Soil cover is everything

April 14, 2019

This article appears in the Vic No-Till Members Magazine From the Ground Up, Spring 2018 edition. We print three magazines a year and post to our members, with the focus on innovative Australian farmers such as the Ranford family: more membership details. 

Aspiring to be a ‘soil builder’

By Melissa Pouliot

Eyre Peninsula farmer Ben Ranford predicts the transition from no-till to regenerative farming systems being as big, if not bigger, than when Australian farmers started moving from cultivation to no-till more than two decades ago.

“We are in the midst of a really important change here in Australia. Just like we can’t imagine agriculture without no-till, this shift to recognise the importance of soil biology and groundcover in our cropping systems is massive.

“I’ve just turned 50 and it’s great to have a new horizon and something to get excited about and engaged with. Regenerative ag has added a whole new dimension for me to get more interested in what I’m doing on my land.”

Ben and Kathy are fourth-generation farmers on Ben’s family property between Cleve and Arno Bay in South Australia.

Ben returned to the farm in 1989 after completing an Agricultural Science degree at Roseworthy Agricultural College which is part of Adelaide University. He and Kathy worked alongside Ben’s parents John and Diana until they retired in 2016. Their children Phoebe, Jade and Skye – all at university – and son Oscar in Year 8 at high school, are involved on the farm between study, especially during harvest. Ben says they also have a right hand man, Graeme Dolphin, who is tuned into new technologies, a tireless worker and a great part of their team.

Resilience

‘Bermondsey Park’ is now 3000 hectares in a district characterised by highly variable seasons. With an average annual rainfall of 325mm, during the past 25 years rain has varied from a high of 600mm to a low of 122mm.

Ben says this makes it important to be resilient and maintain potential for success after tough times.

“Highly variable seasons create highly variable production results. Strong winds are a major concern for crop production with historical soil losses from wind erosion, and damage to crops from grain loss from flowering to maturity,” he says.

“It’s not easy to stay positive and proactive after a couple of poor seasons in a row when the result has let you down, but it’s critical to focus on bouncing back when conditions turn around.

“Organise finance, seed and inputs as early as possible, have a plan A and B and have the team and machinery ready to roll. Farming is a roller coaster and the 80:20 rule applies: we make 80% of our profit in 20% of seasons so you can’t afford to mess up a good one.”

Transition to zero till

Until the end of 2016 the property included a self-replacing Merino and prime lamb enterprise but they sold the sheep to focus on developing more diverse crop rotations and improve soils. They worked hard to balance their sheep and cropping but the combination of soil goals and a review of their overall farm profitability guided the decision to get out of sheep.

“Grazing pressure often resulted in damage to soils, especially our lighter soils. Then I used to double sow a lot of sand hills when we cropped after sheep grazing, and still had to worry about getting them covered before the wind created problems. Those areas are more stable and productive now without the extra inputs and risk.”

They used to manage grazing by strategically fencing to soil type and making paddocks an ideal size to rotate stock through.

“Doing that was exactly the opposite of the open, unobstructed layout suited to wide machinery, GPS guidance and Controlled Traffic. I wasn’t prepared to compromise anymore so that’s when we decided to focus 100% on crops.”

Taking livestock off to maintain soil cover and stop compaction has been one of the latest changes of a multi-layered evolution of a farming system that is gentler with their soils.

They started no-till techniques in 1994, and since then have followed the new ideas introduced by the South Australian No-Till Farmers Association (SANTFA) and Vic No-Till.

“I felt like we were all pioneers together 20-plus years ago developing the tools and agronomy of no- till, but once we had that sorted I did lose interest because there were no new frontiers for quite a while. The biological focused, regenerative approach to farming and seeing what others are doing has really got me fully engaged again.”

In 2016, as part of their zero-till transition, they adopted a 12-metre based Controlled Traffic Farming (CTF) system with a Tobin Bullet single disc seeder on 12-inch (30.5cm) spacings.

“I’m implementing this approach as my understanding evolves through following the progress of successful, innovative farmers across Australia and around the world who have shared their soil building experience through SANTFA and Vic No-Till.”

Soil use efficiency

Ben’s greatest incentive to change approach is a desire to improve soil-use efficiency for crops.

“There’s no doubt our greatest limitation, and one we can strive to understand and improve, are our soils. Historically we have seen massive, up to four-fold, variations in growth and grain yield across cropping paddocks where the area has received the same amount of rainfall and inputs. The variations are soil based issues and we are not using moisture and nutrients efficiently. So I aspire to be a ‘soil builder’,” Ben says.

Regenerative ag concepts have taken their crop and soil management in a new direction with the aim of reducing the soil’s texture and available nutrient limitations. Diverse crop rotations, companion cropping and eliminating pesticides that are harmful to beneficial biology are all part of an approach that builds and protects healthy, fertile soils.

“Our soil’s health and its capacity to supply water and nutrients to plants is the key to sustainable, profitable crop production.”

Timing

The timing of taking their system to the next level has been partly luck, but critical to getting a result, with 2017 being a ‘very dry’ year followed by what is an even drier one in 2018.

“Last year was very dry but we managed a 15mm rain event in early April so what we had sown dry in front of that rain established really well. Most of our programme emerged strongly from that moisture, even deeper sown lentils two weeks later. We had some subsoil moisture and those crops never looked back.”

They didn’t get follow up rain until July but were amazed how the crops kept growing.

“Our soils are not renowned for supporting crop growth for that long without rain. But the 15mm was enough to get their root systems down to the subsoil moisture and they looked quite content sitting there for three months before they got another drink.

“I put that down to sowing with a disc seeder and the fact we didn’t lose any moisture doing so. Also, the liquid nutrition increasing root growth and helping connect with soil biology.

“When they got any rain after three months the cereals kept tillering when I thought they would run to head. The way the plants paced themselves through that season was just amazing.”

The total growing season rainfall (GSR) for 2017 was 142mm and despite losing some of their best crops to frost, which is most unusual in their experience, Ben describes their yield potential as a standout.

“The wheat which got frosted I’d insured at three tonnes to the hectare; it would have been sweet to get that result in the bin.”

Liquid nutrition

Last year was also the first using liquid nutrition, something they’re continuing as the liquids appear to provide more gentle balanced access to nutrients.

“Our approach to nutrition has moved away from high analysis granular fertiliser to all liquid in furrow at seeding.

“In marginal moisture at germination we have observed our crops establishing steadily and healthily compared to surrounding crops sown with compound N:P which have a growth spurt then ‘hit the wall and go blue’ from too much nutrition when they just need water.

“The plants aren’t showy early in the season but both last year and this year they have refused to give up in hot, dry spring conditions. They have filled grain very well and been more even across the paddock than what I expected.”

Stripper front

Another change they introduced last year was using a stripper front to harvest their cereals.

“We want to keep our stubbles standing up to buffer the soil surface from sun and wind. This creates a micro climate at ground level which is much more supportive for crop establishment compared to bare soil. Standing straw and eliminating header rows of residue also improve crop establishment with the disc seeder as it minimises hair pinning into the seed bed.”

Ben says a welcome bonus from using the stripper front is the increased productivity.

“We haven’t had good enough yields to test the limits but it was obvious how much more grain we could process at higher ground speeds without taking in any straw. Fuel consumption was much lower and the machine ran cooler and stayed clean.”

Warm season covers

The timing of 77mm of rain in November and December 2017 allowed them to build their system even more by introducing warm season covers.

“We hadn’t sown warm season covers before, but we had the seed all ready and getting this rain was a real catalyst for having a crack.

“We’d normally harvest wheat together to optimise the chaser bin but Graeme was so impressed with the stripper front he wouldn’t let me near the wheat with the conventional front on the other harvester. This freed me up for the covers.

“Each morning while I was waiting for the moisture to come down, I’d sow where we’d harvested lentils or wheat the day before. Then when it warmed up I would jump off the seeder and continue harvesting.”

Ben planted warm season covers into more than 2000 of their 3000 hectares including the bare lentil paddocks and wheat stripper straw paddocks. He selected sunflowers and millet as he felt they would provide different benefits to the soil and complement each other.

“The aim was to get some cover back on the bare lentil ground that had been close shaved with a flex front. Also to push roots deeper into the subsoil to access and recycle nutrients and build organic carbon in the soil, basically the ‘ice breakers that future crop roots can follow’, and food for biology.”

This got the neighbours talking and generated some banter around the district.

“Considering we’re in an area where the conventional wisdom is to have a chemical fallow over summer to stop anything growing and conserve any moisture you might have for the next winter crop. What I did was pretty much the opposite and I was getting regular feedback that if we had a dry  year, I’d lost any chance of growing a crop because the summer plants would have used all the moisture and nutrients.”

As it turned out, 2018 has been exceptionally dry. At the end of October they’d had 161mm for the year.

“Out of the 130 GSR we had 77mm in August and October. The other 50mm was spread across five months and all fell in less than 5mm windy events, making it largely ineffective. If we’d had six 25mm rain events all staggered out nicely with no destructive winds it would have been plenty of rain! But the reality is, this year has been really unhelpful for trying to grow a crop.”

Ben says 2018 provided a strong example of how important a ‘decent’ rain is to get things up and going.

“Although it was dry in 2017 we had good subsoil moisture and decent rain to get things going. But in 2018 we just didn’t get effective rainfall to get things going. So even though the rainfall totals aren’t all that different, there is a big contrast between the results.”

Even so, Ben is amazed at how well the cereals and lentils established without good moisture at or after planting. Unfortunately, not so for the dry sown canola which had patchy emergence and mostly did not see the light of day.

Wind erosion

To add insult to the injury, 2018 has delivered extreme wind. Ben says if he hadn’t covered two-thirds of his paddocks with summer crops, he can’t bear to think about the wind erosion he would have suffered.

“If I hadn’t grown those covers and didn’t have that residue I would have terrible wind erosion on a lot of the lentil ground. As it turns out the wheat crops on those paddocks are finishing as well, if not better, than the crops around them. And that’s taking into consideration that we only had 4mm of rain in September when they were coming out into head and flowering.”

He wouldn’t argue for one moment that he didn’t use up all the available moisture with his covers but attests that something more powerful is going on.

“There’s something in play that’s as important than that stored moisture and I believe it’s the habitat we created with those covers, and how it promoted the soil biology. That soil biology supported the crop through the dry year and has somehow given the crop what it needs to grow and yield well in very challenging conditions.”

When Ben says ‘yield well’ he is expecting wheat to average one tonne per hectare. “Those yields don’t sound very impressive but with high grain prices it is cash flow, and the paddocks are in good shape for next year.”

Topsoil loss

What Ben finds heartbreaking is the amount of lost topsoil in his district. On his farm it’s not all perfect either. He has 200 hectares which has succumbed to wind erosion where he hasn’t been able to get any plants established.

He lost the cover off these areas after seeding. He knows exactly what he did wrong that led to this result and has learnt a valuable lesson.

They sometimes use a steel land roller for rolling stubbles to kill snails. In previous years, using knife-points and press wheels, there was enough space in the furrow for stubble crowns to be protected and not get completely crushed by the roller.

“But after sowing with a disc the ground was pretty much flat and the roller snapped the straw off right down at ground level and mashed the crowns. I went in thinking I was doing a marvellous job, during a heatwave over summer, snail guts central and no straw standing up for survivors to perch on!

“I got caught out because I didn’t appreciate that subtle difference of having a little furrow from the knife point versus not having any furrow with a disc.”

Even though the stubble was lying flat on the ground, it wasn’t connected to anything.

“When we got extreme winds the straw blew away and left flat, bare soil, setting me up for a wind disaster. I have paid a high price for disregarding the importance of standing stubble. From now on, snail bait.”

Cover, cover, cover

Ironically, the years of work he’s done to improve his soils has contributed to them blowing away so easily.

“It’s just a cruel reality check that our soils are extremely fragile. Once you lose the cover on them, it’s awful the impact that has. I’ve been horrified at how easily our nice, soft, loose soils – uncompacted with a lovely mulchy soft layer of topsoil – have blown away once the cover is gone.

“Some of these soils that have blown away used to set pretty hard when they dried out but now, after no till then zero till and no grazing, I can drag the full length of my finger through them so it’s no wonder they blow away so easily.

“It’s not good enough to build up your soils – you’ve got to cover them or risk losing it all. Buffering the soil surface from the elements has moved to our number one priority.”

In September Ben went in with a summer cover mix of sunflowers, millet and corn to try and get some groundcover onto those paddocks, as well as on his failed canola ground.

“We began sowing warm season seeds in late August when the soil was still about 8 degrees Celsius in the morning but about 14 by late afternoon. Sunflowers came up much better than millet; it was October before the millet came up. The wind has knocked them around and the millet is the least tolerant of sand blasting when it is only two-leaf.”

With only 4mm of rain in September, not much germinated and they waited for a rain event to continue seeding. It didn’t come until October.

“We hung back because there was no stored moisture and we didn’t want to risk making a bigger mess playing with dry soil. It is the land most exposed and bare that is the hardest to get established.”

In contrast, where residue is giving protection and moisture retention the seedlings have come up and hung on through six dry weeks then grown with every small rain event. Now, in early November, most of the warm season cover paddocks are looking green and the sunflowers are leading the way.

The worst erosion areas are still not covered. Some have been sown and cut off by wind, while some they are still waiting for a significant rain event to have a go at.

“Without enough moisture we risk making the soil more exposed to erosion just by running over it. If we get a big rain anytime this summer the seeder is hitched and full, ready to go. Bring it on!”

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