Vertosols, are a heavy clay soil that cover a large part of the world, and are used extensively for irrigated agriculture. They are considered to be quite fertile soils, but development is limited by their physical properties. The dominate clay minerals are smectites which give the soil its distinctive shrink-swell properties. Due to their shrink-swell nature, it has been hypothesised that the cracks serve as preferential flow paths for water and soluble nutrients. Increasing environmental awareness of the impact of nutrient runoff from farms and the rising prices of fertilisers has resulted in farmers wishing to increase the efficiency of their fertiliser use, to do this we need a greater understanding of the movement of nutrients in the soil profile. Over the last 100 years various types of lysimeters have been developed to measure the soil solution. However there are still significant areas of unknown in their impact of on soil hydrology, how effective they are in sampling the soil solution and their effect on the sample collected.

This review aims to summarise and analyse the present understanding of the hydrology and chemical properties of Vertosol soils, assessing the need for monitoring the soil solution under irrigated crops grown on these soils. The methods used for soil solution monitoring are also evaluated and suggestions are made for future research.

Our previous research (Cotton CRC project 2.3.04) showed that cotton growers

considered they lacked the capability to monitor the quality of their farm water.

untilst nutrient monitoring kits were being trialled by growers and environmental

officers, pesticide monitoring was too complex and expensive to be considered for

adoption in a BMP program or environmental management system (EMS). Also,

without the capability for assessment of on-farm water quality for reporting the validation of BMP and CRC milestones 2.3.2 could notbe achieved.

However, there is a continuing need for the use of environmentally hazardous herbicides by industry and an increase in regulatory review and environmental pressure with respectto pestidde use.

A clear hypothesis developed: Could rapid and cost effective analytical tools be developed that could be used in the myBMP program and other environmental managementsystems(EMS).

The research team has a history of successful NRM related projects, particularly in the field of environmental dieintstry, analysis and risk assessment to support resource quality research and development of agro-ecosystems. The team also had considerable experience in the development of ELISA technology; Enzyme-Linked Immunosorbent Assay, which relies on the immune response of mammals to detect chemical targets.

This project aimed to build on existing capability and develop rapid portable test kits for pesticides based on ELISA technology (sensitive and cost effective diagnostic tools that). It was envisaged that these simple test kits could be designed for use in BMP systems to monitor target pesticides and ensure on-farm water quality. They would need to cost significantly less than commercial analyses and provide information immediately, thereby enabling cost-effective environmental management. Potential benefits for users include piece-of-mind regarding water quality with respect to conforming to regulation, subsequent uses of water (eg aquaculture), or to verify environmental stewardship (BMP) and improve brand strength. Such tools and their application were also expected to provide the framework to develop sustainability indicators.