REGENERATIVE agriculture is about working with nature to 'regenerate' the soil which over time should enable the farmer to reduce their reliance of synthetic inputs and ultimately lower production costs.
That's the aim of Kangaroo Island mixed farmer and agronomist Jenny Stanton, who recently ventured across to New Zealand to learn about the long-term soil recovery strategy from soil ecologist Nicole Masters.
Partially sponsored by the KI Achievers Trust, Ms Stanton undertook a three-day Certificate in Regenerative Ag Systems course at Leeston, south of Christchurch.
"Living on KI, farmers are always contending with high freight costs and the logistics with our inputs, so I have become increasingly interested in reducing our input reliance by working with nature and interpreting its indicators," Ms Stanton said.
"A fellow consultant once said to me 'Everything is everywhere; nature selects'. This saying applies equally to weeds as it does to livestock diseases/conditions.
"The nutritional integrity of the soil or animal dictates what desirable plant or weed proliferates or likewise if the animal succumbs to disease. It's no different to a person with poor nutrition - they are more likely to succumb to a cold that's getting around.
"But if they have good nutrition from a nutrient-rich diet, then they have a strong immune system to fight attack."
Ms Stanton said increasing groundcover and biological activity were important in improving soils.
"If you have living plants (preferably year round), converting sunlight energy and carbon dioxide into liquid carbon that leaves as root exudates this leads to an increase in soil organic carbon levels and thus water holding capacity," she said.
"More importantly these root exudates feed the microbes in the soil and this is where the magic happens.
"In return, the soil biology supplies plants with microbial nutrition so the plants expend less energy taking up nutrients and thus the surplus energy is converted into fats and lipids in the plants. When this is achieved the animals spend less time walking around eating.
"They need less feed to satisfy their nutritional requirements because each mouthful is more nutritionally/energy dense.
"But your plants must have access to the key nutrients required for optimal photosynthesis and fast protein synthesis before the plant will invest diverting liquid carbon as root exudates."
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Ms Stanton said regenerative ag takes indications from nature, particularly weeds, to determine possible soil deficiencies or excesses - a topic studied during the course.
"Weeds generally appear to fix a soil problem, and as farmers, our job is to intervene, figure out what that weed is trying to tell us and then change the soil conditions to improve the soil and encourage more desirable plant species," she said.
"The most problematic weeds on our farm at Stokes Bay are silvergrass and capeweed.
"I am putting a lot of energy into trying to manipulate the soil conditions to deter silvergrass, which isn't very productive and can quickly dominant the pasture sward.
"It also releases alleopathic chemicals which can inhibit germination and growth of the desirables the following season.
"Silvergrass can often be an indicator of low phosphorus, but I know of other farmers that have a strong history of P fertilisation who still have the problem.
"Phosphorous is certainly something we are addressing, but in sand where we have our worst silvergrass problem we can get leaching of P, so we are mindful of that.
"Sometimes though it might not be that straight forward.
"From all the soil tests I have done, they have come back consistently low in boron, which can compromise calcium uptake.
"So potentially, if silvergrass is an indicator of functional calcium deficiency, we could put boron out to improve the uptake of calcium and that may help reduce the issue."
The aim is to gradually increase the biological activity of your soil, which increase the availability of favourable nutrients.
Since returning from NZ, Ms Stanton said they have started trialing various applications on-farm with regenerative ag in mind.
"In a part of the paddock with a high silvergrass burden we have applied small test plots of P, potassium, calcium, boron, calcium + boron, magnesium, compost, crusher dust and spread clay," she said.
"I am trying to adjust the soil conditions so that in future years, the conditions may be more aligned to growing clover, ryegrass and kikuyu as opposed to silvergrass and capeweed.
"But these applications will never be a quick fix, like simazine or paraquat.
"Those chemicals have to be used year-on-year because you are not actually addressing the root cause of the problem.
"The root cause is there is a soil condition dictating what germinates and what doesn't, encouraging weed species to thrive.
"The aim is to gradually increase the biological activity of your soil, which increase the availability of favourable nutrients.
"From what I have learnt, the conditions of the soil and its nutrient content determine which weed seeds or desirable plants then germinate.
"Manipulate the soil conditions to make favourable plants happy."
I'm hopeful nurturing our soil microbial life can pay us back in huge dividends in future years.
Ms Stanton said they were also trialing fungi-enhancing products, such as vermicast extract and fish hydrolysate (made from Tuna offal in Port Lincoln), in an attempt to feed the microbes which in turn feed the plants.
"Ideally we want our soils to be more fungal dominant," she said.
"The fish hydrolysate is also high in protein - a good nitrogen source and is a great food source for mycorrhizal fungi.
"Both are not instant remedies, so you have to be patient and wait for the microbial life to repopulate."
But Ms Stanton said there was little point farmers being 'sustainable' if their soils were already in a degraded state. They needed 'improving'.
"Repeated applications of pesticides over the years have disrupted the soil microbial profile so it will be a gradual process to correct the balance in favour of fungal dominance," she said.
"They say it takes about three years to get your soils humming.
"So you may not save money immediately, but you are diverting your inputs to the biggest limitation on-farm, which are guided by soil, microbial and leaf tissue tests.
"If your soil is outright deficient in a nutrient like copper, then you need to address that first because the microbes need them as well. But sometimes the nutrients can be there but are not functionally available for example P.
"This is where I'm hopeful nurturing our soil microbial life can pay us back in huge dividends in future years."
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