Getting Smart with Nutrients

Minimising losses
to protect waterways
Stuart Edmeades sees nutrient
contamination of water as a key issue for
the area around Putaruru, since water is a
valuable local resource. He is determined
to minimise the loss of nutrients from his
own 165 ha dairy farming operation to
protect ground water and the crystal clear
Waihou River.
“Dairyshed effluent is a huge problem
- we generate 22,000 litres of it each
milking time with our rotary shed. I don’t
want to see that run off into our river. And
I am concerned about nitrogen because our
ground water is very shallow. Water from
Putaruru is bottled and sold because it is
so pure, and we have to keep it that way.”
Stuart had an effluent irrigation system
which was deemed adequate for his
conditions, but his own observations led
him to doubt its effectiveness. “We were
spreading over the recommended area, but
found it was still running off in a wet year.
So we put in another kilometre of piping
and added 35 hectares to the 25 hectares
we could already spread on. Even though
it’s pumice, the soil seemed to be sealing
off, so now we plan to alternate four years
on, four years off on the different areas
to avoid runoff.”
As Chairman of the Te Waihou Walkway
Committee, Stuart feels he needs to set a
good example on his own farm which has
over 3 km of river frontage and sees many
visitors each year appreciating the
sparkling waters of the spring-fed upper
Waihou. “Years ago, before the river was
fenced, I used to watch 250 cows get into
the river and as soon as they started to
move, it would turn green. Now when I
see any effluent reaching the water it
upsets me.”
To avoid the possibility of effluent spills
contaminating the river, Stuart has a series
of backstops to his effluent system. A new
float switch has been fitted to the holding
tank to prevent leaks. Stuart has created
a wetland in a nearby gully so that any
accidental effluent overflow can
collect rather than flow straight to
the stream below. He has also
created a pond as an additional
pollution trap, and fenced off grassy
filter strips beside the stream
where it joins the Waihou River.
Other farmers in the district are also
fencing and planting areas along the
main river and its side streams. “The
main benefit is to fence and prevent
stock going in so the nutrients stay
on the land, not in the water.”
Stuart is also mindful of efficient
nutrient application on the farm,
working to a ten year strategic plan
prepared by his brother, a fertiliser
consultant and soil scientist. “We calculate
that by keeping careful track and only
putting on what is needed, we have saved
$120,000 over standard practice, and we
are only five years into our plan.”
Stuart Edmeades
Environmental Benefits
✔ Fertiliser use is based on nutrient budgeting and
professional advice, helping to reduce waste and potential
for losses to groundwater and waterways.
✔ Nutrients from farm dairy effluent are recycled back to
paddocks using well-managed irrigation to prevent
surface runoff.
✔ Nutrient losses to waterways reduced by careful fertiliser
application and using wetlands and fenced grass margins
beside waterways as filters.