Information

Environmental impacts of irrigated sugarcane production: Nitrogen lost through runoff and leaching

Level 1: General Description

Purpose

This study monitored the loss of nitrogen from runoff of irrigated and rain-fed sugarcane farms in North Queensland.

Method

Water and N balance was measured over three sugarcane crops at three contrasting sites in different parts of the Burdekin region, covering a range of soil types/textures and irrigation management practices.

The experimental data were used to parameterise the APSIM-Sugarcane cropping systems model, and the model then used to ‘infill’ missing data and develop more complete water and N balances for each of the crops at the three sites.

Key Findings

The amount of leaching to occur from the site varied depending on the soil texture. The findings conclude that N loss through leaching and runoff below the root zone are no higher in irrigated sugarcane production than in rain-fed production systems. If high yields are not achieved, the potential N losses to the environment may be high, although the dominant pathway of these losses (runoff, leaching or denitrification) may be site-specific. Improved irrigation management could help reduce N losses but, with the exception of N lost from runoff in coarse textured soil.

Location

The sites were located on commercial sugarcane farms with all crops furrow irrigated.

One site was located at Delta adjacent to the Burdekin River, where groundwater is the dominant irrigation water source.

The Delta site was 2.5 ha in area.

Keywords

Great Barrier Reef; Water quality; Deep Drainage; APSIM; Nitrous oxide; Nitrogen balance

 

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