DAIRYBAL - a whole of farm nutrient and water mass balance spreadsheet

The dairy industry now has access to a computer program that will enable better management of the nutrients in the waste produced by dairy farms.

DAIRYBAL is a dairy waste management spreadsheet model designed to help producers sustainably manage their waste to ensure maximum dollar returns while protecting the natural resources upon which their livelihoods depend.

Part of a complete package

DAIRYBAL was developed by DPI&F's intensive livestock environmental management engineers and scientists. It is available as a stand-alone spreadsheet and has also been incorporated in the Dairying Better n' Better CD which is a Knowledge Based Decision Support System (KBDSS) developed through the Dairying Better n' Better project. The CD is a web-style information manual for subtropical dairy farms, providing guidance for more profitable and environmentally sustainable farm management, focusing on better practices for irrigation, fertiliser, soil and effluent management.

Guiding farmers to ensure a sustainable future

DAIRYBAL may be used to estimate the nutrients in dairy farm waste and to apportion the nutrients across the farm. Consequently, it is a useful tool for managing the reuse of effluent and manure as an organic fertiliser and for assessing the sustainability of grazing practices.

This information can then be used to estimate inorganic fertiliser requirements to supplement effluent/manure applications. This could potentially result in significant fertiliser cost savings while protecting the environment.

DAIRYBAL can also be used to estimate the size of the effluent ponds required to treat the inflow from milking sheds and yards, and to store effluent, pending irrigation onto crop or pasture. Where feedpads are used, the spreadsheet can also estimate the required size for retention ponds to catch contaminated runoff.

Recommendations specific for your region

In developing DAIRYBAL, climatic data has been included for twenty dairying regions throughout Queensland and northern New South Wales. By simply selecting a region, the user can obtain recommendations specifically for that area.

Model overview

The model uses the Digestibility Approximation of Manure Production (DAMP) and mass balance principles to determine the waste output of a dairy herd from the rations fed to the cattle and the pastures and/or forage crops grazed.

The waste is then apportioned between the milking shed, yards, feed pad and up to 6 individual paddocks. The resulting liquid effluent and solid wastes may then be applied to any of these paddock areas.

The model performs a nutrient mass balance on the waste application areas to determine whether the proposed cropping or pasture management practices on these areas are environmentally sustainable in terms of nutrient loading. Any nutrient shortfall can then be supplemented with inorganic fertilisers.

DAIRYBAL also assesses effluent treatment and storage requirements and includes a water balance to determine required secondary effluent storage pond volumes to achieve an acceptable pond spill frequency.

For more information about DAIRYBAL

Alan Skerman
Senior Environmental Engineer
Department of Primary Industries and Fisheries
Phone: +61 7 4688 1247
Email: alan.skerman@dpi.qld.gov.au

Last updated 28 June 2004