The competition is open to students from years Prep to 12. Activities will include a weed seed bank experiment, a weeds survey, and creating a weed herbarium.

Other tasks offered under the theme "What makes a weed a weed?" include designing a weed-themed trumps card game, preparing a scientific poster or video presentation and creating a new weed from plant parts.

The competition, now in its 16th year, opened 23 January with a number of schools from Queensland, New South Wales, Victoria and Western Australia already registered. The competition closes on 18 May 2012.

DEEDI competition organiser Kerrie Rubie said competition activities had been linked to the new Australian schools' curriculum to make it easy for teachers to incorporate the competition into their learning programs.

"It also fits well with the Primary Connections Plants in Action unit 'Life and Living', a program that enhances teaching and learning in science and literacy," Ms Rubie said.

Competition sponsors have donated many great prizes, including a part scholarship to the value of $1,000, a 12-month subscription to a scientific journal plus a range of medallions, trophies, science-based educational materials and certificates.

Winning entrants may also be eligible to enter their weeds project in the National BHP Billiton Science Awards.

Ms Rubie said the competition was popular with teachers and students who enjoyed the required observation, recording and practical activities.

"This annual event has helped more than 60,000 students from around Australia to increase their knowledge of agriculture and crop science," she said.

"It has shown students the way forward in possible careers in science and primary industries.

"The main goal of our plant science competition is to stimulate an interest of science and agriculture in young people and to express to children that science is a great, long-term, rewarding career choice."

To enter the 2012 Plant Science Competition contact Kerrie Rubie on (07) 4660 3666 or email kerrie.rubie@deedi.qld.gov.au

< p>Sponsors are the Grains Research and Development Corporation (GRDC), the Paul Johnston Memorial Trust, the University of Queensland, Education Queensland, Pioneer Seeds, Grains Research Foundation Ltd, the Australian Institute of Agricultural Science and Technology, Blue Ribbon Seed and Pulse Exporters, HSR Seeds, Professor and Mrs Joe Baker, Selected Seeds and Warwick Art Gallery.