AgForce partnered with the University of Queensland’s Centre for Recycling of Organic Waste and Nutrients to host an excellent seminar and forum attended by around 70 farmers, scientists and agronomists in Toowoomba on Monday, 12 August. The latest research into deep ripping and applying composted manures to the subsoil shows that this increases the capacity of paddocks to hold more soil moisture – helping to achieve better environmental outcomes while significantly improving the yield potential.
The first block of speakers shared their experience from subsoil manuring in Victoria. Dr Renick Peries, a soil and water scientist from Agriculture Victoria, and Robert Binks, the General Manager at Yaloak Estate, outlined the benefits of applying subsoil manure which helps to connect the topsoil and the subsoil and enables plants to develop deeper roots, making more soil water available to plants while at the same time helping to “increase the bucket” and enable the soil to store more water. One of the big challenges to subsoil manuring was tackled by the Barry and Sam McFarlane from Bio-Til who spoke about the challenge to design and manufacture machinery that helps to apply subsoil manure at the right place at the right time.
One of the biggest untapped resources for agriculture is urban organic waste. Andrew Dougall, an agronomist and the Organics Strategy Lead with Sustainability Victoria, spoke about how farmers can be part of the waste solution for the cities by using composted green and food waste in their farming system. With a bigger and bigger push for a circular economy, Andrew outlined how farmers he speaks to feel like they can use the nutrients and carbon in urban organic waste in their farming systems. One of the biggest problems to using urban organic waste is to have proper bin segregation to avoid contamination. Andrew was confident that the general public can be encouraged to do their bit by raising awareness about using their green waste on farm land.
The second set of speakers gave an overview over Queensland’s experience in deep ripping and applying inorganic fertiliser in the subsoil. Mark Crawford, a Land Resource Officer with the QLD government, gave the advice to always take plenty of soil samples before making any decisions about disturbing the soil because different soils reacting differently to deep ripping and manuring. Dr Yash Dang, an eminent scholar in soil and nutrient management from the University of Queensland, explained different soil constraints in the topsoil and the subsoil and gave an overview over the different chemistry of different soil types.
Following on from this, Dr Stirling Roberton reported on his project to apply a variable rate of inorganic fertiliser to paddocks based on soil samples and explained how farmers can determine the optimal soil sample density. Dr David Lester, a senior research soil scientist from the Queensland Department of Agriculture, spoke about how plants feed themselves and how phosphorus can be applied to the subsoil to help plants feed better and enhance their nutrient supply. Lastly, Wayne Rooney from Organic Nutrients presented the organic soil amendments that Organic Nutrients produces.
Key learnings from the day were that farmers are very keen to start to apply subsoil manure and compost. Remaining challenges for widespread adoption are to get the machinery right, to bring down the cost of soil sampling and ensure that the composted manure and composted organic waste is coming in at a competitive price point.