SWATHING barley has been an important means of preventing head loss in Gairdner barley on the south coast this season.
But swathing introduces the risk of sand contamination that would send loads to the feed stack.
Early survey results from the Fitzgerald Biosphere Group trials coordinator Nigel Metz indicate swathing can be a double-edged sword for south coast growers.
"With wind and rain over the past few weeks, head loss has been a problem in Gairdner barley because it produces a heavy head," Nigel said.
"But the swath formation is important and central delivery swathers tend to make a better swath row.
"Some farmers have been burnt badly in the past and there are a number who are hedging their bets either way, swathing some and direct heading the balance."
Esperance and Albany port zones account for 70pc of the state's barley receivals.
But in seven out of 10 years the region faces difficult harvest conditions, according to Co-operative Bulk Handling crop production specialist Peter Nelson.
CBH claims sand and stone contamination in grain crops was the bulk handler's biggest problem at south coastal receival centres last year.
The contamination problem was accentuated by the dry season and caused by sand splash and short crops.
Mr Nelson said the problem was detecting the sand in samples, because it sinks to the bottom of the load.
"But it ultimately ends up in the stack and the delivery is downgraded to feed," he said.
"We do not have the cleaning infrastructure to deal with it."
An 18ha plot of Gairdner barley was the focus of a trial this year involving Fitzgerald Biosphere Group members Brian and Julie Keding at Gairdner.
The swathing trial will attempt to give some direction on timing, the lay of the swath, swath height and equipment for harvesting and collection.
With input from CBH and the Agriculture Department, eight treatments were applied to the 5t/ha crop, the swath cut generally at one day intervals and moisture levels ranging from 41pc to 15pc and a comparison drawn with the direct harvested barley.
Swaths were monitored for colour, protein, screenings, insect numbers, germinability, temperature, moisture and quality.
Department of Agriculture entomologists based at Albany monitored ground dwelling beetles in the swath throughout the trial.
The swath was picked up after about 10 days, when moisture levels were 10.5pc.
There were some extreme 42C day temperatures last month during swathing and temperatures of 55C were recorded on top of the swath and 45C beneath the swath.
According to Mr Nelson, the yield of the barley that was swathed at 40pc moisture was slightly less than the rest of the trial swathed at lower moisture levels that yielded 5t/ha.
Rain has been intermittent this harvest and none of the swathed barley has made malting grade because of grain colour.
Mr Nelson said it was possible to swath barley at 30pc moisture, when grain had reached physiological maturity.
"Swathing can reduce the risk of head loss and army worm infestation, as well as extending the harvesting period," he said.
"But if you drop the swath today and get 50mm of rain tomorrow, the swath will be forced through the stubble and you run the risk of contamination with sand.
"In a light rain, only the top of the swath is harmed, but if the rain is heavier, a standing crop will dry quicker than a swath and there is probably a greater chance of sprouting in the swath, following a downpour."
Mr Nelson questioned the rationale behind swathing barley at 16pc moisture, perhaps two days before it could otherwise be harvested direct.
Weighing up the risks associated with swathing, he said direct harvesting at
20pc to 22pc moisture and then aerating the barley and drying to 13.5pc moisture, when time permitted, would be the ideal situation, eliminating the need for swathing.
CBH supply chain manager David Fienberg said the bulk handler has 1 million tonnes of aerated storage at the Albany and Esperance receival centres.
"We are stretching the boundaries on grain moisture at Esperance, with a trial in one 8000t bulkhead where we have accepted barley up to 15pc moisture," Mr Fienberg said.
"Malting barley quality is absolutely dependent on moisture content and storage temperature and the risk of mould is heightened under high moisture conditions.
"To make the malt grade, grain must fall within a 98-100pc germinability range, and the key to extending storagability is reducing grain temperature to about 15C, which is achieved via aeration."
Fitzgerald Biosphere Group trials officer Nigel Metz is co-ordinating a survey of south coast growers to compile a booklet that will serve as a swathing guide, detailing best practice.
Information will be presented at Crop Updates and throughout 2004.