Transforming chicken manure into nutrient-rich fertilizer for crops

An international collaboration between researchers from Brazil and the United States has identified a process for turning poultry waste into a soil additive for agriculture.

“Several countries have large poultry production, especially United States and Brazil, where agriculture is also concentrated,” says Aline Leite, a Post Doctoral researcher from the Federal University of Lavras in Brazil. “So, reusing a global residue generated in large amounts is an interesting way of promoting a circular economy.”

The researchers harvested poultry manure from an experimental site in the United States, which they heated to turn into biochar, a carbon-rich substance that is used as a soil additive to replenish critical nutrients like phosphorus.

“We are focused on understanding mechanisms that are responsible for increasing phosphorus availability in materials like manure,” says Leite.

Poultry manure is full of calcium and requires higher temperature treatments to turn the waste into biochar, however, these higher temperatures can have an effect on the amount of phosphorus available.

In order to ensure that the biochar contained sufficient available phosphorus, the researchers enriched it with another mineral, magnesium, which protected the phosphorus from the heat and enabled it to form more soluble forms of phosphorus.

Using the IDEAS and VLS-PGM beamlines at the Canadian Light Source (CLS) at the University of Saskatchewan (USask), the researchers were able to visualize the connection between phosphorus and magnesium and confirm the success of their technique.

Their findings were recently published in the scientific journal, Chemosphere.

While phosphorus reserves are found across the globe, the nutrient is a finite resource. Finding ways to recycle the mineral is an important issue for scientists.

“There’s no excuse for not using the phosphorus that is already in the food chain, for example, by reusing the waste that is already generated,” says Leite.

Leite says that synchrotron technology is essential for research into agricultural applications.

Read more on the Canadian Light Source website

Recycling phosphorus from wastewater to grow better crops

Scientists are helping close the loop on the sustainability cycle with research into nutrient-enhanced biochar — a charcoal-like material made by heating recycled biomass in the absence of oxygen (a process called pyrolysis). Biomass is any living or once-living material – including plants, trees, and animal waste — that can be used as a source of energy.

Daniel Strawn, Professor of Environmental Soil Chemistry at the University of Idaho, and his colleagues are interested in enhancing biochar – which can be used as an amendment to promote soil health — by adding phosphorus, a crucial nutrient for crops.

The research team, which also included scientists from the University of Saskatchewan and Washington State University, has focused its efforts on recovering phosphorus from wastewater.

“Phosphorus is a limited resource, taken out of the ground, processed to produce fertilizer, and eventually it ends up in wastewater,” says Strawn. “We are developing technology to recover it using biochar in a water treatment process.”

Biochar is an effective sponge ­that can soak up phosphorous and other nutrients, like nitrogen, from waterways. The team is testing this treatment process on municipal and agricultural wastewater systems.

With the help of the Canadian Light Source (CLS) at USask, Strawn and his colleagues confirmed in a recent paper which type of phosphorous had been absorbed by the biochar — a crucial step to understanding and refining their process.

Read more on the CLS website