Ben Nevis trials Dirt to Soil recipes and the proof is in the paddock

Erica and Stuart Halliday, Ben Nevis Angus, Walcha experienced similar doubts after reading a book suggested by "a mate" called From Dirt to Soil, written by North Dakota farmer Gabe Brown on how he turned his farming systems around to one of regenerative agriculture.

But they say the proof is in the paddock after trialling the methods during four growing seasons.

The backstory to the Halliday's soil renewal trials emerged from the 2019 drought.

They decided to run 600 of their cows in confinement feeding pens for efficiency and economy. Each pen was about two hectares and held 200 cows, and they were fed canola hay. The result was three small, bare paddocks that were compacted and high levels of manure and urine.

They decided to test the recipe proffered by Gabe Brown's book to grow, rebuild and improve the quality of the soils in those two ha pens. After the drought, they sprayed out the pens to combat weed growth.

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For two-and-a-half years, they rotated through cover crop mixtures of winter and summer species mixes where cattle would be crash-grazed onto the feed, consuming one-third, knocking down or trampling once-third and leaving a third remaining.

"So basically that mulch litter would eventually become humus and eventually become soil," Ms Halliday said. "And at the same time, we would grow microbes, grow carbon organic matter and have this magical soil that looks like chocolate cake.

They planted all three pens with multi-species cover crops and, at the end of the winter-growing period, went straight in and planted a summer species mix.

All three pens were established with an initial knockdown spray of Roundup. In the third pen, a traditional industrial agriculture method was employed, where it was sprayed out with a knock-down of glyphosate before the multi-species mix was planted each time.

Of the two plots with no spray pre-planting, one had an application of synthetic fertiliser, while the third had just vermicast (worm castings) and cow manure. They ran the same stock rates in all three plots in high-density grazing for the same stock days per hectare.

The results were remarkable for the plots where no spray was used.

"Basically, the NPK (nitrogen, potassium and phosphorus) were the same, and organic matter was about four per cent," she said.

"The soil in both those instances looked pretty good. It had become a rich, dark colour and quite friable. Interestingly the one using only vermicast and cow manure had 38 per cent more microbes and a desirable 1:1 fungi to bacteria ratio, while the others were bacterially dominant.

"The third plot still looks like white chalk, and these three sites are just 50 metres from each other.

Their agronomist, Gary Littlejohns from AMPS, created the two seasonal seed mixes. The winter mix includes rye corn, a deep-rooted species, ryegrass, tillage radish, turnips, hairy vetch and oats. In the summer mix, there are sunflowers, safflower, millet, buckwheat and a mixture of vetch and clovers. Ms Halliday said pasture surveys had noted that plantain and chicory were growing well, but this seed was not in the mix and was volunteering from another source.

Trials with mobs of bulls on the multi-species mixes compared with straight forage oats also revealed pleasing results.

"We measured how the bulls were doing on the multi-species mixes as opposed to straight oats, and the bulls did 200 grams a day better on the multi-species, and we had fewer incidents of pinkeye and foot abscess.

The Hallidays also measured microbial balance and microbial levels between the plots. The plots that didn't have any spray had higher microbial populations.

The costs of the three trial plots also were clearly defined. Plot three using the glyphosate and synthetic fertilisers was $428/ha, the plot with no spray and synthetic fertiliser was $371/ha, and the plot with a no-spray with organic worm vermicast and cow manure regime was $263/ha.

Cow manure was from a feedlot on the Liverpool Plains, and while relatively cheap at $16/tonne, the freight cost was $39/t to transport it to the Walcha district.

Ms Halliday said they are working with a company called Multikraft which is trialling the use of probiotics on manure to break it down quickly and have a nutrient value ratio of 1:3 for the volume of product. This would be a breakthrough if successful as it would dramatically reduce the volume of the product needed at the time of application, she said.

She said a disturbing revelation with the plot that has had the five applications of Roundup is that it has minimal microbial activity.

"So with all the rain we've had, it's got pools of water everywhere and low oxygen levels in the soil. The soil is still compacted, and there's no water cycling through the soil.

She said the soil microbe population in the three plots also varied dramatically.

On a broader scale, the Hallidays are now testing the application of the organic mix of manure and vermicast against applications of urea.

"We've got other improved pasture mixes, and on the left-hand side of each of those paddocks, we spread manures, composts and Vermicast, while on the other side of the paddock, we do traditional urea, and we're looking at differences there too.

"At the moment, there are no differences between them. There's no difference in the amount of feed grown, but one's cheaper than the other.

"I think when we go and measure the microbes in that paddock as well, we'll probably have a higher microbial load, and we'll be better off with a system where the microbes feed the plants as opposed to us directly feeding them at a higher cost.

"It sounds too good to be true. I know.

"Which is exactly why when we read the book, we thought, well bugger this, we're going to do our trials, and so you know, it's not like we're scientists or anything like that. We had three paddocks in the same vicinity, and the same soil type had been treated the same. And we thought, let's run a trial in each paddock, and these are the results we've measured."