Summary

Studies in the 1980s found that less than 50% of applied N fertiliser is taken up by drill-sown rice crops in the Murray Irrigation Area, and crops relied heavily on native soil N. In the last decade, DPW has been promoted for water savings and crops reportedly have lower N fertiliser requirements. However, whether these lower N fertiliser requirements are a result of greater efficiency of uptake of applied fertiliser, or reflect greater mining of native soil N reserves is not known. This project will use a 15N-labelled fertiliser source (urea) to quantify the recovery of fertiliser N in full flooded vs DPW systems to determine whether DPW systems are more efficient at recovering fertiliser N or whether they lead to greater uptake of native soil N. This study will have strong implications for sustainable N fertiliser use in the rice industry.

Program

Rice

Research Organisation

Southern Cross University

Objective Summary

The objectives of the project are to:
i) Determine the recovery of nitrogen (N) fertiliser (N use efficiency) and yield of rice grown under delayed permanent water (DPW)compared to a control full flood system using 15N isotope

ii) Determine the reliance of DPW vs full flood systems on native soil N