How can we reduce fertiliser costs? Alternatives like legumes, compost, and bio-fertilisers help, as does the use of technology like drones to reduce application rates. But we rarely investigate repairing our soil ecosystems to improve their natural ability to recycle and supply nutrients to our crops.

Our soil ecosystems haven’t worked well for so long that we’ve largely forgotten about these free ecological services.

By designing our farms and gardens to maximise plant growth for human and livestock consumption, our soil organisms haven’t been able to access sufficient resources to maintain the ecosystems in our soils. Consequently, we have had to rely on fertilisers and other inputs to feed our plants, and we struggle to grow strong, pest and disease-resistant plants and nutrient-dense food, especially when weather conditions are not ideal.

“Our soil organisms have had a lousy catering service: the menu has been limited, portions small, and the service unreliable!” Dr Wendy Seabrook

photo of soil organism

Getting our Soil Ecosystems Working

To repair our soil ecosystems, we simply need to manage our vegetable gardens, orchards, cropping and grazing systems to provide a generous, diverse and preferably year-round food supply to our soil organisms.

Soils with functioning ecosystems contain biodiverse communities of microbes and invertebrates that have had billions of years of on-the-job training to maintain the soil infrastructure and manage the recycling facilities and supply chains. They decompose organic waste materials, convert the nutrients into simple forms that plants can absorb, and release the nutrients locked up in the sand, silt and clay particles, supplying them to plants for reuse.

If you’re thinking, that’s all well and good in theory, but is it possible in my garden or farm? Worldwide, many people use practices maintaining self-fertilising production systems. They mimic the architecture of the native vegetation in their region, understanding that they need to grow and recycle just as much vegetation in their soils to maintain the soil ecosystem without having to resort to using fertilisers to feed their crops.

Colin Seis in Australia produces an annual grain crop, sheep meat and wool, and native grass seed and earns carbon credits using ‘pasture cropping’. He has “virtually eliminated fertilisers“, yet his soil tests show improved nutrient availability.[personal communication, 5/22] Further west, Bruce and Roz Maynard haven’t used fertilisers in their ‘no-kill cropping’ system for over twenty-five years. While their neighbours get higher grain yields using conventional practices, the Maynards have lower production costs and produce more food overall, having integrated livestock into their system [personal communication, 5/22] In the United States, Dave Brandt learnt that he could go to using almost no commercial fertilisers …. and still produce a great crop of corn and beans. Gabe Brown has stopped using fertilisers. Yet his yields are higher than the “county average”.

Graziers use various practices (Holistic Planned, Adaptive Multi-Paddock and Time-Controlled Grazing) to mimic natural foraging behaviour to improve nutrient cycling and the retention of nutrients in their soil. Research over five years comparing the effects of continuous and time-controlled grazing on a property in southeast Queensland indicated that time-controlled grazing is superior in improving the physical and chemical quality of soil, organic material, nutrient accumulation and plant re-growth. In New South Wales, Tim Wright recorded a four to five times increase in available phosphorus along with increases in total nitrogen and potassium in areas with no fertiliser applications for over three years.

Looking at the science that validates why these practices worked was a turning point for how we managed our farm in northern Australia. While we were, like almost everyone else, tackling the issues identified in our soil tests, these producers focused on providing a varied and adequate diet for their soil organisms.

At Hill Top Farm, we now use time-controlled grazing in our paddocks and grow an overstory of legume trees and living mulch in our banana plantation and orchard. It’s taken time to get our soil ecosystems ‘tuned up and running’ again. But we made cost savings from the start by gradually reducing our fertiliser applications, and we now grow healthier crops with “five-star catering” supplied directly from our soil ecosystems rather than via the intermittent and often inadequate inputs we applied!

Plants getting five-star catering

See how we reduce fertiliser costs for our farm and home garden here.

Further Resources

Trial different techniques, and gradually reduce the amount of fertiliser you apply to maintain yields. Soil scientist Christine Jones recommends reducing the amount of nitrogen applied by around 20% the first year, another 30% the next and then another 30% the year after.

Here are two resources from Learning from Nature to get you started

How to Build Healthy Soil – Eco-logically

Eco-logical Principles of Regenerative Agriculture

You may also like to read this article – Compost and Biological Fertilisers – Are they Regenerative Practices?

Alternatively, get all the information you need to develop practical solutions for your farm or garden with these resources published by Learning from Nature.

Front cover Gardeners Build Healthy Soil

Front cover Farmers Build Healthy Soil

Featured image courtesy of the State Library of South Australia

Brachystomellidae photo © Andy Murray

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    2 replies to "How to Reduce Fertiliser Costs"

    • Lorraine Potter

      Thanks for these wonderful resources. Glad to have found you!!

      I volunteer with the Inga Foundation and their integrated program is a game-changer for the humid tropics–organic, regenerative agroforestry with nitrogen-fixing Inga trees–alley cropping. It’s received the IFOAM Organic Award and was just named a finalist for the Keeling Curve Prize.

      Best wishes,

      • admin

        Hi Lorraine – it’s great that you find our resources helpful. We have featured the work of the Inga Foundation as a case study in the Eco-logical Farming and Eco-logical Gardening Handbook. Inga alley cropping is a great example of how we can increase food supplies to the soil organisms operating the nutrient recycling system in our soil. Did you get the chance to watch this video? Wendy sent Mike Hands an earlier edition of the Farming Handbook a few years back. He may still have it on his bookshelf!

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