Nutrient recycling on humanity's menu

Some ways we could do this:

• A national strategy for capturing and recycling nutrients in urban sewage treatment plants into fertilisers and soil amendments,
• A campaign to recycle or compost waste food in the catering industry and homes and a ban on sending food to landfill,
• The development of algae farms and other advanced bioprocessing techniques for reprocessing waste into fertilisers, biofuels, stockfeed, fine chemicals, bioplastics and so on,
• Wider on-farm use of perennial crops, deep-rooted crops, agroforestry and strip-farming techniques to intercept nutrients in groundwater and recycle them into timber, particle board, fruit, charcoal, flowers, bio-pharmaceuticals, fodder and stockfeed, electricity and biofuels,
• Use of instream aquaculture and algae culture to harvest nutrients in rivers, reservoirs and lagoons,
• The creation of farmable wetlands to harvest nutrients from surface run-off and convert them to aquatic crops of economic value,
• Design standards for farms, roads, buildings, urban developments and so on that minimise nutrient losses and allow for capture and reuse,
• Strategies for remobilising or phyto-mining nutrients trapped in aquatic sediments,
• Bio-farming using tailored suites of soil micro-flora and micro-fauna to mobilise trapped nutrients and increase their availability to crops and pastures,
• Harvesting of algal blooms in lagoons and estuaries and reprocessing them,
• Breeding of less nutrient-dependent crop and pasture cultivars,
• Research into organic farming methods to identify those with proven potential to conserve, recycle and mobilise nutrients,
• Development of extensive marine grazing systems that enable sustainable wild harvest of fish, shellfish and algae inshore to recapture nutrients, and
• Public education on the importance of nutrient conservation.

Above all, we need a national scientific plan and an attitudinal shift from our culture of waste. We recycle aluminium cans, steel cars, plastic containers, glass and paper. Why do we hardly reuse nutrients? To do so would undoubtedly save and make money. The additional food exports alone could earn an extra $25 billion to $50 billion a year.

There is an epic scientific challenge in this and Australian scientists - strong in agriculture, soil science, biotechnology and natural resource management - are well equipped to tackle it.

Solve the challenge of nutrient reuse and Australia may just help humanity pass the population peak into a managed decline instead of the catastrophic collapse that is the usual fate of species whose populations have outrun their resources.