Information

Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 5FR

Level 1 General Description of Experiment / Monitoring Activities

Purpose

The project objectives were to measure the loss of nutrients and pesticides in surface drainage water from irrigation sugarcane farms and to quantify those input / losses by measuring inflow and outflow waters. This would allow identification of practices that reduce / minimise environmental risk.

Method

Nine farms were chosen at random with monitoring at a tenth farm commencing but later abandoned. A rain gauge was installed at each drainage site to collect data specific to the location being monitored.

Inflow and outflow water samples were collected from each irrigation and rainfall event and analysed for commonly used pesticides and herbicides in sugarcane production (chlorpyrifos, diuro, paraquat, 2,4-D acid, MCPA, glyphosphate, atrazine, ametryn, ioxynil and 2,4-D methyl ester), nutrients (ammonium-n, nitrate-n, and phosphorus) and turbidity.

Key Findings

Atrazine was the most detected herbicide, followed by diuron, ametryn and 2,4-D acid. Chlorpyrifos was recorded on eight separate occasions, while glyphosphate and paraquat remained undetected throughout the two year sampling period. Inflow water rarely recorded the presence of any pesticides.

Nitrogen, phosphorus and potassium in inflow waters did not vary greatly and were lower than outflow waters.

Inflow water from the Burdekin dam contained higher turbidity (used as a measure of sediment loss) than that received in the outflow. However, turbidity increased in outflow waters during intense rainfall events.

The fluctuations in water quality reflected to some degree the farm activities and the time of the year:

  • Fertilising of plants and early ratoons in September;
  • Final fertilising of ratoon crops in late November and December having impacted in early January with reductions following rain late in that month; and
  • Low levels pre-plant in April, but increasing following irrigation of plant cane in July.

The study found that tail-water recycling pits reduced both the frequency and duration of run-off events. Additionally, furrow banking reduced water leaving the site, as did well managed irrigation practices.

Locations

The site was located in the BRIA, approximately 11 km south-east of Shirbourne.

Northing 55 78 25 436

Easting 5 10 958

Related Studies

  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 1C
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 2P
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 3R
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 4CH
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 6F
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 7D
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 8M
  • Nutrients and Pesticides in Surface Drainage Water from Irrigated Sugarcane – Farm 9K

 

Level 2, level 3, level 4 and level 5