SALINITY is seen more as an opportunity than a ‘cancer’ by John Nicholls, whose Doodlakine property is in an area of Western Australia that’s been affected for decades.
Over recent years he’s been planting saltbush and oil mallees to help reduce the watertable and diversify his income, but that hasn’t stopped salt crystals forming on his paddocks.
As Chair of the Wallatin Wildlife and Landcare Group, Mr Nicholls has seen some very effective deep drainage systems, and thought it might be an effective solution.
To determine whether a drain would work on his own property, Mr Nicholls used a system called DrainLogic, which was developed by the Department of Agriculture and Food (DAFWA) with funding from the Grains Research and Development Corporation (GRDC).
“People around here have been living with salinity all their lives, so it’s not as big as issue as some other areas where it’s developed recently,” Mr Nicholls said.
“About 10 percent of my property’s salt affected, so I can’t crop it and it’s only useful for grazing when there’s been enough winter rain.
“However, this paddock hasn’t been affected enough to have salt crystals form on the surface until the past few years. I thought the water table was rising, which is why deep drainage seemed to be the solution,” Mr Nicholls said.
He runs a family partnership with brother Peter and Mum Lalla. The enterprise is highly diverse, although cropping is the main income stream.
Running sheep allows weed control through grazing hotspots; feedlotting lambs and a small intensive piggery use any off-spec grain; and a few cows provide the Nicholls family and some neighbours with home grown beef.
Over recent years Mr Nicholls has also planted 110,000 saltbushes and a similar number of oil mallees, which will eventually provide a containment area for lambing, with good weather protection and plenty of feed for the ewes.
“The aim of the deep drainage was to stop water getting to the area and into the watertable. The plan was to put an 800 metre long drain alongside the shire road where I noticed the salt crystals appearing on both sides of the bitumen,” Mr Nicholls said.
“I know how important it is to research your options, so I got a guy from DAFWA out to talk through the DrainLogic process. It only took a couple of hours, and was well worth it.
“You need to know some basic information up front, like your soil type, so I had the area surveyed before the meeting. But if there’s something you’re not sure of, the process lets you go and find out and then come back to it.”
One of the DAFWA scientists behind DrainLogic, Richard George, says the program is not a replacement for having an engineering assessment of your property, but it can help you work out what to look for in that process.
“It’s a conversation starter, encouraging farmers to look at their soil type and permeability, drainage designs and other options for selecting parts of paddocks to drain and how much land might be recovered.
“It helps farmers think about where drains may work best and the impact drainage might have on yield and returns versus costs. It also prompts questions about legal and downstream issues, especially when you can be shifting large flows of saline or acidic water.
“You’re looking at an up-front cost of anywhere from $10,000 to $100,000 for planning and construction, so you want to make sure there is value in digging and maintaining drains,” Dr George said.
In the end, working through DrainLogic, John Nicholls came to the conclusion that deep drainage was not the best solution, at least for now.
“It encouraged me to put in a couple of observation pits two metres deep - the depth I was planning to construct the drain. If it was going to work, they would have filled with water very quickly. A couple of weeks later, they were still dry,” Mr Nicholls said.
“It’s a win-win, because I learned more about what’s going on with my land and about deep drainage, and saved money, even though I haven’t fixed the problem.
“That’s not to say it won’t be part of the answer down the track, particularly if we have a few wet seasons. I’ll keep monitoring that patch of land and maybe go through the process again if things seem to change.
“I think it’s great to have such a simple checklist available for farmers looking for solutions to salinity, so they can work through deep drainage as one of their options,” Mr Nicholls said.
DrainLogic and other information about salinity management is available in the ‘environment’ section of the DAFWA website, www.agric.wa.gov.au.
Another resource, Helping Grain Growers Manage Dryland Salinity, is available to download free of charge from the GRDC website, www.grdc.com.au.
Released in 2009, the report outlines two GRDC supported projects aimed at understanding the processes driving salinity and assessing the likely effectiveness and financial costs and benefits of potential management options.
One project was based in the Wallatin–O’Brien catchments in the WA wheatbelt east of Perth (where some of the examples in DrainLogic were derived), the other in the New South Wales Riverina.
