On-farm composting – Status, Barriers, Opportunities
Dr Kevin Wilkinson

The intensive animal industries in Australia are familiar with composting as many farmers use it for managing manures and other organic residues. However, given that it is not their “core business”, farmers can also be uncertain as to whether it is right for them or not. Making well-informed decisions about this subject can be daunting – there are many different aspects to consider and there is no such thing as a “one size fits all” solution to composting. In some cases, composting is essential for a farm’s continuing licence to operate, in other cases a new business opportunity may emerge when composting is conducted in partnership with a specialist contractor or external supplier of organic residues. There is often uncertainty about what is possible at different sites, and in some jurisdictions, regulations may even restrict on-farm composting. Composting provides an opportunity to value-add to organic by-products like manure and mortalities and it can also contribute to environmental sustainability, but like any part of a business operation, it must make commercial sense. We will cover these issues by drawing on both local and international experience in a practical, no-nonsense manner. 

Why consider manure composting?
Prof Robert Rynk

Good question! Because manure is a resource in itself, carrying nutrients and organic matter, it can be beneficially land-applied without composting. Age-old practices confirm that fact. However, age-old practices are increasingly confronted by new realities. Nutrient overloading in close vicinity to intensive animal units or odour-sensitive neighbours or environmental constraints or some other restriction might give an advantage to composting compared to direct land application of manure. Plus, composting usually adds value to manure, making it more attractive to more potential users of the manure, including the source-farm. The next good question to ask is: Does composting add enough value to cover the added cost and effort? The answer depends, of course, on the specific situation but, generally, composted manure can be a revenue source; and it is cheaper to handle, transport and apply than the raw stuff. Use in high-value products, such as growing media and potting mixes, and further value adding, e.g. pelletizing or blending with fertiliser, is usually feasible for compost, but not manure.

Rules and regulations that govern manure management and composting
Janine Price

All Australian states have organic waste processing facility requirements; however, these are often not relevant to on-farm composting and are often incorrectly thought to apply to farming systems.  Incorrect application of regulations creates overly onerous and costly requirements for producers and can limit opportunities for the sale of competitively priced products that can substitute mineral fertiliser and help stabilise soil carbon levels.  Composting requirements on farm are often triggered on the basis of feedstock materials being composted, the source of the feedstock (is it generated on- or off-farm) and whether it is an ancillary operation as part of an existing licence for another activity i.e., intensive livestock farming.  Regulations governing the end use of compost and manures also often vary depending on whether it is used on or off site.  Do you know if your State has an exemption for manure or compost reuse or if this activity is just covered in the general environmental duty? Come along and learn about the manure and composting requirements that are relevant in your State, and where to find help in interpreting and applying the rules and regulations so you can maximise the benefits (fertiliser and financial), while also minimizing the impact on you (regulatory burden, being caught up in regulations) and the environment.

The fundamentals of composting
Prof Robert Rynk

Composting transforms raw organic materials into compost, a soil-like material that its valued for its soil-improving and plant-nurturing qualities. The compost reflects the characteristics of the original feedstocks but it is more valuable, stable and easier to handle. Compost is created primarily by countless and diverse microorganisms that, over time, convert a wide range of potential organic residues into a new product: compost. They change the chemistry, determine the biology and largely affect the physical structure of the materials. The main role of the human composter is to manage conditions to allow the microorganisms to do their job efficiently, timely and with a minimum of ill effects. The major conditions that we human composters need to manage are: (a) oxygen, which is determined by aeration; (b) moisture (not too wet or dry); (c) nutrient balance; (e) physical consistency of the composting materials; (d) temperature; (e) pH; and (f) time.

Planning and setting up a composting operation, including business and operational models
Matt Cotton

What does it take to start composting at your farm? This talk will focus on the details of locating your composting operation, whether on the farm or at an external location. There are numerous competing issues which need to be balanced when siting and designing the operation, the location, the drainage, the scale of the operation, the technology, and necessary mixing and processing equipment, and last but not least the use and possibly marketing of the generated compost products. What equipment do you need?  Is there some equipment you already have that could be useful? How can you minimize environmental impacts? What site improvements might you need? What level of performance is required? This talk will review possible site layouts, design concepts for siting a composting operation on a farm, and share layout objectives. Pad surfaces, processing equipment, moisture management and process monitoring will be discussed. Options for both large- and small-scale operations will also be discussed, as well as the financials of composting and various business and operational models.

Mortality composting
Dr Kevin Wilkinson

Composting is routinely employed for the disposal of day-to-day mortalities in the intensive animal industries. It is also gaining acceptance in Australia and internationally as a suitable method for disposal of carcasses in emergency disease outbreaks like Avian Influenza and African Swine Fever. Composting is a well-established pathogen reduction technology that controls nearly all pathogenic viruses, bacteria, fungi, protozoa (including cysts) and helminth ova to acceptably low levels. It can be a cost-effective option for disposal of carcasses, especially in locations that have high landfill disposal costs, where knackery and rendering services are unavailable, or where farmers are looking for an alternative to burying dead animals. Mortality composting can be simple to set up and operate, or else more complex, enclosed composting systems can be installed. The suitability and affordability of different technological approaches to mortality composting will vary from site to site. The principles and practice of mortality composting will be covered in this talk with particular emphasis being given to the importance of biosecurity.

Compost characteristics and compost use, including soil carbon credits
Johannes Biala

Compost products can vary markedly, depending primarily on feedstock, composting conditions and duration, and any further processing or value adding. Most compost generated on-farm is used as bulk soil amendment in agricultural or horticultural applications. Compost is a multi-purpose product that can deliver a range of agronomic and soil benefits, including supplying plant nutrients and external carbon, improving soil physical properties, and enhancing soil biology. Manure-based composts show relatively high plant nutrient levels compared to other types of compost products potentially allowing for partial replacement of mineral fertiliser. But, nutrient supply from compost products is neither tailored and balanced for crop demand nor immediate, potentially resulting in nutrient deficiencies or imbalances if compost is the only nutrient source. With proper nutrient accounting however, the use of compost can result in reduced inorganic fertiliser usage, and monetary savings.

Compost use adds external carbon to the soil organic matter pool, enhancing all soil properties that are directly or indirectly affected by soil organic matter, e.g. aggregation, tilth, water infiltration, erodibility, cation exchange capacity, pH, microbial density and diversity. Compost use can help slow the decline of soil carbon levels, but high and regular applications are required to build soil carbon levels over time, which is highly dependent on soil and environmental conditions, and also on cropping and farm management aspects.