Subsurface drainage keeps farm on top

By Rick Bayne

FARMING SUCCESS all starts underground for Cooriemungle’s Andy Powell.

His farm, just 15 km inland from the iconic Port Campbell National Park, receives about 750 mm of rain every year but, with subsurface drainage covering 98 per cent of the land, he’s strong on controlling the wet soil as part of a stringent pasture management program.

“Subsurface drainage is one of the management tools — it doesn’t solve wet pastures; you’ve still got to manage it, but it has transformed how we can farm the land,” Andy said.

“We can drive a tractor on the farm 365 days of the year and 24 hours after a rain event we can get on the paddock and spread fertiliser.”

Andy’s dad Ross started the subsurface drainage system about 25 years ago and quickly realised the benefits and spread it across the farm.

They have interceptor drains in the gullies and re-mole about 25 per cent of their paddocks each year, creating a shaft in the heavy clay soil to remove further water.

The farm has three main dams and is completely rainfall reliant with no irrigation.

“The drainage allows us to push up our stocking rates to get more out of the land, plus we get the benefits of less sick and lame cows and better soil health,” Andy said.

The pastures are old — most of them sown before 30-year-old Andy was on the scene — but they continue to perform with yields of more than eight tonnes a year.

Andy spends about three hours every week scoring every paddock, and makes sure they are grazed and stimulated.

“We monitor growth rates to get the best utilisation,” he said.

“A lot of farmers are good at growing grass but because of the wet soils they can’t utilise it. With the drainage we can utilise it and not damage pastures. It all comes back to monitoring, recording and analysing. Our Excel spreadsheets make it easy.”

In spring they keep post-grazing residuals at 1650 to 1750 kg dry matter. If the pasture gets outside this range they take paddocks out for silage and have shortened the rotation down to as little as 12 days. They aim to cut as much silage as possible to reduce risk.

“If we have a bad year we’ve got the silage. That bad drought a few years ago we were able to sell silage to farms in the district because we had excess feed,” Andy said.

Because of the good drainage system they are able start silage very early, which allows an extra couple of cuts. — Rick Bayne