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Nitrogen fertiliser may pay on tropical grass pastures

Lawrence, D., Buck, S. R., Chudleigh, F., Johnson, B. and Peck, G. (2015) Nitrogen fertiliser may pay on tropical grass pastures. In: 17th Australian Agronomy Conference, 20-24 September 2015, Hobart, Tasmania.

PDF (Nitrogen fertiliser may pay on tropical grass pastures)

Publisher URL: http://agronomyaustraliaproceedings.org/images/sampledata/ASA17ConferenceProceedings2015.pdf


Low productivity in sown grass pastures due to a lack of available soil nitrogen can reduce beef production by up to 50% across Queensland. The feasibility of strategic nitrogen (N) fertiliser applications to address these losses was assessed by desktop analyses using data from published studies, local fertiliser trials and expert opinion. These analyses suggest that applying nitrogen to rundown sown grass pastures can produce dramatic increases in dry matter yield and animal production. However, high and consistent response rates in pasture productivity, stocking rates and growth rate of cattle were required for the application of nitrogen fertiliser to be profitable. For the suggested 100 kg N/ha fertiliser rate: average gross margins in the year of application were calculated to increase by 121-217% when dry matter yield responses of 40 kg DM/kg N (i.e. an additional 4000 kg/ha) and an additional liveweight gain of 0.2 kg per adult equivalent (AE)/day can be achieved (i.e. an extra 70 kg AE/year). These economics were very sensitive to the assumed response rates in pasture growth, stocking rate and liveweight gain and did not account for uncertainty in climate and beef
prices. New research is proposed to re-assess the responses used in this analysis that are largely based on research 25-40 years ago when soils were generally more fertile and pastures less rundown.

Item Type:Conference or Workshop Item (Paper)
Business groups:Crop and Food Science
Keywords:Sown pasture degradation, sown pasture rundown, nitrogen, dry matter production
Subjects:Agriculture > Agriculture (General) > Methods and systems of culture. Cropping systems
Plant culture > Field crops > Forage crops. Feed crops
Live Archive:06 Apr 2017 04:09
Last Modified:01 Dec 2022 00:39

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