Litter research could boost poultry producer income, reduce carbon footprint

No industry, no matter how high its reputation can afford to stand still, and waste products are amongst the first to come under scrutiny when an industry’s environmental credentials are examined. In the case of poultry production, using litter as fertilizer is a long-established practice. Yet re-use as fertilizer is not without its problems.

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The research aims to add value to litter making at a more valuable ingredient in fertilizer.
The research aims to add value to litter making at a more valuable ingredient in fertilizer.

Poultry production may already have a low carbon footprint, but the pressures from environmental legislation will undoubtedly increase.

No industry, no matter how high its reputation, can afford to stand still. Waste products are among the first to come under scrutiny when an industry’s environmental credentials are examined. In the case of poultry production, using litter as fertilizer is a long-established practice. Yet re-use as fertilizer is not without its problems.

Spent poultry litter is bulky, and concerns over its environmental impact can limit how much can be used. In addition, it is commonly perceived as having an inconsistent nutrient content. All these factors limit its use and its value. 

Litter could become an increasing problem for the industry. In some parts of the world, its local use as fertilizer is already reaching a point where the environment can take no more. This is holding back growth of poultry production. With demand for meat forecast to rise, without new methods for its treatment and use, litter could be the stumbling block to the industry reaching its full potential.

Can do better

Given the above, unsurprisingly, work is being done to make better use of spent litter ranging from using it as fuel to improving its value as a fertilizer. From a purely economic point of view, turning what was once considered waste, with its associated costs for disposal, into a valuable commodity is good for the bottom line. 

One such project is being run in Australia by Poultry CRC researcher Dr. Matthew Redding at the Department of Employment, Economic Development and Innovation. 

Redding is looking at value-adding strategies that minimize nutrient losses to the environment when litter is used at fertilizer, while providing better nutrient supply characteristics than traditional fertilizer. In the Australian context, there is no issue with disposal, yet the cost of disposing of litter is rising and often bound by legislative requirements. Poultry producers need to turn litter from being a cost generator to an income stream. 

Smart sorbers

Started back in late 2010, work has focused on incorporating bentonite and other “smart sorbers,” or synthetic clays, into litter. So far, the work has resulted in a number of benefits, including some beyond the researchers’ initial remit.

Redding comments: “Any material like spent litter, where your nitrogen and phosphorus are in organic forms, rather than inorganic, has the potential to be a good base for superior fertilizer, where loss to the environment can be minimized.”

The research team has identified a number of possible approaches to improving the quality of spent litter. 

One approach would be to consider the addition of spent litter with smart sorber to a more complete fertilizer formulation, including the addition of inorganic phosphorus, for example, at a rate of up to 20 percent of total phosphorus. This approach could offer the benefit of a balanced and tailored fertilizer product that would increase its marketability. 

Another option might be to increase the initial application rates of spent litter smart sorber combination. This would avoid the phosphorus losses that would occur with a large single application of inorganic phosphorus. 

Alternatively, a lower amount of smart sorber could be included in litter, thereby lowering production costs. Preliminary experiments have shown that inclusion rates of between 10 and 20 percent on a dry mass basis would be sufficient to reduce phosphorus losses.

Additional benefits

According to Redding, putting bentonite into the poultry shed, either to improve currently used conventional bedding materials, or as a partial or full replacement for these materials, would offset the cost of purchasing it in the fertilizer by reducing costs in bedding, but it could also result in improved bird performance. 

The added benefit resulting from including smart sorbers into poultry bedding was improved bird performance. Laboratory volatilization trials indicated that when bentonite is used as a bedding material in combination with spent wood shavings-based litter, ammonia volatalization decreases relative to spent litter alone. If applied in shed, there could be an improvement in air quality and hence bird productivity.

Poultry manure contains all of the 13 essential nutrients that are used by plants and, once the research is complete, scheduled mid-2016, its application may give poultry producers a market-ready resource that can reduce overall farm costs and have a positive environmental impact.

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