CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Animal Production Science   
Animal Production Science
Journal Banner
  Food, fibre and pharmaceuticals from animals
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Structure
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Virtual Issues
Sample Issue
For Authors
General Information
Submit Article
Author Instructions
Open Access
Awards and Prizes
For Referees
Referee Guidelines
Review an Article
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates
Library Recommendation

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter logo LinkedIn


Article     |     Next >>   Contents Vol 41(3)

Nitrogen supply and demand in Australian agriculture

J. F. Angus

Australian Journal of Experimental Agriculture 41(3) 277 - 288
Published: 2001


The supply of and demand for nitrogen by whole industries and individual crops is discussed in relation to changes in farming systems, particularly the relative importance of fertiliser and biologically fixed nitrogen. The use of fertiliser nitrogen (N) in Australia has grown at an annual rate of 14% since the early 1990s, after growing at half that rate since the 1950s. The accelerated growth occurred during a period when world demand has been almost constant. Most of the additional demand has been for the dryland cereal and canola industries of southern Australia, where crops previously obtained almost all their N from mineralisation of soil organic matter and the residues of legume pastures. The most likely reasons for the belated increase in use of fertiliser N in Australia are to replace the supply from pasture residues as the area of pasture decreased and to satisfy the increased demand of cereals following break crops and of the break crops themselves, particularly canola.

For a dryland cereal, there is a problem of matching soil N supply with an unpredictable N demand. For winter cereals in Australia, crop N demand is poorly synchronised with soil N supply. The time of greatest demand is normally during the stem-elongation phase when the crop is growing fastest. For crops targeted for high-protein grain, there is an even greater demand around the flowering phase. The peak N demand for well-managed crops growing with no water limitations exceeds the capacity of the soil to supply N from mineralisation at the time, so additional N is required to meet the shortfall, either from fertiliser or mineral N retained in the soil from earlier mineralisation. Predicting the optimum supply of fertiliser N at sowing is difficult in cases where N demand is influenced by variable rainfall. Topdressing and banding fertiliser offer prospects for more closely matching N supply and demand for dryland crops. The future role of legumes in supplying residual N is discussed in relation to the trend towards continuous cropping.

Keywords: fertiliser, biological nitrogen fixation, mineralisation, nitrogen budget.

Full text doi:10.1071/EA00141

© CSIRO 2001

blank image
Subscriber Login

PDF (272 KB) $25
 Export Citation

Legal & Privacy | Contact Us | Help


© CSIRO 1996-2016