Evolving "best management practices" are proving to be the key to successfully incorporating faba beans into southern irrigated crop rotations, reports Rachael Whitforth, extension agronomist with NSW Department of Primary Industries
[Photo (left): Faba beans on raised beds following a five-tonne wheat crop]
Over the past five years there has been renewed interest in irrigated faba beans, because varieties with improved disease resistance have been developed and disease management packages have been put in place.
In the Riverina district, an achievable yield for irrigated faba beans is four to five tonnes a hectare, making them a worthwhile component of irrigated crop rotations. Although often considered more risky and less profitable than wheat, their high-yield potential and the benefits they provide to the following wheat crop make them an attractive option.
From 2000 to 2004 a benchmarking program, "Faba Check", has provided a way of comparing and assessing the role of farm management in faba bean performance.
Growers" increasing experience has seen a general rise in faba beans planted in southern irrigation districts since 1999, as seen in Figure 1. The main reasons for this increase are improved varieties, new management strategies for disease and a better understanding of overall best management practices. "Faba Check" has enabled us to identify the key management practices needed to achieve high yielding, good-quality irrigated faba beans.
Although seasonal conditions play a large part in determining the overall yield and quality of faba beans, growers who followed best management practices over the past five years have consistently achieved high yields and good quality. The keys to their success have been a good irrigation layout, a commitment to frequent watering in the spring and a strategic fungicide strategy - even in dry years.
District crops were first benchmarked in 2000, and for many growers it was the first time they had grown faba beans. Yields ranged from 1.5t/ha to 5.5t/ha, averaging around 3.75t/ha. Boundaries were tested by growing fabas on the flat, with rain after the first spring irrigation causing considerable damage. The two biggest yield factors in 2000 were waterlogging in the spring and lodging at harvest.
Lodging at harvest was a bigger problem on beds because plants were harder to pick-up from furrows.
In 2001, below average rain throughout most of the winter put crops under moisture stress towards the end of July and early August. Some crops lost yield potential as they awaited the start of the irrigation season.
The dry conditions and improved disease management strategies kept the incidence of disease low. District yields ranged from 1.5t/ha to 6.2t/ha, averaging 3.75t/ha to 4.0t/ha. These crops were grown with five to six fungicide sprays.
In 2002, the uncertainty of faba bean prices at the beginning of the season, rotational constraints and good wheat prices saw a decline in faba bean plantings and no "Faba Check" report was compiled.
In 2003, the Agrinational Marketing Pool was introduced for local faba beans (now offered under the name of Ecom Commodities). Crops committed to the Pool had an acreage commitment only. Locally dedicated receival facilities and attractive payment terms saw an increase in the area of faba beans grown.
District yields in 2003 ranged from 2.0t/ ha to just over 6.0t/ha, averaging 3.75t/ha to 4.0t/ha. The district"s top yielding crop, grown on raised beds on self-mulching black soil near Widgelli, east of Griffith, yielded 6.2t/ha. These crops were grown with four to five fungicide sprays.
not to sow too early:
There was limited "Faba Check" data in 2004, but district yields showed mixed results, with yields around eight to 10 per cent down on previous years, possibly due to the hot conditions experienced in September to October. Crops on beds generally received two to three spring irrigations.
One of the biggest issues in 2004 was heliothis (now known as helicoverpa) with the majority of crops needing to be sprayed
While wheat remains the main winter crop grown in the area, faba beans have become an integral part of the irrigated cropping rotation in this district. Since 2000, there has been a move towards more suitable layouts for faba beans, with a higher proportion of crops now grown on beds compared to the flat. Faba beans grown on beds have consistently out-performed faba beans grown on any other layout. Also since 2000, growers have adopted a well-planned disease management strategy and are prepared to spray four, five or even six times for disease, depending on seasonal conditions. This has meant that the build-up of disease during winter is effectively being prevented.
Strategic fungicide applications adopted by district growers are:
"Faba Check" has identified the main factors for succeeding with irrigated crops. The program has put faba beans in context with other crops as requiring a higher level of management input than other winter crops. By benchmarking crops against others in the district, growers are able to see where improvements in their management systems can be made.
GRDC research code DAN00034
For more information: Rachael Whitworth, 02 6963 6926, firstname.lastname@example.org