THERE are a number of trials that are tackling seeps on the Bond family farm at Ponde, near Mannum, but one involving summer cropping has resulted in some success.
Brothers Kevin and Geoff Bond, with co-workers Daryl and Brett Newman, no-till crop about 3400 hectares.
In the past decade though, they had started losing parts of their productive land to seep damage.
"The land goes from being the best you've got because of the perched water table to not being able to grow anything," Kevin said.
"Continuous cropping hasn't helped. It means we don't have the plants there in summer utilising the extra moisture so the water starts to run, particularly in non-wetting sands, and pools in a nearby area."
Following the wet 2016 season, they began working with Mallee Sustainable Farming and project manager Chris McDonough.
"We needed to figure out how stop that pooled water evaporating over summer and creating a capillary rise, which brings salt to the surface," Mr McDonough said.
So immediately after the wet 2016 season, the Bonds sowed a summer crop of sorghum and millet for the first time on an area of concern.
"We grew a mix to see which species could handle that seep-type environment the best," Kevin said.
They didn't harvest the crop in the first year as it didn't germinate well due to the wet conditions, so they sowed a winter cereal through it.
The next summer, they sowed the annual variety mix again after harvest.
This time the crop thrived, so the Bonds were forced to cut and bury it in the soil prior to the 2018 seeding.
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The seeds of that buried crop then germinated during the season so the Bonds cut the trial area for hay.
They didn't resow the summer crop in 2019, so were surprised but pleased to see it re-germinate on its own, albeit mildly, during the winter cropping season.
Geoff said where possible, they had avoided summer sprays, such as amine and glyphosate, to encourage the summer crop to regenerate, with only gramoxone used to crop-top for harvest.
"If we get good October rains, the mother plant did regenerate, but being our summer, it doesn't grow too big because the moisture really backs off," he said.
Kevin said that was the reason they usually could not grow summer crops, "because we just don't get the rain here".
But the summer crop grew mildly again this year, so the Bonds have sown wheat into it with minimal issues and relatively good germination.
They also don't expect to see another summer crop arise, as group B herbicides have been used in-crop.
"We had already been out to assess moisture levels in the soil profile and were surprised we couldn't find too much, so the summer crop had done its job," Kevin said.
They plan to harvest the grain this season.
I feel the summer crop made sure that salty excess moisture never came to the surface.
- CHRIS McDONOUGH
Mr McDonough also couldn't find a saturated layer beneath the site.
"I feel the summer crop made sure that salty excess moisture never came to the surface," he said.
"They wont have to ameliorate like that again until the next very wet season."
But while Mr McDonough was pleased with the reduction of the water discharge area, he said farmers also needed to address conditions at the recharge area where the problem starts.
"Whether it's sowing lucerne in non-wetting sands on hill slopes; spading in organic matter to fix soils; or clay spreading to reduce the amount of water flowing onto discharge areas - it is very important we take a catchment approach to better manage seep areas," he said.
The Bonds are trialling lucerne on non-wetting sands above another major seep elsewhere on-farm.
Kevin said the trials made them realise the importance of identifying seep-prone areas earlier and managing them before they scald.
"Often when a seep starts, the area grows really well, but over time that spot then gets wetter and wetter that it starts to affect germination as it starts to scald," he said.
"Now we know that's when we should put a summer crop in on them before it becomes a problem."
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