Getting deep with subsoil manuring

That was the message from a talk at a Southern Farming Systems (SFS) field day at Hamilton, Victoria, last week.

The Venning family, west of Hamilton, has experimented with a trial block of subsoil manuring, using material from a feedlot down the road at Coleraine.

Todd Venning said while it was a slow process to get the paddock prepared as the family was moving so much material, so far it looked like the process was paying dividends.

Also speaking at the day was one of the pioneers of broadacre subsoil manuring, John Sheehan, Yaloak Station, near Ballan.

Mr Sheehan said the process of subsoil manuring had definitely worked for him and that he was trying to do more acres, but added that farmers may shy away from both the time consuming nature of the incorporation process and the price.

“The price can be well over $1000 a hectare, so you’re nearly buying your ground back again, but we believe the return on investment is there.”

Mr Sheehan said on the sodic soils in his area there had been spectacular results, especially in canola.

“The results have always been better than the untreated section of the paddock, but sometimes you get a really good result.

“We had canola last year that went 4.4 tonnes a hectare on the treated section, compared to 2.7 tonnes a hectare on the untreated, if you get those sort of returns, then it pays for itself very quickly, even at the high cost of getting the manure out there.”

Mr Sheehan said the best results came with chicken manure, which he can source locally, but said there were problems with that.

“There is only a limited amount of chicken manure around and it will only suit those within a reasonable distance as the freight gets too much otherwise, so we’re going to have to find another source to put down into the soil.”

He said some work was being done with crop residues, but they would not have the fertility of the manures.

SFS research officer Corinne Celestina agreed.

“Certainly, chicken manure seems to have that sweet spot in terms of fertility and organic matter.”

However, Mr Sheehan said he would continue to work with materials more widely available for farmers into the future, such as crop residues, to try and get a good formula from that product.

Subsoil manuring encourages deeper root development through incorporation of high rates of organic matter into the upper layers of clay subsoils.

Mr Sheehan said it had a particular fit on the sodic soils of the State's western district.

“We can be waterlogged early on, and then it sets hard and the crops can end up having moisture stress, even though there is moisture at depth as the crop can’t push through the hard pan.”

He said he believed subsoil manuring was the best way of renovating the heavy clays of the area.

“Deep ripping gives a temporary response but nothing permanent.”

According to Mr Sheehan, good gains could be made by streamlining the application process.

“We’ve been working on something at Yaloak that will allow us to get the manure out a bit quicker.”

At present, application rates are slower than a hectare an hour.

“You’re moving a lot of manure so it can be pretty slow,” Mr Venning said about his experience at Hamilton this summer and autumn.