There is no doubt that increasing the crop seeding rate is an effective tool for suppressing weeds in the absence of effective herbicides, Roger Cousens, of the University of Melbourne, told farmers at the NSW Cropping Updates supported by growers and the Federal Government through the GRDC.
"It will also often increase crop yields, either with weeds present or if there are no weeds at all; and few if any experiments, even in dry years, have showr reductions in grain yields or increases in screenings from doubling current seeding rates," he said.
"There is clearly a cost involved. Doubling the seeding rate might cost a further $10/ha in seed, plus there will be double the number of stops to refill combines, and a cost of storing more seed on farms.
"However, both farmers and advisers tend to dismiss the seeding-rate option out of hand. Is it just cost, or is it the aversion to risk — unsubstantiated in experiments — that crops risk running out of water?"
Professor Cousens posed the question: is there any point in researchers further pursuing this option of weed suppression, at least until more weeds become resistant to herbicides?
Contact: Professor Roger Cousens 03 9344 7390