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Focus on effluent solutions

Tuesday 19 October 2010, 11:36AM

By Waikato Regional Council

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WAIKATO

The dairy industry and Environment Waikato are implementing a range of actions aimed at helping improve compliance with effluent management rules, says the latest edition of Environment Waikato’s Farmcare publication.

In comments about recent publicity on a rise in significant non-compliance during the 2009-10 season, environmental farming systems programme manager Alan Campbell notes actions to address the problem include:

· circulating a checklist to farmers to help them evaluate their effluent systems
· releasing an effluent storage calculator to help farmers design a key component of their system
· finalising a code of practice for effluent system design.

“Developing these solutions takes considerable time and effort, mostly behind the scenes, and involves close working relationships between the council, DairyNZ, Federated Farmers, dairy companies and researchers,” Mr Campbell writes.

“Other examples of partnerships with these agencies include joint workshops and field days, which have been running for several years. On top of regular effluent management workshops, a special workshop on effluent storage is being planned for this season.”

Mr Campbell also says that, following the Waikato agricultural summits held over the last two years, the council is actively working with all sectors of the agriculture industry to develop tools and information that support the work that farmers are doing to improve their sustainability.

“These kinds of initiatives will help ensure the industry continues to adapt and adjust to current and future community expectations.”

Farmcare also highlights how getting effluent storage right is essential for farmers to comply with effluent management rules and protect the environment.

There are two main reasons why farmers need adequate effluent storage: the first is to allow for mechanical issues such as pump or irrigator breakdowns; the second is to take account of those times when soil may be too wet to absorb effluent.

“With a small storage capacity, there are few choices when the weather turns to custard or the pump fails,” writes proactive monitoring programme manager Ross Wightman.

“Any sump overflows or irrigation to saturated paddocks is a breach of Environment Waikato’s rules. Having sufficient storage is critical.”

Mr Wightman says that industry guidelines recommend three months storage capacity but adds that no two farms are the same and a one-size-fits-all approach may not always work. “Storage needs depend on factors such as rainfall, soil type, effluent systems, and the area of yards.”

To help farmers get their storage systems right, Environment Waikato is working with Massey University to develop a pond storage calculator. The calculator, which will be launched later this year, will allow farmers to enter their individual farm details such as square metres of yards, sheds and feedpads flowing into the effluent system, volume of water used daily on the yard, existing pond dimensions, soil type and irrigation discharge depth.

Another effluent management tool involves using effluent to grow maize and help rebalance soil nutrients.

“September to October is the ideal time for sowing maize for stock feed, so farmers will need to be quick if they haven’t already planted this year,” writes environmental farming systems advisor Kate Ody.

She says paddocks that have had effluent applied long term will already have high soil nutrient levels and are great for growing maize without the need for costly fertiliser.

“Growing maize on these paddocks will also reduce the ability of nitrogen to leach to groundwater and will use soil reserves of phosphates and potassium to bring soil levels back into the optimum ranges required to produce pasture in the future.

“Where maize is to be grown on less fertile land, applying effluent to the crop cuts fertiliser requirements and reduces potential for over application on to effluent blocks,” Ms Ody says.

Trial work carried out by the Foundation for Arable Research shows no significant yield difference in maize production between fertilised plots and effluent plots.

“If maize is to be an ongoing part of farming systems, paddocks used for growing should be regularly soil tested to establish nutrient requirements. Effluent testing will also allow an accurate nutrient budget to be prepared. The maximum permitted annual loading of nitrogen from effluent to maize crops in the Waikato without a consent is 200 kilograms of nitrogen per hectare.”