Final report SRDC Project CG013 Growers working together to improve water quality in the Herbert Sugar Industry

Abstract

The sugarcane area of the Herbert River district is located adjacent to the Great Barrier Reef (GBR). The quality of water entering the GBR lagoon from the Herbert district is one of the most important environmental issues facing the Herbert sugar industry. However, little data on water quality are available from catchments consisting entirely of sugarcane. This project was conducted to establish a number of water quality monitoring sites in relatively small catchments where the land use is solely sugarcane and where individual growers or groups of growers could measure the quality of water in farm drains using simple tools and relate it to their farming practices. Eleven growers volunteered to participate in the programme. They were keen to participate because they felt that sugarcane growers’ reputation of being good custodians of the land had been tarnished by various external studies of water quality and they were eager to demonstrate that their activities were not polluting drainage water. A series of suitable sites for taking and testing water samples were established and V notch weirs were inserted in the drains for the purpose of measuring rates of water flow. A series of simple tools were developed for measuring sediment and nutrients drainage water leaving the farms. An experienced water engineer who had worked in the district for many years agreed to coordinate the project and proceeded to train the growers involved. He also set up and equipped a water analysis laboratory so that the measurements taken by the growers could be validated. Occasional samples were also sent to a NATA accredited laboratory for further validation of the nutrient determinations but also for measurements of pesticide residues. The growers involved in the project have recorded water quality measurements for three years and have also maintained records of on-farm practices that may impact on water quality such as tillage, fertilising, land levelling and herbicide applications and other activities that may impact on water quality. The growers were provided with information on desirable water quality levels. If their measurements exceeded these levels, growers reacted quickly to seek possible explanations for the elevated readings. The project was evaluated at the commencement, mid-term and just before its conclusion. The growers involved developed a list of the critical factors that needed to be achieved in order for the project to be successful. The mid-term evaluation was conducted with members of the Project Consultative Group and the final evaluation was again conducted with the growers involved in the project. Feedback was generally positive but there were a few areas where things could have been improved. The project outcomes consisted largely of improved knowledge, particularly amongst the growers, of what simple techniques are available for measuring nutrients, pH, dissolved oxygen and turbidity of farm drainage water. Growers learnt what constituted high, medium and low levels for the different water quality parameters and developed a better understanding of the relationship between rainfall and discharge characteristics of drains on their farms. They improved their understanding 4 of the relationship between on-farm management practices and water quality and of the accuracy and reliability of the different tools used to measure water quality. An important outcome has been the continued engagement and support of growers involved with the project, and the engagement and support of regulatory and other government support agencies through the project consultative group. This is important for the next phase of the project which aims to expand from 11 growers to around 100 growers conducting water quality monitoring. The existence of a committed nucleus of growers will be essential for helping to inspire others to participate. Likely economic benefits of the project will be increased farm profitability arising from improved farm practices associated with better management of farm inputs such as fertilisers and herbicides. Reduced input costs arising from reductions in soil tillage and more targeted applications of nutrients and herbicides will also contribute. Environmental benefits will arise from improved water quality on farm and in the downstream ecosystem, and improved soil health arising from changes in farming practices. Social benefits will include the empowerment of growers, who are now armed with better information about their farm practices and the likely impacts on water quality; greater confidence amongst growers when interacting with government and environmental groups; and improved attitudes and engagement by growers in sustainable land management.