Push for less ploughing and more herbicides

22:38, Feb 21 2013
Nick Poole
Foundation for Arable Research director of research and extension Nick Poole talks about the benefits of reduced tillage at the South Otago/Southland Field Day last week. 

Southland crop farmers can save time and money if they reduce traditional cultivation techniques such as ploughing, industry experts say.

Traditionally, farmers intensively ploughed the land, also known as tillage, to grow new crops and control weeds by overturning and burying them.

The Foundation for Arable Research (FAR) held its annual South Otago/Southland Field Day last week. Representatives pushed the benefits of reduced tillage and the use of herbicides to control weeds, rather than through intensive ploughing.

About 50 farmers and industry leaders gathered at a crop farm in Clinton to look at different methods of cultivation and its impact on soil quality and crop yields.

FAR director of research and extension, Nick Poole, said there was a trend towards using reduced tillage techniques in New Zealand.

"We [New Zealand] have moved the goalpost towards minimum and no-till.


"We've heard from growers who have moved to minimum till and say they wouldn't go back," Mr Poole said.

Reduced tillage improved productivity, because farmers did not use ploughing machinery as much and saved on labour costs, he said. Soil quality improved after less ploughing, which benefited the environment as less nitrate filterered through to the ground.

When farmers plough less and manage grassweeds through the use of herbicides, it is faster to work between each crop, shortening intercrop times and increasing productivity.

A disadvantage of less ploughing and rotation of soil means there could be more grassweeds, because they are not getting buried.

With that in mind, it was important to control grassweeds through cultural and agrichemical control, he said.

There are new agrichemical options in the pipeline to help manage reduced tillage techniques.

A recently released new herbicide in Australia for grassweed control is expected to be available on the New Zealand market in 2014.

It featured in FAR's herbicide screening trial for two seasons and was expected be a "game changer", he said.

Some cultural control methods such as break crops, spring cropping, rotational stubble burning and rotational ploughing helped to combat grassweed build up, he said.

Plant and Food Research senior soil scientist Trish Fraser said reduced tillage was one way to help maintain high-quality soil and encourage crop growth.

High-quality soil had plenty of nutrients, aeration, water, organisms and good structure, and reduced tillage helped protect the soil and maintain good root systems, she said.

"If you've got a good structure, you'll get better yields.

"It's a bit of a balancing act, because you can easily destroy it by too much trafficking," she said.

Farmers can also protect their soil by growing cover crops, retaining crop residues, avoiding over-grazing and reducing equipment or livestock traffic on wet soils.

Kelso Kontracting owner Athol Lawlor said the capital costs of minimum and no tillage techniques were high, and there was no silver bullet.

There would be machinery and chemical costs, and it seemed as though it could be promoted by chemical companies, he said.

FAR chief executive, Nick Pyke, said the costs involved should be treated as a capital investment.

The Southland Times