Ground Cover North : Ground Cover 049 April-May 2004 - North
RESEARCH UPDATE 12 APRIL 2004 Frost is an ever-present problem for graingrowers in southern NSW, and one which is diffcult to measure in terms of actual lost productivity. To try and measure the problem more accurately, and fnd possible management options, a temperature study was established as part of the GRDC- funded project ‘Tools to reduce the impact of climate variability in south-eastern Australia’ (involving NSW Agriculture and DPI Victoria). The study examined temperature variation across paddocks and how these temperatures compared with the nearest Bureau of Meteorology (BoM) station. If a comparison could be made, historical temperature data could be used to look at frost risk over time. Ten data loggers were placed in each of four paddocks at Junee Reefs, Burrumbuttock, Ardlethan and Rankins Springs. Elevations within the paddock ranged by 33 metres at Burrumbuttock to just 1.5m at Ardlethan. Temperatures were downloaded monthly from July to November 2003. Unfortunately, it was a really good year to do the monitoring – because there were severe late frosts. Temperatures varied markedly within paddocks according to elevation, soil type and cold air drainage. At Junee Reefs, minimum temperatures on 10 August varied in the paddock by 5oC from the coldest point (-7.8oC) to the warmest point (-2.7oC), over a change in elevation of 25m. The difference in fowering time between these two points was six days. A common result from the monitoring was that at three of the sites, the median difference in temperature between the coldest point in the paddock and the nearest BoM station, was three degrees (for frosts of at least -3.5oC in Sept/Oct). If we assume a signifcant paddock frost is -3oC (the temperature at which damage is likely to occur in wheat is -3.5oC), this would equate to 0oC recorded at the nearest BoM station. The number of times temperatures of 0oC or below have been recorded is very infrequent, suggesting 2003 was a very unkind anomaly. GRDC RESEARCH CODE DAV 00006, program 4 For more information: Kirrily Condon, 02 6978 0428; firstname.lastname@example.org NEWS IN BRIEF By EAMMON CONAGHAN The nation’s weeds assault has taken another turn for the worse with the arrival of a small-fowered mallow (Malva parvifora) – and it brings with it a natural resistance to glyphosate herbicides. You may not have heard of the small-fowered mallow because it is relatively new to these parts, but University of Western Australia researcher Professor Julie Plummer suspects it will soon be a household name. “Small-fowered mallow can produce 5000 seeds per plant and the resultant progeny mature very quickly, which means populations can explode. Being capable of ‘in-breeding’ also means that only one plant is required to begin a new colony.” During the 1980s in Canada, a close relative of M.parvifora doubled its population in fve years to spread through wheat crops and slug growers with 30 percent yield penalties. To prevent similar problems with M.parvifora in WA, the GRDC has supported UWA PhD student Pippa Michael to study the pest and inform management strategies. One of the frst stops for a scientist investigating control of resistant weeds is the livestock option – where animals are used to graze seeds that, in theory, lose their viability after digestion and so fail to germinate. Ms Michael therefore studied the behaviour of M.parvifora seeds in the sheep rumen. Already, she knew that they passed straight through monogastric animals such as horses at a rate of up to 700 seeds per day. What she hoped was that the micro-organisms unique to ruminants, which can break down stubborn carbohydrates such as cellulose and cellobiose, would also infltrate the tough coat of M.parvifora and destroy the seed. There was bad news and good. “When hard seeds with intact seed-coats were placed directly in the rumen, 93 percent remained viable after 48 hours,” she reports. “But while dormancy was not broken by enzymatic digestion alone, the combination of mastication through chewing and exposure to the rumen may offer some promise, with 98 percent of previously damaged seeds losing viability after 12 hours in the rumen. “If chewing provides the seed coat lesions necessary to encourage rumen break-down of M.parvifora seed viability, it could become a key method of control.” On the other hand, if chewing does not infict the necessary seed coat damage, grazing sheep will simply act as a taxi to distribute the seed further and aid the spread of the pest. Research will continue at UWA this year to gauge how well sheep damage the seed before delivering the prognosis on their utility as a control option for M.parvifora. GRDC RESEARCH CODE UWA 369, program 3 For more information: Pippa Michael, UWA, 08 9380 7980, email@example.com; Associate Professor Julie Plummer, UWA, 08 9380 1786, firstname.lastname@example.org Understanding frost risk by monitoring on-farm temperature By KIRRILY CONDON, manager – research & communication, FarmLink Research Study results Based on historical temperature records, the frequency of signifcant frost events is low in the areas studied. However when they do occur, as the study revealed, the impact is signifcant. Late sowing to delay fowering has been a common management option used to avoid damage from late frosts. However, optimum fowering time is a compromise between fowering too early and suffering yield loss from frost, or fowering late and suffering yield loss from heat stress and high evaporation. Based on the historical frequency of frost events, it is suggested that the number of years a yield advantage could be achieved by sowing early (in the optimum sowing window) would outweigh the number of years an advantage could be made by sowing late to avoid frost. As the severe frost events of 1998, 2001 and 2003 showed, sowing time had little infuence on the amount of damage. Management practices for high frost areas In frost-prone paddocks (or parts of paddocks) where the frequency is likely to be much higher, alternative crops and special management practices should be considered, including: n barley or oats – are able to tolerate lower temperatures than wheat; n grazing wheats – consider a grazing variety so that if a late frost reduces yield, the loss of income has been at least partially offset by the grazing beneft: grazing will also delay maturity by a few days which could avoid a particular frost event; n awnless wheats – make good quality hay if necessary; n varieties with a range of maturities – may help spread the risk in less severe, late frosts; and n short rotations – lucerne is not damaged by frost. Harsh mallow hard to digest Dealing with an unwelcome arrival: UWA PhD student Pippa Michael with M.parvifora. Campaign urges growers to report anything unusual A new awareness campaign has been launched by Plant Health Australia which urges growers to report any unusual pests or diseases in their crops. In the grains industry Karnal bunt – controversially used by Pakistan to reject an Australian wheat shipment – has been identifed as one such exotic disease of which graingrowers should be aware. Karnal bunt is not present in Australia, but if an incursion occurred the annual losses are estimated at $500 million a year, in the worst case scenario. A recent workshop established a national diagnostic standard for Karnal bunt, which is a fungus that infects wheat grains at fowering. The grain is partially or completely replaced with a black powder which smells like rotting fsh. These symptoms can be confused with common bunt and some other grain diseases, but PHA would prefer growers to be safe than sorry. If growers observe this or any other potentially exotic disease or pest, they are encouraged to call the Exotic Pest Hotline on 1800 084 881. Wee Waa student wins GRDC award for training Wee Waa’s Vanessa Cain has won the Northern Region GRDC Agricultural Training Award for 2004. Ms Cain intends using the $5000 award to continue her Diploma of Agriculture Course at Dalby Agricultural College. Now in her second year, Ms Cain is studying the ‘Integrated Pathway’, a general course encompassing cropping and livestock electives, before returning to the family farm, Wattle Vale, at Wee Waa: “The course will allow me to introduce new grains into our existing cropping rotation, as I wish to continue the predominantly grains-based income,” Ms Cain says. Storage research has big dollar beneft Graingrowers can expect a return of more than $20 for every $1 invested in storage research, according to chief of CSIRO Entomology, Dr Joanne Daly. Dr Daly says an independent cost-beneft analysis of CSIRO’s research into stored grain predicted an annual return of $87 million for the Australian grains industry. “The survival of the grains industry in Australia is still fundamentally linked to its relationship with the grain storage industry,” says Dr Daly. CSIRO recently signed a new Stored Grain Research Agreement worth $9.25 million over the next fve years. Global GM canola increases for seventh year in a row Global GM canola plantings increased in 2003 for the seventh consecutive year, and now make up 16 percent of the global canola crop. Area sown was up 20 percent, according to the International Service for the Acquisition of Agri-biotech Applications (ISAAA). “Farmers continue to rapidly adopt biotech crops because of signifcant agronomic, economic, environmental and social advantages,” ISAAA Chairman Clive James says. GRDC Western Region Panel chairman and Hyden grower Dale Baker says although the Offce of the Gene Technology Regulator had cleared GM canola crops for Australian release, state government moratoria may still limit the adoption of GM crops in Australia.
Ground Cover 050 June-July 2004 - North
Ground Cover 048 February-March 2004 - North