"We're trying to maximise the effectiveness of lupin establishment in areas that are not high risk for root rot. We want to get as many plants as possible for seeds that we sow," said agronomist Rob Delane
Mr Delane, at the Geraldton District Office of the Western Australian Department of Agriculture, is part of a GRDC-funded investigation into lupin establishment in the northern wheatbelt of Western Australia.
The project has produced important guidelines for sowing.
Major factors are uniform depth control of 3-5 cm and a seeding rate high enough to achieve at least 45 plants/m2. This requires a knowledge of the germination test value of the seed and an allowance for seedling death.
Grower Warwick Speechly of Eradu considers himself lucky to have come through the last season relatively unscathed while many neighbouring growers suffered poor yields. But Mr Speechly, who has 1500 hectares under lupins, is also adapting advice from the Department to suit his needs.
He said he's traded in his cultitrash for tines to get the recommended seeding depth of around 5cm. "It seems to be working," he said of this first season under the new strategy. Mr Speechly has also gone to press wheels to keep the seeding machine moving at a constant depth.
Stubble retention critical
Researchers have recommended stubble retention to avoid wind damage and brown leaf spot. They say generally sowing into cereal stubble is better than sowing into pasture. Weed control can be poor when sowing into pasture and some seedling diseases more severe. However there are problems associated with the technique.
"Tines have problems getting through stubble," said Mr Speechly. "I may have to put on a disk coulter to try and cut through the stubble. It may be expensive to get through some of these problems but I'll have to do it."
"We still haven't conquered efficient seed placement in heavy stubble," said John Hutchinson who farms lupins in South Mingenew. "We're getting better results on our place sowing lupin into pasture, certainly in areas prone to brown leaf spot."
A related research project (see story Best Bets this page) has concluded that wide spacing of rows goes a long way towards overcoming the stubble seeding problem without sacrificing yield.
Seeding and the ideal seeding machine
Suitable seeding conditions are important, particularly for April to mid-May sowings. It is better to sow into wet or dry soil than into a rapidly drying soil, where staggered germinations, difficult weed control and high seedling mortality occur.
"It's not a matter of a single optimal system. We've developed criteria for farmers to adapt depending on soil types different moisture conditions, stubble level, disease loads and the seeding machine," said Mr Delane.
He said an ideal seeding machine would sow seeds at an accurate depth, handles high stubble levels, incorporates pre-emergent herbicide evenly, mechanically kills weeds and ensures good seed-soil contact.
As it is, growers have the option of modifying existing machinery such as the cultitrash to improve seed placement, buying new machinery or lobbying for a new machine to be developed.
A useful leaflet pulling together the current state of research information h; been compiled by Mr Delane and his colleague Peter Nelson. It's called Producing Lupins in Western Australia and can be obtained from the Department.