As in other parts of Victoria and Australia, dairy herd sizes have been increasing for many years in Gippsland, allied with improvements in dairies, tracks and pastures. However, in many cases improvements in effluent management have not kept pace with these changes. The result on many farms has been the wastage of good, productive land at the disposal site through waterlogging and nutrient overload, the potential for off-farm pollution, and the wastage of nutrients and organic matter which could be productively used on the farm.

Introduction

The proper management of dairy shed effluent is important as it is rich in nutrients such as nitrogen, potassium and phosphorus and contains large numbers of bacteria. For these reasons dairy shed effluent is potentially both very useful and harmful. Excess nutrients and bacteria (from a range of sources) in creeks and rivers is a problem in Gippsland as many towns take their water supply from local streams. The region's major river systems, the Avon, Latrobe, Macalister, Mitchell, Tambo and Thomson, empty into the Gippsland Lakes, an important area for tourism and nature conservation.

Dairy farm effluent systems have evolved from a shovel and manure pile alongside the old walk-through dairy in the 50s, to options which emphasise the collection, storage and recycling of nutrients to pastures and crops.

Despite these advances, many farms have continued to run effluent to a gully or hillside where it can cause problems. As you drive around Gippsland you can see many examples of effluent management systems that aren't working properly. Dark green lines running across paddocks and onto roads or into drains and creeks, or paddocks covered in brown liquid and weeds are tell-tale signs that there is still some way to go to achieve the goal of containing all the effluent on the farm and recycling nutrients back to pasture.

Effluent systems for Gippsland

Although Gippsland is only a small part of Victoria, there is great diversity of dairy farm situations and farmer management styles. Hence, the options suitable for different districts within Gippsland and individual farms vary widely.

Over 60% of Gippsland dairy farms depend on rainfall for their productivity. Rainfall is high, ranging between 900 and 1500 mm per year. Areas such as the Strzeleckis also have very steep hills with a large number of flowing gullies and creeks in the winter and spring. Areas such as Trafalgar and Longwarry have poorly drained flats with high water tables in winter. High rainfall, high watertables and steep terrain may make the construction of ponds of adequate size to hold effluent over the winter and spring months very difficult. Steep terrain may also make desludging ponds difficult and expensive. A small sump or pond and regular application of effluent to pasture via a travelling irrigator may be more feasible in such areas, particularly where soils are highly absorbent as in the Warragul district.

In areas like Yarram where rainfall is not as high but groundwater is available, farmers are tending to install spray irrigation systems to give added feed security. Usually, such country is flat or undulating and pond construction and maintenance is quite feasible. A very good option in this situation may be to store effluent over the winter and spring and pump it through the irrigation sprays over the drier months.

In the Macalister Irrigation District dairy farmers depend mostly on flood irrigation but an increasing number are also installing spray irrigation systems. The land is relatively flat, rainfall is low and pond construction and desludging is usually inexpensive and simple. In this area effluent storage ponds are probably the best option, with effluent being spread with flood irrigation water in the warmer months.

Farms on the Snowy River flats at Orbost (and to a lesser extent on the Macalister Irrigation District and elsewhere) are unusual in that they are subject to periodic inundation from the flooded river. Ponds are probably not a good option in this situation but direct spreading of effluent via a travelling irrigator should meet requirements quite well.

Demonstration sites

There are two dairy effluent systems that have been installed for demonstration purposes in Gippsland. A number of others exist in other parts of the state.

A two pond system has been installed on the Macalister Research Farm at Maffra. Effluent is stored over the winter and spring months and water from the second pond is gravity fed or pumped to an irrigation channel for spreading over 23 ha of laser levelled flood irrigation bays. Irrigation water reuse ponds have been installed at the bottom of the bays to ensure that no waste leaves the property via drains. It is envisaged that as the dairy herd increases, water from the second pond can also be used to flood wash the yards. This system can be viewed by appointment with the share farmer or with Ken Slee of DPI Victoria.

A second demonstration is located on the farm of Kerrie and Peter McLaren at Krowera in South Gippsland. This system is in steep, high rainfall dairy country in the catchment of a town water supply reservoir. Twin ponds have been installed and water from the second pond is recycled to hose-wash the yards. A pipe also siphons water from the second pond so that it can be spread onto pasture via a spray pot sprinkler. This demonstration system can be viewed by contacting the McLarens, Martin Fuller (the local Landcare officer) on 056 743516 or David Shambrook of DPI at Leongatha.

Other good examples of a wide range of options for managing dairy shed effluent are located throughout Gippsland and information on these may be obtained from Ken Slee, David Shambrook or Colin Waters (contact numbers listed below).

DPI Contact/Services Available

Traralgon: 03 51761 744

Further References

DPI Website: Dairy Effluent Agnote Series:

http://www.dpi.vic.gov.au

Information Notes Series – Livestock & Animals – Dairy /Effluent Management

ISSN 1329-8062

Published and Authorised by:
Department of Primary Industries
1 Spring Street
Melbourne, Victoria

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