A simple DIY test for farmers is a cost-effective way to manage nitrogen levels in soil, a three-year project has shown.
“No organism exists in its own right. It’s always an interaction between living organisms, and soil itself could be classified as a living organism,” he says.
Osborne recently had the chance to explain his philosophy when he hosted field trips for attendees of the Foundation for Arable Research conference at Lincoln.
“850 million years ago the first life forms on land were a symbiosis of fungi and bacteria,” he explained. “And the first plants were a symbiosis with fungi on their root systems. Those fundamentals hold true today.”
Osborne practises what he preaches but also points out that he’s still learning.
What was 20 years ago called conservation agriculture is nowadays more commonly called biological or regenerative farming. This is characterised by no tillage, co-planting of species that support each other, leaving crop residue on the ground to feed the soil, and minimal chemical intervention.
Osborne says reading up on biological farming “really spun” his wheels.
“It’s got plenty of scope for failure so you can get some disastrous results and learn some spectacular things,” he explained.
“I know they say when you shove your finger in the light socket you get an electric shock, but I’m actually going to do it because I want to know what it feels like.”
The first thing eliminated was a lot of PKS fertiliser, after soil tests sent away to the Environmental Analysis Laboratory in Lismore, Australia, showed “massive amounts” of everything the land needed.
Osborne says the key is learning how to harness it and that’s where biological function came in. A combination of cover crops and residue retention builds up humus in the top layer of the soil.
“But the real key is the carbon pathway through having a growing plant pumping down into the roots and exuding carbohydrates into the soil to feed the soil biome which then feeds back to the plant.”
This approach is epitomised by the paddock of ryegrass being grown for seed, where the FAR field trip visitors gathered. The ryegrass was drilled along with crimson clover and the herb phacelia, and at this stage of the crop it’s the feathery fronds of phacelia that completely dominate the paddock.
Osborne says the traditional view is that all plants compete with each other for space, light and nutrients, but he says that’s not actually the case. He says the exudates that come out of the roots from different plants can perform together to improve the soil biology, which in turn leads to the plants being fed properly.
“What I’m trying to achieve, and what I’m learning, is finding plants that grow well together,” he told field day attendees. “Not just co-exist, but actually enhance each other’s performance.”
He says the ryegrass paddock had far more weed-suppressing growth than it would have from any of the three species planted alone. Meanwhile, Osborne added that the mix of legume, herb and grass created a more diverse food source for beneficial bacteria, fungi, insects and nematodes.
For the next step, the paddock will be grazed by sheep throughout winter.
Osborne says the ryegrass would – counterintuitively – be grazed “to within an inch of its life”. But adds it would then “go nuts” in spring, producing seed for harvest in about January.
The phacelia is not expected to survive the grazing, and any clover that survives would not be enough to contaminate the seed crop at harvest, he says.
Once the crop is harvested, the straw will be left on the paddock which will then be grazed until the following spring.
Osborne says he will use the longest rotation possible – at least four years – before putting seed ryegrass in the same paddock again.
No spray, less weeds
“Since I've been doing this I haven’t had to use herbicides to clean up weeds,” Osborne explained.
“Plants change the soil physically and they change it chemically. If you have the right change in chemistry then it does a whole lot of beneficial things for you further down the track.
“One of those things is a less favourable environment for weeds to grow.”
This year his farm will produce linseed, peas, vetch, oats, hybrid radish, wheat, ryegrass, some phacelia and crimson clover for seed, and a bit of hemp.
“When it comes to cropping you’ve got to find groups of plants that work together, to make it less favourable for those off species, which in another part of your rotation you might be trying to encourage,” Osborne explains.
“Often our best crops are our worst weeds. You’ve got to change that year to year and I’m still exploring the possibilities and learning a lot.”