Improving the efficiency, profitability and environmental friendliness of nitrogen fertilizers

Introduction

Nitrogen fertilizer efficiency is generally low; 30-70% even in intensively managed agricultural systems. Gaseous N losses, ammonia volatilization and denitrification are often responsible for the low efficiency of N fertilizers while losses via nitrate leaching and surface run off can be significant in some agricultural systems.

Loss of nutrients represents not only financial loss for farmers, but also degradation of the environment; contributing to eutrophication, acidification and greenhouse gas emission (mainly nitrous oxide, N₂O). Matching fertilizer N supply to plant N demand is an efficient means of reducing N losses, which can be achieved through appropriate timing of application and/or through control release of the nutrients in fertilizers. The use of control (or slow) release fertilizers, or urease and/or nitrification inhibitors to slow down the biochemical processes which may lead to losses, are two means to improving fertilizer use efficiency.

There have been numerous studies on control release fertilizers, and use of urease and nitrification inhibitors, either used alone or in combination in agro-ecosystems. However, the performance of these products relative to urea in crop production field trials has been highly variable. The uncertainty surrounding the relative usefulness of these products is largely due to the lack of adequate understanding of the interaction of these special fertilizers (control release) and inhibitors with soil and environmental variables. A comprehensive study of these control release fertilizers and inhibitors under different crop, soil and climatic conditions will provide future directions for the development of more efficient crop, soil and region specific N-fertilizers and advice under Australian conditions.

Project Aim: Identification of suitable controlled release N fertilizers, and nitrification and urease inhibitors, for improving N-use efficiency and minimising the environmental impact of fertilizer use in key agricultural regions of Australia

Funded by: Incitec-Pivot Limited

Funding period: 2006-2009

Research Team: Associate Professor Deli Chen (Project leader) (UM), Dr Robert Edis (UM), Dr Helen Suter (UM), Dr Arshad Islam (UM)

Contact for further information: Associate Professor Deli Chen,