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Published: 2006-12-05 00:00:00

Dairy farmers growing maize for silage can significantly reduce the amount they spend on fertiliser simply by planting their crop on their effluent block or using effluent instead of bagged fertiliser.

That’s the message Environment Waikato, Dexcel, Pioneer Brand Products, DHM Labs and Foundation for Arable Research are giving to farmers at a series of on farm field days.

Environment Waikato’s sustainable agriculture facilitator Gabrielle Kaufler said maize was deep rooting and required considerable amounts of nutrients, especially nitrogen and potassium.

“Effluent blocks are quite often overloaded with these two nutrients, so it makes sense to plant in these areas.”

In contrast, back paddocks usually have low soil fertility and require considerable amounts of fertiliser if used for growing maize. An alternative to applying bagged fertiliser is irrigating dairy shed effluent.

A trial underway on Mike Visser’s farm near Te Awamutu has shown he will save $450 per hectare per year by using some of his dairy shed effluent on his maize block. However, Ms Kaufler warned farmers need to be careful not to apply too much and create run-off to waterways.

“Farmers need to work out how much nitrogen and potassium their maize needs for optimum growth. They then need to regularly test their effluent so they know how much nitrogen, potassium and other nutrients it contains. Once they know their effluent’s nutrient value they can calculate how much they should be applying to their maize block.”

Under Environment Waikato’s Regional Plan, irrigating effluent to land is a permitted activity. This means farmers don’t need a resource consent, but they must follow certain rules. Some of these are:

  • not applying more than 25 millimetres per application to prevent run-off
  • applying a maximum of 150kg of nitrogen per hectare per year on pasture and 200kg of nitrogen per hectare per year on maize
  • ensuring their effluent doesn’t pond on the land surface or create any odour or discharge nuisance outside their property boundary.

Full and complete details of the rules for irrigating effluent to land can be obtained by calling Environment Waikato’s Resource Use Freephone 0800 800 402.

Farmers wanting more information about using effluent to fertilise their maize crops can attend field days on Alison and Russell Gibb’s farm at 127 Proctor Rd, Orini on December 6, Sue and Jim van der Poel’s Staarvon Farm in Hams Rd, Ohaupo on December 13, and David van Bysterveldt’s farm at 137 Roache Rd, Morrinsville on December 14.

The field days start at 10am and run to 12.30pm followed by lunch.