 1998. Compiled by Agriculture Western Australia, Published by Farm Weekly.
Grain Pool of WA. 1997. The Grain Pool of WA Receival Standards, 1997/98 season.
Grain Pool of WA. 1998. The Grain Pool of WA Receival Standards, 1998/99 season.