Although it's important for soils to have nitrogen for plant and grass growth, once nitrogen drains past root systems, it can become a pollutant. When the ground across paddocks becomes overly wet through rainfall or irrigation, the soil will reach a point where it can't hold water anymore. This happens because the air pockets within the soil become filled with water and will drain downward. During that process, nitrogen particles are carried with them to fresh waterways. This is called nitrogen leaching.

Nitrogen Leaching Environmental Initiatives

The New Zealand government's Freshwater Management policy requires councils to work with their regional farmlands to reduce nitrogen leaching. This is a great initiative, but it has also increased awareness of the potential environmental impacts of nitrogen leaching.

So what can we do to decrease leaching and reduce the risk of harsh chemicals in fresh waterways? We can look for natural solutions or alternative options to improve the health of your paddock soil and contribute to the overall health of our waterways. 

Ag Research is currently conducting a three-year study on ways to reduce nitrogen leaching called the Soil Armour Project funded by Sustainable Land Management and Climate Change program. In this particular study, they're applying hay across pieces of farmland for feed, but also to act as a sponge to nitrates from urine, fertilisers, and other excretions to reduce nitrogen leaching. 

As we've followed this study, we've been inspired to discover other natural solutions and alternatives for farmers to decrease nitrogen leaching on their own farmlands. From our knowledge of technical media applications for over 30 years, we understand how media affects soil.

Sawdust is one of those medias. It's a natural alternative that can work similarly to how hay is applied in the Soil Armour Project, but sawdust can offer other benefits to pastures and livestock.