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There were a number of thought-provoking, take-home messages from the recent two-day National Biological Farming Conference.
While the event was organised by the National Organic Training Skillnet, the conference was attended by producers from numerous production systems including conventional, conservation and organic.
Biological farming
Biological farming is a system which focuses heavily on the role of soil biology in plant production, as well as soil chemical and physical properties, explained Joel Williams, a Canada-based independent soil and plant educator who spoke at the conference.
Biological farming essentially aims to balance the entire agronomic, environmental, nutritional, biological, chemical and physical components of what constitutes a healthy soil.
Truly healthy soils will deliver a range of benefits including lowering input and establishment costs, lowering pest and disease pressure and producing more nutritious food, he explains.
New way of thinking
He explains that we’re in the middle of a transition between an old way of thinking about soil into a newer, more complete way of understanding it.
The old view was based on the principle that plants release organic acids through roots, which directly solubilise minerals from the soil, in turn making them available to the plant.
The role of soil microbial life was essentially ignored, he explained.
The new understanding very much focuses on the interaction between other root exudates and soil microorganisms.
Plants excrete numerous other root exudates which don’t directly solubilise minerals in the soil, but instead serve to feed these soil microorganisms.
These microorganisms help cycle nutrients, in turn making those soil nutrients available to the growing plant.
Root exudates
Root exudates describe substances released from plant root systems in small quantities including carbohydrates, organic acids, vitamins and many other substances essential to sustain soil organisms.
Soils contain billions of bacteria, nematodes, fungi, protozoa etc. All these organisms feed on these root exudates, which typically only migrate 1-2mm away from the root before being intercepted and consumed.
The middle ground
Joel said the existing divide between organic and conventional agricultural systems is shrinking, and there is a new middle ground developing.
Both conventional and organic farmers are moving into this biological farming middle space and continue to explore new ideas and techniques, while still being production-focused.
Joel’s top biological farming practices
Based on his experiences and observations from around the world, Joel developed his top 10 practices of biological farming.
1 Designing with diversity
First and foremost, Joel explained the importance of redesigning production systems. He put this at the top of the list for an important reason. He said integrating more ecology into the system is crucial. This can be achieved through as simple a measure as growing cover crops or intercropping.
The main aim was to move away from this traditional mono-cropping system and promoting plant diversity. He spoke of the benefits of having roots from different species reach various depths of the soil profile, each of which could tap into minerals at different levels.
2 Feeding soil biology
The principle is simple – always have living roots to feed soil microbiology. Roots produce hundreds of exudates but the benefits of many of these remain unknown to researchers.
Recent research has shown that plants can produce certain exudates in response to stress that can attract specific soil microorganisms. These microorganisms can, in turn, make specific nutrients available for the growing plant which help relieve the symptoms of stress.
3 Manage soil organic carbon
Directly applying carbon sources such as compost, mulch, digestate etc is one method of incorporating carbon into the soil. However, Joel explains that growing carbon through photosynthesis is much more economical.
When a plant is growing it sequesters carbon. Joel estimated that roughly 20% to 30% of the total carbon taken in by cereals is pumped down to feed microbes. This figure increases to 30% to 50% for perennials. Encouraging greater plant growth and increasing root exudates will contribute to increasing sequestration levels.
4 Minimising soil disturbance
He acknowledged that not everyone can adopt zero-tillage as it will not suit every system of farming, soil type or climate. However, every producer should be aiming to minimise soil disturbance.
This is important for protecting soil aggregates which are key for carbon storage and creating soil structure. The presence of mycorrhizal fungi is an important factor in supporting the aggregation of soil particles. When soil is cultivated the disturbance breaks these aggregates.
5 Remineralisation
Joel said minerals are essential for the syntheses of more complex products such as proteins, fats, oils, amino acids, hormones etc, as well as being crucial for photosynthesis.
Farmers are photosynthesis managers, which means they must ensure the minerals required for crop growth are available. This may require more detailed analysis of the soil.
For example, molybdenum, iron, nickel, cobalt, calcium etc are all elements which are sometimes overlooked in conventional soil analysis, but each have their role crop growth.
6 Reduce synthetic inputs
“We’re incredibly efficient at being inefficient with nutrients from the bag,” says Joel. He estimates that only 50% of applied N that reaches the plant is taken up by the plant, around 30% of P and around 40% of K. This obviously depends on a variety of factors. Soils have a bank of minerals which are insoluble, and which the growing plant can’t access. “You need biology to help access those,” he explains.
7 Integrated nutrient management
Joel spoke of the need for integrated nutrient management and developing strategies to improve nutrient availability. This could mean combining organic-based inputs with inorganic inputs.
Rather than apply nutrients in a highly soluble form on their own, he suggested combining them with a carbon source which will help bind and stabilise that nutrient. This should make it less leachable and subject to lock-up.
8 Foliar management
This is an important piece of the puzzle, he explains. By using a targeted foliar-applied mineral application, you can help boost crop health and performance, when the crop needs it.
This will help drive photosynthesis and increase root exudates which will help to drive more nutrient cycling in the soil. This will help increase nutrient availability.
9 Livestock integration
He said livestock can bring a range of benefits to the soil ecosystem, mainly through dung. Livestock dung is loaded with microorganisms and can bring new ecology into the soil.
10 System thinking
The final practice involves looking at the bigger picture and realising that soil is not as simplistic as it is sometimes portrayed. But once you can look at the bigger picture, you can identify key areas to target investment.
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