THE CLIMATE KELPIE BLOG: Strict attention to moisture conservation drives grain production in the Wimmera

Posted by BCG on 9th November 2020

Victorian grain grower Tim Rethus describes his family as ‘moisture farmers’.

“Moisture is critical for us,” he says, “Rain dictates yield, so managing seasonal variability depends on being able to conserve every bit of moisture we get.”

While many of the tools and practices they’ve adopted are commonplace, it is their one hundred percent commitment to focusing on their strengths and doing what they do well that has made the difference to their business.

Grain grower Tim Rethus.

Tim’s grandfather, Gordon, moved to Horsham from Nhill in 1947 chasing more reliable moisture for his mixed-farming operation. The family’s philosophy is simple; “If we improve moisture, we improve the bottom line.”

Today, Tim, his brother Luke and father Geoff crop 5,000 hectares across three locations with the assistance of two full-time staff. The Rethus family have transitioned away from mixed farming to continuous cropping and now grow wheat, barley, canola, lentils and faba beans as well as vetch and oaten hay.

“It’s important to stick with your strengths,” says Tim, “Our business is focused on continuous cropping, but conservation and soil husbandry are at the core of every decision we make.”

The Rethus family grow lentils and other pulse crops to retain soil moisture and improve soil nitrogen to the benefit of the subsequent cereal crop.

Focus on soil moisture

“Dad started this process many years ago when he transitioned to sowing with narrow points and used knockdown herbicides to conserve moisture. The old approach of tilling the soil was time consuming and expensive, not to mention the damage to the soil.”

“Since then we’ve kept up with the latest research; adopting stubble retention, disc seeding and zero till. These improvements create a micro-environment in the standing stubble that reduces the air flow over the soil, protecting it from drying out.”

More recently they’ve implemented controlled traffic farming (CTF) to reduce soil compaction.

“We realised that we were trafficking a good 44 per cent of the paddock across a full season,” Tim said. “When we looked across the paddock the crop was growing in waves. Where we had driven over the soil the ground was compacted and the crop starved of moisture either because the roots couldn’t penetrate the soil to find enough moisture or the moisture never made it into the soil in the first place.”

Oats showing wheel track waves and lost potential (height and yield) in compacted soil zone.

The Rethus family’s CTF system uses wider machines with narrow, high flotation tyres or tracks − such as a 48-metre boom spray with 480-millimetre-wide “VF” (Very Increased Flexion) tyres − and everything is matched up, including the hay making equipment. Tim estimates they only traffic 12 per cent in their 12 metre system or only two per cent of the paddock in crop with the boom spray.

Tim says that controlling traffic effectively means you crop more land from the same paddock area and that is a much cheaper way to expand production than by buying more land.

As much as possible, soils are trafficked when dry to further reduce the damage. “In general, the sprayer and spreader are the only machines that will run on wet soils. We use inflation kits on the sprayer tyres so we can reduce the tyre pressure to spread heavier loads and tracks on the spreader tractor,” says Tim.

Adopting controlled traffic farming with wide machinery and narrow tyres (or tracks) has substantially increased the area of the paddock that is productive; “It’s cheaper than buying more land,” says Tim.

Agronomic advantage

The family sow early to maximise water use by the crop and grow a wide range of crops to provide more options for weed and disease control.

“We sow by the calendar, starting April 1st with hay crops that are not frost-critical and then canola, which we aim to have germinate by Anzac Day. We often have around two thirds of the crops in the ground before early-May, which is when we typically expect to get breaking rain.”

Dry sowing with a disc seeder limits weed stimulation and conserves soil moisture allowing crops to germinate before the traditional seasonal break. Early sown crops germinate into warmer conditions and quickly produce ground cover that both reduces evaporation losses and will crowd out any weeds that germinate.

“We grow the latest varieties to get the best breeding technology. We’re looking for varieties that we can sow early and yet will not flower too early and be exposed to frost damage. We can get a frost as late as the first week of November, so obviously trying to pick the perfect flowering window is impossible, but by focusing on growing a healthy crop we put it in a good position to withstand challenges such as frost or pests.”

In paddocks that are particularly prone to frost they favour a hay crop or faba beans, which are more resilient to frost. The family have their own hay-making equipment and, if necessary, can cut any frosted grain crops for hay in a timely manner to preserve quality.

The 48-metre boom spray is an integral part of the strict controlled traffic system.

Playing the long game

“We tend to stick to our rotation plans regardless of seasonal conditions and grain prices. Chasing a quick profit in one year can come back to bite you in the following year,” says Tim. “Our rotations are planned to look after the soil and minimise weed and disease pressure. They include vetch-based cover crop brown manures to reduce weed populations, recharge the moisture bank and improve the soil.”

“We use the different crops to play with rooting depth. Pulses are relatively shallow rooted so they conserve moisture at depth as well as providing some nitrogen for subsequent cereal crops.”

A 65-kilometre geographic spread between their paddocks, means that slight differences in soil type and rainfall can spread risk and help to balance income. 

“It’s important to be in control of the system to maximise your options,” says Tim.

“We can see the difference that moisture farming has made to our crop yields and the bottom line. But we’re also seeing the impact on the land. We don’t get the run-off into farm dams anymore. Every drop of rain is retained in the soil. For us that means in 2019 we could grow a decile six crop on a decile three rain.”

“It would be good to see what this area looked like 200 years ago. There was a lot of damage done in the first hundred years of settlement and I’d like to think that we are making at least some progress towards returning the land to a healthier and more productive balance.”


Tim Rethus, 0425 791 651,  

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