Pasture seed sown, job done? Not yet!

Pasture seed sown, job done? Not yet!

27 February 2021

You’ve sprayed out your paddocks and sown seed for new pasture – now it’s just a matter of sitting back and waiting for the grass to grow. Or is it?

Chances are, grass and clover aren’t the only seeds in the soil of your renewed paddock, and those other seeds are about to cause a potentially serious problem.

“The sprays we use before sowing do a great job of cleaning up the weeds that are already growing, but they have no effect on weed seed hidden in the soil,” Nufarm Territory Manager Chris Brenan explains.

“As soon as conditions are right for germination, those weeds will get growing as fast as your grass and clover, if not faster.”

Because of this, most new pastures need spraying after they have emerged, even though paddocks are sprayed before sowing.

“The moment you have weed seedlings in there challenging the clover and grass, you have competition for light, space, moisture and nutrients.

“That’s why part of your new pasture never becomes new pasture – it becomes weeds instead.”

Nufarm research1 comparing actual plants present in sprayed vs unsprayed new pastures shows how significantly early weed pressure can affect pasture composition, Chris says.

At 20 weeks after treatment, pastures not sprayed for broadleaf weeds in early establishment yielded close to 3,000 kilograms of dry matter per hectare (kg DM/ha), including 518kg/ha of weeds (mostly thistles) and 480kg/ha clover.

Plots sprayed for weeds had a very different result – just over 3000kg DM/ha total, with 175kg/ha of weeds and 650-780kg/ha clover.

In 25 years as upper North Island Territory Manager for Nufarm, Chris has seen more new grass paddocks than most. He sees spraying before the first grazing as the gold standard, as this is when weed competition does the most damage.

Tribal® Gold is the Rolls-Royce treatment at this timing. It’s ideal where farmers want a broader weed spectrum and/or need to control hard to kill weeds like chickweed, shepherd’s purse and buttercup.

Thistrol® Plus has a narrower weed spectrum and is also very effective before the first full grazing. If required, add Valdo® 800WG to extend the range of weeds controlled.

Dictate® 480 can also be useful for early weed control in new pastures and is more effective on weeds like storksbill, chamomile and stinking mayweed.

Different chemistry is required to kill weeds in new pasture after the first full grazing, and in this case, Baton® 800WSG herbicide is highly effective.

It’s important not to confuse the ‘first full grazing’ with the light pasture nip off recommended about six weeks after sowing. Young clover leaves, in particular, must be adequately grazed before Baton 800WSG is applied to minimise the risk of clover damage.

If necessary, Baton 800WSG can be mixed with Valdo 800WG to kill weeds that don’t respond to phenoxy herbicides, such as perennial buttercup and chickweed. In all situations, Chris advises keeping a close watch on those new paddocks!

“It’s easy to see a green strike and assume it’s grass and clover, when, in fact, there might be several other things growing there you really don’t want.”

For more information, talk to your local Farm Source Technical Sales Rep.

1 Nufarm Trial NUNZ0410: Effect of Baton on Drymatter Production and Clover Content of New Pasture.

® Tribal, Valdo, Thistle and Dictate are all registered products of Nufarm Limited. ® Baton Nufarm Australia Limited.

Article supplied by Nufarm.