Grains Research and Development

Date: 01.09.2005

Software tracks ryegrass build-up

Resistant ryegrass is not a big problem for the members of the Lismore cropping group in the Western District of Victoria, and they aim to keep it that way. The GRDC award-winning TOPCROP group"s members are using a computer program to track the impact of their rotations on the development of annual ryegrass.

Most members of the group moved to no-till or minimum-till practices about 10 years ago, and in the past five years they have begun moving their farming operations to raised beds. One of the members, Chris Lang, is trialling a program called RIM (ryegrass integrated management). Developed by the University of Western Australia and the West Australian Department of Agriculture with GRDC support, the system, he says, has thrown up some warning signals.

"One of the features of the program is an estimate of how many treatments of group A and B herbicides and glyphosate you have left before you risk developing ryegrass herbicide resistance," Mr Lang says. "Some of us have very few options left.

"The program takes account of such things as the impact of cultivation, herbicide treatments, grazing, hay cuts, crop prices and sheep returns and predicts the impact of the treatments on ryegrass counts and gross margins."

Mr Lang says that grazing forms part of the farming mix of most of the members and that while annual ryegrass can supply a significant bulk of fodder in a pasture situation, "you really don"t know how much you have until you move into a cropping phase, and then it"s a real menace and its grazing value won"t compensate for the crop yield loss".

Mr Lang has used a combination of spray-topping, heavy grazing and haycutting during the pasture cycle to control ryegrass and is happy that he has ryegrass numbers "right down". He uses the winter wheat varieties More and MackellarA to provide winter gazing and says that because of withholding periods, it is important to go into these crops free of grass weeds.

"My usual practice is to graze 2000 sheep on 40 hectares of winter wheat for a week, spell the paddock for three weeks and then repeat the process. I find that I can get three very valuable grazings between May and August each year and that stubble also provides valuable grazing."

The Lismore group began life as a typical TOPCROP group 10 years ago. In the past it has run state-focus trials with wheat and pulse varieties, and this year several members will be trialling the timing of nitrogen application.

While the members are very professional, long-term croppers, there is a range of interests and experience across the group. This makes benchmarking difficult, but all members take part in lively discussion for the exchange of practical information.

The RIM program was the subject of an afternoon training session, with a couple of members of the group taking it up and others watching over the fence.

GRDC Research Code DAV00045
For more information: Chris Lang, 03 5596 2014, vlang@ansonic.com.au

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