Alternative fertilizers field research project

This producer-initiated field-research project was a collaboration between Binalong Landcare, NSW Department of Primary Industries and Regional Development and South East Local Land Services. With the fluctuating cost of conventional fertilizers and concerns around environmental and long-term sustainability, producers were interested in comparing the performance of alternative fertilizers. They were particularly interested in knowing whether alternative fertilisers could in fact boost production in a cost effective way. Many alternative fertilizer products are marketed using anecdotal claims around their effectiveness so this project set out to validate product performance using a scientific approach. All products trialled were compared to both a nil control and single superphosphate treatment.

One of the key drivers of pasture growth from the fertilizers trialled is phosphorus. This response is in line with other pasture field research trials. The results have highlighted that the relative cost effectiveness of the products trialled have largely been determined by the plant availability of the phosphorus in each product as well as their pattern/frequency of application.

Some 140 landholders descended on the Bookham Hall on 1 September 2015 to hear the latest research on the use of Alternative Fertilizers for pasture and livestock production. The seminar saw the showcasing of six years of trial results from the project at Binalong and Bookham.

The seminar also featured presentations summarising the importance of phosphorus in running productive grazing systems as well as a foundation for determining the suitability of a range of alternative fertilizer/soil treatments for their own situation.

View videos of the presentations:

Native Pasture and Alternative Fertilizer Project - Summary of 6 years pasture, soil and economic results

Fiona Leech, South East Local Land Services, Yass

Livestock production resulting from the use of a range of alternative and conventional fertilizers

Phil Graham, NSW Department of Primary Industries and Regional Development, Yass

Phosphorus cycling in pasture grazing systems and importance of soil microbiology

Dr Alan Richardson, Soil Biologist, CSIRO

Key messages resulting from five alternative fertilizer field research projects in NSW

Dr Lewis Kahn, Agricultural Information and Monitoring Services, Armidale

Common questions around fertilizer use on pastures

Fiona Leech, South East Local Land Services, Yass

Further research

Further research occurred in the sixth year of the project where effects of the fertilisers on the soil microbial communities were measured. Molecular techniques using soil DNA collected under the various fertiliser treatments were used to investigate the diversity of soil microbial communities under the differing fertiliser regimes.

Key findings:

  1. The results showed minimal influence of alternative fertilisers on highly resilient soil microbial communities.
  2. Farmers should continue to use economic rationales associated with pasture productivity response to guide their decision making around the choice of fertilisers to apply.

Despite large differences in pasture growth across the various fertiliser treatments, there was no significant effect of the alternative fertiliser treatments on microbial community structure compared with either the superphosphate or unfertilised control treatments. The observed variation in bacterial, fungal and archaeal community structures across all fertiliser treatments was best explained by soil pH or aluminium concentration, which was influenced differentially by the fertiliser products. Fungal community structure was also correlated to pasture productivity parameters, that included pasture yield, clover percent and soil available P.

These findings demonstrate a highly resilient soil microbial community that was influenced minimally by use of the alternative fertiliser products. Soil microbial community analysis as a predictor of the productivity of a pasture system is currently not an informative and defined tool to aid on-farm decision making, and the overall findings of this study support this. It is worth noting, however, that for a small number of soil fungal groups a relationship was found to pasture productivity parameters, indicating that in the future it might be possible to identify specific indicator organisms that can be linked to higher or lower levels of pasture production. Understanding relationships between soil microorganisms and pasture production will none-the-less continue to be a significant challenge, given the complexity of the microbe-soil-plant interface.

The key conclusion of the work undertaken is, farmers should continue to use economic rationales associated with pasture productivity response to guide their decision making around the choice of fertilisers to apply. In doing so, they can be re-assured that they are not having a detrimental effect on the microbial communities that are present in the topsoil.

Research partners:

This research study was hosted and supported by Binalong Landcare, subgroup of Harden-Murrumburrah Landcare with trials conducted on properties owned by Bruce and Noeleen Hazell ‘Kia-Ora’ Bookham, Gary and Hansie Armour ‘Te Kooti’ Bookham and Old Bundemar Pty Ltd (former managers Geoff and Fiona Henderson) ‘Glenroy’. Funding was received from NSW DPIRD, former NSW

Department of Environment and Heritage, former Murrumbidgee Catchment Management Authority, the Australian Government’s National Landcare Program, Woolworths, NSW Local Land Services, Meat & Livestock Australia (E.PDS.1503 Final Report), Sibelco Australia, and Sheep Connect NSW.

More information:

Details of the research (Comparative effect of alternative fertilisers on pasture production, soil properties and soil microbial community structure) were recently published in CSIRO journal, Crop and Pasture Science,Volume 70 (12) 2019. Authors were ex NSW DPIRD Agronomist and now Yass based Local Land Services Senior Agricultural Adviser Fiona Leech, Dr. Alan Richardson CSIRO Agriculture & Food, Dr. Michael Kertesz University of Sydney, Beverley Orchard, formerly NSW DPIRD, Dr. Samiran Banerjee North Dakota State University, and Phillip Graham, formerly NSW DPIRD.

Results of the research are now available. Those interested can download the research manuscript and supporting materials for more information.

Fiona Leech
Senior Land Services Officer (Mixed Farming Systems)
South East Local Land Services
0427 201 805

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