Protecting agricultural soils

Protecting agricultural soils

Opinion piece: 

Queensland’s agricultural sector is concerned about growing challenges to the NSW Government’s MWOO decision, writes Georgina Davis, Queensland Farmers’ Federation CEO. 

Recent rhetoric from the waste management industry around the decision by the NSW Government to reaffirm it’s 2018 ban relating to the application of mixed waste organics output (MWOO) to agricultural land and forestry is disappointing. With a recent article even discussing opportunities to challenge the decision through a merit appeal or other legal challenge.

The number of individuals who consider agricultural land to be a dumping ground for stabilised municipal waste (including MWOO) is unacceptable; all to simply avoid landfill tax and operational costs associated with source separation, resource recovery, treatment and appropriate disposal to engineered, licensed facilities where required.

Queensland Farmers’ Federation (QFF) has been actively advocating to the Queensland Government to ban the application of stabilised municipal solid waste to farmland for some years.

Currently, mixed waste compost is applied to farmland in Queensland using AS4454 (Australian Standard for Composts, Soil Conditioners and Mulches) to provide a suitable threshold.

AS4454 is limited, and at best, only infers minimum quality standards. It does not contain criteria for new and emerging contaminants such as PFOS and PFOA and the physical contaminant levels still permit significant levels of contamination [for plastics (soft) (<0.05 per cent dry matter w/w – visible proportion only) and glass, metals and rigid plastics (<0.5 per cent dry matter w/w)].

Many jurisdictions have suffered an early ‘shred and spread’ application of municipal wastes and untreated organics to land, which were driven by the desire to avoid increasing waste disposal charges, often as a result of a landfill tax.

In these cases, many environmental regulatory authorities were slow to realise the loopholes, determine environmental harm, and in turn, control application or specify application rates.

Application rates were decided by farmers and in some cases, the market value (or free of charge nature) of these products against the increasing price of traditional chemical fertilisers or quality organic products.

Early applications of stabilised waste/mixed waste composts to UK farmland in the late 1990’s to early noughties (to avoid the landfill tax) were dealt with through a judicial process.

This was a result of Her Majesty’s Revenue and Customs seeking to recover significant sums of outstanding landfill tax or contractual breaches between local government, contractors and landholders. In some cases the judicial actions were to recover funds to remediate the land.

Fortunately for the UK an exemption for stabilised waste from the landfill tax was never granted, and the growing demand from continental Europe for refuse derived fuels (RDF) resulted in many MBT/BMT plants being converted to RDF/SRF manufacturing facilities.

Areas of the United States and Europe have seen ongoing concern and opposition to the spreading of mixed waste composts, compost-like organics (CLOs), stabilised wastes, manures and untreated biosolids to land, in particular to farmland.

This has resulted in some jurisdictions setting high quality standards for both organic waste treatment processes and the resulting organic products and land/plant application limits. While others have always simply banned the application of mixed waste composts and CLOs to farmland.

One issue is that it is easier to define and prove environmental benefit than environmental harm, particularly where the application soils are weak, degraded or deficient in a range of nutrients or organic matter.

As such, mixed waste composts and CLOs in many cases easily demonstrate their beneficial application, sometimes in preference to single stream (green waste) composts; whilst the contamination risks are harder to define and more expensive to prove.

This is particularly true for the cost of analysis to identify micro-pollutants and the required commitment of undertaking longitudinal surveys to determine the risks of bioaccumulation in soils and plants, or retardation of plant growth.

Recently in the UK, there has been an outpouring of public and political concern regarding the environmental impacts resulting from the application of green waste composts manufactured from source segregated (domestic) waste streams to farmland.

Concerns regarding the land application of these products include the impacts of physical pollutants such as plastics, biological factors including pathogens and genetically modified organisms, animal diseases, the toxicity from heavy metals; and more recently as highlighted in the literature, the bioaccumulation of persistent organic pollutants and micro-pollutants.

The UK’s PAS 100 standard for example, allows 0.12 per cent of plastic in a final composted product – the equivalent of 1.2 tonnes of plastic in 1000 tonnes of compost. However, continued analysis has shown that the level of plastic contamination is rising in the UK, with the Scottish Environmental Protection Agency and the Environment Agency England, now introducing a 50 per cent reduction in the allowable (not desirable) level.

There is also an assumption by many that applying MWOO or CLO’s to forestry or pasture presents a ‘lower risk’.

While that land may be used only for forestry or pasture now, the changing climate, changing hydraulic characteristics of water catchments (with some areas seeing more or less precipitation); and more pressure to grow food for domestic and export markets, coupled with restrictions on clearing undeveloped land (Vegetation Management legislation in Queensland for example); it is increasingly likely that new land for growing food may utilise existing timber and foliage production areas or pastoral properties.

Once soils are contaminated it will be prohibitively costly and technologically challenging to remediate them.

The manufacture of MWOO and CLOs also poses a risk to the viability and sustainability of the organic recovery/composting sector.

Queensland’s agricultural sector needs a vibrant and healthy organic manufacturing sector capable of supplying quality soil and potting mixes through to contaminant-free compost and mulching materials for tree crops.

While many farms produce their own organic products, the quantities are insufficient to meet all of agriculture’s needs and many primary producers do not have the physical land footprint, appropriate location, infrastructure capacity, feedstocks or ‘want’ to manufacture their own organic products.

Land and soils are precious. Some farmland is genuinely irreplaceable and critical to ensure future food and nutrient security for our communities. There is also a growing consumer expectation and requirement for transparency and traceability surrounding the food chain.

Queensland, and indeed Australia, is a significant exporter of quality produce, and as such, it is imperative that Queensland maintains the quality of its farmland and food chain production standards.

For 2019–20, the total value of Queensland’s primary industry commodities (combined gross value of production and first-stage processing) is forecast to be $17.80 billion. And the gross value of production (GVP) of Queensland’s primary industry commodities at the ‘farm gate’ is forecast to be $13.94 billion; noting a considerable reduction on previous years due to climate impacts including the ongoing drought.

Any activity perceived (not necessarily proven) to contaminate farmland would damage our reputation and demand for our primary produce. Domestic consumers are also quite rightly questioning the provenance of their food.  They want to know animal husbandry conditions and where their carrots were grown down to the farm, the paddock and the soil type.

QFF supports a precautionary principle and science-based decision-making, acknowledging the deficit of credible and valid scientific data concerning many of the emerging contaminants and their end of life outcomes in the environment.

Farmers are custodians of the land and they want to be confident that the soil ameliorants they are using do not pose any negative environmental or health impacts.

QFF will continue to advocate for clear policy concerning the permitted end-uses for stabilised non-source segregated municipal solid waste and CLOs that does not include application to agricultural land; and will continue to promote quality composts, mulches and soil ameliorant products to the agricultural sector.

Georgina Davis is the Founder of consultancy firm The Waste to Opportunity Enterprise and Adjunct at the Australian Rivers Institute, Griffith University.

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