Ground Cover South : Ground Cover 051 August-September 2004 - South
NEWS/RESEARCH UPDATES 8 AUGUST 2004 By EMMA LEONARD Hands up anyone who has heard of granivory and its role in reducing herbicide resistant weeds? Well, granivory, the eating of seeds by insects and small mammals, could become an important new ally for growers battling herbicide resistance. Granivory already plays an important role in regulating plant populations in natural ecosystems, which is what led Department of Agriculture WA researcher David Minkey to look at the role that granivory might already play in the management of herbicide resistant ryegrass and wild radish. In short, he found it has a significant role, especially in lighter soils. Further, he has found that modifications to crop management, such as no-till or even spraying molasses on stubble, could help increase gravinory. Mr Minkey's research -- the first of its kind in Australia -- together with colleagues Helen Spafford Jacob (UWA), Jonathon Majer (Curtin University) and Catherine Borger (UWA), has looked at granivory under no-till conditions in a range of soil types and under various rotations. Several species are involved in granivory in cropping paddocks. At the perimeter, mice, rabbits and birds all play a part; however, the team found that ants are the main players in weed seed removal right across the paddock. Much of his work was in a 16-hectare cropping paddock at Merredin, WA. Here he found and mapped the distributions of 32 species of ants. Several of these were major seed consumers. For example, the tiny Monomorium rothsteini, the most abundant species in this paddock, are particularly partial to the tiny seeds of ryegrass. Mr Minkey reports that seed removal is patchy across a paddock and can vary between 0 to 100 percent. On average, in his sample paddock, 80 percent of all ryegrass seed was removed and 40 percent of all wild radish. Wild radish seed collection fell under canola stubbles due to a decline in seed eating ants, although ryegrass seed removal was the same under canola, lupin and cereal stubbles. This could be due to the isothiocyanates released by decomposing canola roots which are known to have a fumigator effect in the soil. No difference was found in the level of granivory from normal winter/spring applied herbicides and insecticides. Ants are less active on the soil surface during these periods and so have less contact with chemicals. Tillage appears to be a double-edged sword for ant populations. Multiple pass operations result in fewer ants as colonies are continuously disturbed. However, one-off tillage events, as experienced in no-till seeding systems, seem to encourage opportunistic seed eaters but discourage other species. For example, Mr Minkey's work shows that populations of the large meat ant (Iridomyrmex greensladei), which are not a major granivory species and indeed repel more important weed eating species, tend to decline following any form of soil disturbance. GRDC RESEARCH CODE DAW 492, program 3 For more information: David Minkey, 086488 7980, email@example.com Ant recruits for weed fight Making a withdrawal: Ants consume large numbers of weeds seeds and have been found to play an important part in reducing the weed seed bank. NSW Department of Primary Industries (DPI) staff involved in the National Soybean Breeding Program have launched a push to encourage more farmers to grow soybeans as a food crop for people. Mostly grown in Australia as a 'break' crop, using no-till cultivation, soybeans have been used to recycle nitrogen and improve sustainability of a farmer's principal crop. However, NSW DPI's program leader for Crop Improvement, John Sykes, says growers converting their variety choice areas to human food quality may capitalise on prevailing market conditions. He says Asian markets offer potential for exporting 'fresh' soybeans to niche markets. "The challenge for the industry in Australia is to revitalise grower interest in regions where soybeans are a preferred break crop, or where production for a niche market can be sustained." Soybeans are grown in Australia in three farming systems -- dominated by sugarcane, perennial pasture and rice. He says one of the most promising regions for growing soybeans for human consumption is the Murrumbidgee Irrigation Area, where water restrictions are providing opportunities for shorter growing season summer crops, other than rice. "Soybeans are not only profitable but also complementary to rice and other winter cropping rotations. "They help break disease cycles, improve soil structure and fertility, reduce weed seed-banks and improve total water-use efficiencies. "Following the soybean crop, a winter cereal is again no-tilled into the soybean stubble or residue. This means the crop can be sown on- time and the paddock cropped 52 weeks a year." Mr Sykes recently attended an international soybean conference in Brazil, where he said delegates outlined desirable quality standards identical to those already used in Australia's national breeding program. "Our emphasis is on new traits such as protein type (needed for firmer tofu), calcium content and freedom from lipoxygenase (which removes bitterness)." GRDC RESEARCH CODE CSP 338, program 2 For more information: John Sykes, 02 6881 1270, firstname.lastname@example.org Market conditions 'right' for soybeans WA researcher David Minkey: found and mapped the distributions of 32 species of ants in a cropping paddock. Career Opportunity Coretext Pty Ltd, which produces Ground Cover for the Grains Research and Development Corporation, is seeking to employ a suitably qualified and enthusiastic person to research, write and edit for the newspaper. The successful candidate will be tertiary qualified in an appropriate agricultural or science subject and have a keen understanding of and interest in the future of the grains industry and its people. Experience in journalism, particularly science or agricultural writing, will be an advantage, but consideration will also be given to training the right person. This is an excellent chance to join a fast-growing publishing company working in one of Australia's most strategic and important sectors. Opportunities will also arise to contribute to other Coretext publications. The position is Melbourne-based. In the first instance, please email a brief CV to the managing editor, Brad Collis, at email@example.com.
Ground Cover 052 October-November 2004 - South
Ground Cover 050 June-July 2004 - South