Decisions used by NSW grains industry advisers to determine nitrogen fertiliser management recommendations

2016

Research organisaton
Funding source

Trial details

Researcher(s) Luke Beange (NSW DPI)
John Cameron (Independent Consultants Australia Network)
Graeme Schwenke (NSW DPI)
Year(s) 2016
Contributor Department of Primary Industries NSW
Trial location(s) Tamworth Agricultural Institute, NSW
Further information View external link
Decisions used by NSW grains industry advisers to determine nitrogen fertiliser management recommendations locations
Aims

Toreport on decisions used by NSW grains industry advisers to determine nitrogen fertiliser management recommendations.

Key messages

Key findings:

  • Nitrogen (N) decision making requires a good understanding of background soil and plant science, and soil test interpretation.
  • Training for new agronomists needs to be a priority issue.
  • Senior NSW agronomists identified crop yield expectation as guided by soil moisture at sowing (or at the time of N decision making) as the most important determinant of N fertiliser requirement.
  • Further research is needed to increase the understanding of how management practices affect potentially large gaseous N losses. 
  • Changing from legume pasture-crop sequences to continuous cropping in many central and southern areas of New South Wales is posing new questions for managing N supply. The absence of N-fixation by pasture legumes is seen as a substantial loss of N-buffering capacity.
  • Despite most advisers choosing soil testing as a key approach for determining N fertiliser required, many of their clients had a lower confidence in soil testing, citing ‘high perceived variability in soil nitrate results in the lead up to sowing’.
  • Conclusions and Recommendations

    Senior advisers highlighted the importance of quality training in N decision-making, understanding the background soil and plant science involved, and soil test interpretation for the next generation of agronomists, with training courses including representation from highly experienced local agronomists.
  • The understanding of gaseous N losses requires further research, development and extension to the grains industry. Recent field research in the north was limited in scope and produced challenging outcomes that can potentially lead to large practice changes in when and how N fertiliser is applied. Further research and development work is warranted to answer more of the practical questions growers and advisers are asking in regards to losses associated with various alternative practices.
  • The northern results on N loss pathways are less relevant to advisers in the central and southern regions where N application timing, soil type and climatic differences are generally quite different from the dominant medium-heavy clays of the north. New N loss research is recommended for the lighter textured soils in regards to the potential for N volatilization losses from surface N application of various products. Economic outcomes from the various strategies being practiced are also needed. Nitrogen loss research should focus less on expensive slow-release products and more on optimising results from urea, the cheapest N source.

  • Research into better soil water measurement was seen as a priority area, especially given the importance all advisers place on knowing this when making expensive N-fertiliser decisions for a coming cropping season. Zonal management within paddocks is not possible with single site characterisations, so atypical areas of paddocks are over or under-fertilised.

  • The very early application of N fertiliser ahead of a winter cropping season is well established, but what is not known is how well the subsoil N may be protected or at risk from denitrification in flooding events. Also, better knowledge on specific N use within the profile during the cropping season will help growers to know when late-applied N is likely to be inaccessible to crop use.

  • Nitrogen mineralisation was highlighted by agronomists from all three regions as an area for greater understanding with regards to the differences caused by climatic conditions, especially rainfall. They also require better understanding of the N produced from both native organic matter and recent legume pasture residues.

  • There are a number of good decision support tools available currently, with several advisers suggesting that combining the best points of each into one package, even one available as an app, would be highly useful, particularly one with good grower-friendly reports.

  • Many farmers have low confidence in soil testing.  This may be related to a range of factors from poor sampling strategies, to poor sample handling, to poor service from laboratory analysts, to insufficient sample numbers or poor interpretation of the results. It is seen as an expensive option for many, with some advisers looking for quicker and cheaper means of estimating soil mineral N.

  • Variety-specific N management packages were seen by some senior advisers as key areas for continued research funding, as results from some new varieties have been quite different in terms of N uptake and protein outcomes.

Lead research organisation Department of Primary Industries NSW
Host research organisation N/A
Trial funding source GRDC UQ00079
Related program N/A
Acknowledgments

This survey and follow-up interview series was part of the project Organic matter and nutrient availability (UQ00079), a collaborative project between state agencies and universities in Queensland, NSW, Victoria and Western Australia with joint investment by GRDC. Special thanks to Fiona Pearson (NSW DPI) for transcribing the hard copy surveys, to Georgia Rose and Erica McKay (ICAN) for collating the survey data and transcribing the interviews, and to Helen Squires (NSW DPI) for producing the map.


Other trial partners Not specified
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Method

Crop type None: No crop specified
Treatment type(s)
  • Farm operations: Other
Trial type Article/commentary
Trial design Not applicable

Tamworth Agricultural Institute 2016

Sow date Not specified
Harvest date Not specified
Plot size Not specified
Plot replication Not specified
Download the trial report to view additional method/treatment information
Trial source data and summary not available
Check the trial report PDF for trial results.
Observed trial site soil information
Trial site soil testing
Not specified
Soil conditions
Trial site Soil texture
Tamworth Agricultural Institute, NSW Not specified
Derived trial site soil information
Australian Soil Classification Source: ASRIS
Trial site Soil order
Tamworth Agricultural Institute, NSW Vertosol
Soil Moisture Source: BOM/ANU
Average amount of water stored in the soil profile during the year, estimated by the OzWALD model-data fusion system.
Year Tamworth Agricultural Institute NSW
2016 794.7mm
2015 788.3mm
2014 788.1mm
2013 780.3mm
2012 774.5mm
2011 772.8mm
2010 799.1mm
2009 784.3mm
2008 792.0mm
2007 788.5mm
2006 790.3mm
2005 797.4mm
2004 799.1mm
2003 800.0mm
2002 781.0mm
2001 777.0mm
2000 747.4mm
National soil grid Source: CSIRO/TERN
NOTE: National Soil Grid data is aggregated information for background information on the wider area
Actual soil values can vary significantly in a small area and the trial soil tests are the most relevant data where available

Soil properties

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Climate

Derived climate information

No observed climate data available for this trial.
Derived climate data is determined from trial site location and national weather sources.

Tamworth Agricultural Institute NSW

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Some data on this site is sourced from the Bureau of Meteorology

SILO weather estimates sourced from https://www.longpaddock.qld.gov.au/silo/
Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data , Environmental Modelling and Software, Vol 16/4, pp 309-330. DOI: 10.1016/S1364-8152(01)00008-1.

Trial report and links

2016 trial report



Trial last modified: 16-07-2019 13:44pm AEST