Assessment of Pesticide Impacts on the Biological Health of the Rice Ecosystem- Link (April 2007)

Kumar, A Saison, C Grocke, S Doan, H Waller, T Ko,R

2007

This RIRDC report presents results on the Assessment of pesticide impacts on the biological health of the rice ecosystem. The aim of the project was to provide a better understanding of the impact of pesticides on the soil microbiological health in rice systems and on the aquatic ecosystems receiving drainage water from rice bays during the spray-season. Three main objective included the establishment the effects of rice pesticides on soil microbiological health and on the aquatic ecosystems associated with the rice production system. The second was to assess the recovery of ecosystem during the post spraying period and thirdly to contribute towards better management of pesticides used in rice production. The method was split into two areas, investigating the impact on aquatic organism which was undertaken by monitoring study, laboratory bioassays, excotoxicological tests in experimental bays and laboratory experiments. Part two was impacts of pesticides on soil micro- organisms. Field experiments were undertaken in the Murrumbidgee Irrigation Area (MIA) and laboratory experiments, to underpin the field observations. Experimental rice bays were established under field conditions near Griffith, following a statistical design. The conclusion of the project was that some toxicity on organisms due to pesticide residues was observed during the spraying season and recovery was noted with time. While laboratory test showed some potential toxicity of pesticides to soil biological processes, no measurable effect of soil biological health could be established under field conditions.