Disease suppression: it's spreading!
GroundCover™ Issue: 22
In February, 300 farmers from four states attended a special farming conference in Dimboola, Victoria, presented by the Wimmera Conservation Farming Association and the GRDC. Denys Slee reports on some highlights from the presentations made over two days.
Disease suppression: it's spreading!
CSIRO scientists reported that in an intensive cropping long-term trial, stubble retention resulted in suppression of the soil-borne diseases take-all and Rhizoctonia.
They believe this is associated with increased turnover of soil organic matter from stubble retention and increased soil microbial activity (see Ground Cover report issue 10 "Natural control of Rhizoctonia...").
CSIRO Land and Water scientist David Roget now says that this phenomenon is not confined to the trial site in SA.
He said researchers last year inspected eight farms in SA and Victoria, which had a history of intensive cropping and stubble retention.
"While not all paddocks respond in the same way, effective levels of disease suppression can be detected where more intensive cropping and stubble retention have been practised.
"At this stage disease suppression has been detected only in relation to fungal pathogens. No effect of suppression on nematodes has been noted."
Nigel Wilhelm of the CRC for Soil and Land Management (CRCSLM) told assembled farmers that there are now many tools available to graingrowers to get their crop nutrition right. Like the following examples.
- Top 10 cm soil testing — commercial tests are available for estimating P and K levels available to crops and pastures. Most of these provide organic matter levels and acidity.
- Soil testing to 60 cm — a useful test in estimating N reserves, particularly in high rainfall districts.
- Sodicity — a package developed by the CRCSLM helps growers identify whether sodicity, acidity or salinity problems in the soil are affecting crop performance. (See coupon p18.)
- Plant testing — being used to measure the nutrient status of growing crops.
- Seed testing — grain can now be tested for its nutrient composition — important because plump seed with high nutrient levels will produce large vigorous seedlings.
"Any tests which identify production constraints can be useful in balancing a nutrient program," Dr Wilhelm said.
"Accurate herbicide histories can identify potential herbicide interactions which can impair crop nutrition. There are soil tests for estimating root pathogen loads and seed tests to detect seed-borne diseases."
"Information will be the most powerful tool for farming families in the years ahead. Treat it like soil, water, labour and money — it will provide handsome rewards," Bendigo (Vic.) consultant Neil Clark.
"There are large populations of microorganisms in soils. In a fertile soil, there may be more than 2 t/ha of them in the top 10 cm of soil," Margaret Roper, CSIRO Centre of Mediterranean Agricultural Research, Wembley, WA.
"In 1997 Nufarm commissioned consultants in SA and WA to review the trials conducted over the previous 10 years to determine what new information had been generated on trifuralin. This proved to be a rather mammoth task with the WA consultant locating more than 300 trials that included trifuralin,"Peter Howat, Nufarm Ltd.
"What was the previous crop is probably this year's weed," Mathew Sparke, IAMA, Horsham
Harvester with 3 moving parts
Ian Ridgway, Wolseley (SA) farmer and inventor, says he started thinking about it in 1954. In 1974 he started designing it, and now here it is.
'It' is the Ridgway Pneuflo, a revolutionary small plot harvester with just three moving parts and no external belts or chains — an invention which has been greeted with enthusiasm by plant breeders.
In a major departure from existing harvesting equipment the Ridgway Pneuflo, developed with support from the GRDC and Adelaide University and built by Irvine Engineering at Tintinara, uses a Shellbourne Reynolds stripping shaft with eight rows of arrowhead fingers which 'pluck' the grain from the heads.
This grain is then blown up into a rotary thresher where it is given a hand-like rub, and presto! — naked grain and chaff fall into an updraught of air which removes the chaff but lets the grain drop into the receiving tank.
It is claimed to be cheaper than existing plot harvesters, self-cleaning and light. It is also able to reap crops from almost at ground level to the taller, more erect types. And with a capacity of about 150 plots an hour it is no slouch in the speed stakes.
Growers might be cheered to hear that Mr Ridgeway is now working on how it can be adapted to a commercial harvester.