Radio Transcript

Welcome to Agritalk. 

This week we are going to be talking about using Dairy Effluent as fertiliser.

Recently there have been significant increases in the cost of fertiliser

This has highlighted the value of cow manure captured at the dairy shed/or dairy feed pad as viable alternative to fertiliser.

A monthly milking herd of 500 cows that spends up to 2.2hrs/day on areas draining to the effluent management system can produce up to $11,000 worth of fertiliser equivalents per year.  The 2.2 hrs/day relates to the herd being milked twice a day through a 50 unit rotary dairy. 

Rural Solutions SA utilises an Micro Soft Excel spreadsheet to determine the amount of cow manure captured at the dairy and/or feed pad, then converts the relevant nutrients in the cow manure to a fertiliser equivalent. 

The three main nutrients that are considered in the spreadsheet are nitrogen, phosphorous and potassium.  Therefore the weight of Nitrogen, Phosphorous and Potassium in the cow manure is compared to an equivalent synthetic fertiliser to determine a monetary value for the effluent.

Cow manure Nitrogen is compared to urea, Phosphorus to single superphosphate, and potassium to muriate of potash.

The weight of manure captured is a function of several variables, however the most relevant is how much time the herd spends on areas draining to the effluent management system. (i.e. in the dairy yard, or shed, or on the feed pad) 

For the most efficient results the effluent needs to be applied to actively growing crops/pastures. 

RSSA provides on-farm technical service to dairy farmers to improve their existing effluent management system, as well as designing new systems.

A new 60 unit rotary dairy and effluent management system has recently been installed on the Fox’s property near Allendale East.  The system was designed for 600 cows.

The property’s effluent management system comprises of a screw press separator, which separates the solid and liquid components of the raw effluent.  The separated liquid effluent is stored in a 54,000 litre open tank and recycled for yard washing.

A Williams travelling irrigator is used to distribute the surplus effluent to 40 hectares of dry land during the wetter months, and over 10 hectares of irrigated land during summer & autumn.

The separated solids are applied to dry land every two months using a conventional belt spreader. 

Ian Fox said 
“This year we were able to get a second cut of hay off the dry land paddock that was irrigated with effluent.  The late rains helped us, but I attribute it mostly to using the effluent,”.

In SA an on-ground works incentive scheme is available to SA dairy farmers. More information can be found on the SA dairy industry website. www.dairyindustrysa.com.au

For further information on this story or any edition of Agritalk, please visit www.ruralsolutions.sa.gov.au, click on news, then radio.  You will find a transcript of the program along with lots of handy links to the things discussed.

Information gratefully supplied by Michael O'Keefe, Livestock Consultant, Rural Solutions SA o'keefe.michael@saugov.sa.gov.au

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