Managing farm effluent

Effluent is the liquid waste created when milking sheds and animal yards are cleaned with water. It is a valuable resource – using effluent to irrigate the land reuses both nutrients and water. As effluent filters through the soil, physical, chemical and biological processes remove harmful bacteria.

There are regulations about how effluent is stored, managed and used. Effluent cannot be discharged into streams or rivers. Care must be taken when effluent is irrigated onto the land so that it does not contaminate groundwater. Care must also be taken during wet weather to avoid surface ponding and run-off into streams and rivers.

Having adequate storage ponds means farmers can choose when to irrigate. This makes best use of the water and nutrients during dry weather and/or plant growth and reduces the need to irrigate in wet weather.

Riparian planting on stream edges creates a natural filter for run-off water and sediment.

The Sustainable Dairying Water Accord is a set of national good-management practices that guide farmers to quality riparian management. It reported in 2019 that significant progress has been made with effluent planning and sustainable actions across New Zealand.

ROD McKINNON

We wanted to build the new feed pad, and the existing infrastructure that we had just was never going to be satisfactory to do what we wanted. So we actually decided we’d build a large storage pond. The benefits of having storage to me became apparent straight away. So we made it as large as possible, and it gave us the ability to have storage for a good 100 days of the year and then use the nutrients when the farm really needed it rather than spreading effluent when it didn’t need to happen. We have a bunker that separates the solids out, and then the liquid effluent goes into the pond and then we irrigate to probably almost half of our farm. And then we try to use that at times of the year when we’ve got soil moisture deficits, so through the summer or when we want to put effluent onto cropping ground and things like that.

Acknowledgements

Rod McKinnon
Drone footage of feed pad and effluent pond, Rod at effluent pond and Rod hooking up effluent spreader to quad bike filmed by AF Productions and Paul Sutherland Photography. Copyright Yardmaster.