WITH salinity being a significant barrier to productive farming in the area, the Wagin Woodanilling Landcare Zone (WWLZ) has been looking for methods to mitigate the problem.
With support from the South West Catchments Council and funding from the Australian Government’s National Landcare Program, WWLZ has been able to fund a three-year trial east of Katanning, looking at cow manure as a compost product to improve perennial pasture production on salt affected areas.
Paul and Lynley Keley’s property includes low-lying areas which form part of a watercourse feeding into the Coblinine River.
These areas have been degrading over the years and the Keleys were keen to try something new to improve the pasture potential on the site.
Oil mallees and saltbush had previously been planted in rows on the site, but there were still large areas going to samphire with very little pasture production.
This trial involved spreading varying amounts of cow manure across large plots followed by sowing in a salt tolerant perennial pasture mix.
Cow manure from a feedlot in Narrogin was transported to the property and spread at rates of 10 tonnes per hectare, 20t/ha and 30t/ha.
These, along with a control site and one with no manure and only perennials sown, made up the trial over an area of 22 hectares.
Soil tests were taken prior to works for comparison after the three years.
After an establishment period, grazing was conducted over the site to compare its production to previous years.
Ms Keley indicated that they were able to run sheep on the site for a noticeably longer period than before.
Photo monitoring using pasture cages was conducted throughout the seasons to determine what growth each amount of manure was generating and soil tests were taken in late 2016 to determine changes to the soil.
A fantastic result at the time of soil testing was the presence of micro-organisms including earth worms in the 20t and 30t plots.
The Keleys said there had not been anything at all present in that soil for many years, which indicated that the manuring at these rates created a suitable habitat for soil organisms, where perhaps the 10t/ha rate doesn’t generate as much organic matter.
Results from the soil tests showed some slight differences between the 20t and 30t plot levels, but on the whole they performed similarly.
These two plots did outperform the 10t plot on visual inspection, but the soil tests show that even the 10t plot had a reasonable impact on soil readings, however there were no micro-organisms visible when soil samples were collected.
The biggest setback to implementing this across a paddock scale would be the transport costs to get the manure on site.
To get best value for money WWLZ would recommend the 20t/ha rate as the most effective in a similar site to this trial.
More information: contact Gen Harvey at WWLZ on 9861 2222.