Volume 25, 111

Tropical Grasslands (1991) Volume 25, 111–118

Sustaining productive pastures in the tropics
6. Nitrogen fertilised grass pastures

J.K. TEITZEL¹, M.A. GILBERT² and R.T. COWAN³

Queensland Department of Primary Industries:
¹South Johnstone,
²Indooroppilly and
³Ipswich; Queensland, Australia

Abstract

Nitrogen fertilised pastures are being used more in high rainfall areas as part of both beef and dairy production systems. Because of their productivity at critical times of the year, they have useful roles in reducing stress on other pasture types and boosting production from groups of cattle to match specific market requirements. On properties where cool-dry season management is critical, higher and less seasonal production can be attained by applying N fertiliser to a seasonally responsive grass on the deeper soils. On predominantly poorly drained properties N application to grasses resistant to trampling on high country, allows stock reductions on low areas during the wet season. The application of 200–300 kg/ha N annually gave near optimum milk and beef production per hectare in areas with annual rainfall greater than 800–1000 mm. Disadvantages of N fertilised pastures are high capital outlays in fertiliser and stock. However, under present economic conditions N fertilizer has a role in increasing productivity and sustainability of tropical and sub-tropical property management systems. Use on special purpose pastures can lead to substantial gains in farm profitability.