Student project helps sustainable farming

Student project helps sustainable farming

26 May 2008

For many years, farmers have been spending significant - and increasing - amounts of money on fertiliser to increase pasture productivity on their farms, while at the same time having to better manage farm effluent.

Alan Gundrill, an Honours student from the Environmental Management and Ecology Department at La Trobe University Albury-Wodonga, has investigated the use of untreated dairy effluent for pasture improvement.

Through the generosity of a Kiewa Valley dairy farmer, Alan constructed 30 experimental plots, to which various combinations of effluent and inorganic fertiliser were applied. Soil cores were collected from the plots for analysis of key nutrients, while the pasture was cut, weighed and analysed for total yield and nutrient measurements. Through analysis of this data, Alan was able to review how much nutrient was utilised by the pasture and how much was lost via leaching through the soil or lost to the atmosphere.

"The key aim was to determine which particular combination produces the greatest yield of pasture in the most cost-effective manner. Fertiliser selection is very important, as effluent is generally high in nitrogen and phosphorus. Farmers should work with their local agronomists to ensure that fertilisers are only used to provide for what is not available in the effluent," stated Alan.

An interesting - though not unexpected – finding was that plots treated only with the "fresh" dairy effluent did not demonstrate the same spike in pasture growth as those treated with inorganic fertilizers.

"The fresh dairy effluent, with its high organic material content, appears to be acting more like a slow-release fertiliser, and would therefore be giving up its nutrients over time and also conditioning the soil in the process," explained Alan.

"We need further work on nutrient release from dairy effluent over time and under varying conditions to assist farmers with the development of more sophisticated strategies for short-term and long-term pasture growth and soil management," added Alan.

The Department of Primary Industries has been supportive of the project, providing funding for the pasture nutrient analysis.

"The findings of this applied science project could assist farmers to make better use of the effluent their animals produce, with the potential of making significant cost savings," said La Trobe Honours supervisor and lecturer, Roger Croome.

"The significant increase in fertilizer cost in recent times is likely to provide a greater incentive for many farmers to consider how they might best utilise the nutrients that are bound up in their farm effluent."

For further information on the project, please contact Dr Roger Croome on (02) 6024 9872.

To arrange an interview or for further information, please contact:

Reinhard Beissbarth
La Trobe University Albury-Wodonga
Phone: 02 6024 9874
Email: r.beissbarth@latrobe.edu.au

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