Innovative management techniques to reduce waterlogging

Introduction

Waterlogging should be seen as a major threat to a farmer’s potential income. The losses attributed to waterlogging in Tasmania, especially in high rainfall years, run into the millions of dollars. What management techniques can be used to mitigate these losses and how can they be justified financially?

Before making any management decisions to reduce waterlogging, it is beneficial to have an understanding of where the problem areas lie, the size of the areas, how often losses occur and what are the potential earnings if waterlogging is significantly reduced.

A monitoring program can be implemented to analyse all of the available data. These can include, but are not limited to, the following:

• Soil aspects – type, health status, depth, characteristics, organic matter, electrical conductivity, compaction, topography, available water-holding capacity.
• Water – soil moisture, water table depth, entry point (next door, over irrigation, rainfall), direction of movement (on surface or sub-surface), exit points, irrigation management.
• Plant/crop analysis – visual inspections (by ground or air), vigour mapping (NDVI), health/sap checks, yield mapping.

Once all the data has been collected, informed decisions can be formalised to make management changes to reduce losses.

Innovative management techniques

There are many tools available to reduce crop losses from waterlogging, some have been listed below:

Management systems

• Controlled traffic farming,
• minimum/no tillage, conservation or strip tillage,
• sub-soiling,
• crop selection,
• livestock considerations to reduce compaction, and;
• surveying and planning for drainage  including watershed simulation.

Drainage

• Surface drainage:
  • Shallow field drains,
  • large excavated ditches,
  • land forming,
  • open excavated drains,
  • raised beds, and;
  • hump and hollow.

• Sub-surface drainage:
  • Agpipe/tile installation,
  • mole ploughing, and;
  • gravel mole ploughing.

Irrigation management

• Machinery selection – choosing the right pivot nozzles for your soil type,
• irrigation scheduling,
• control systems,
• variable rate irrigation (VRI), and;
• salinity considerations.

Conclusions

After making changes, it is vitally important to continue monitoring to gauge improvement and to prompt further action. This system of monitor, take action, analyse data and repeat the process helps ensure that there is a reduction in crop losses attributed to waterlogging. It is far easier to select the low hanging fruit first. Consequently it is recommended that you choose the easiest option first and then progress to the harder projects.

Useful resources

For more information please refer to my Nuffield report via the Nuffield International website

Contact details

Greg Gibson
Gibson Ag Pty Ltd
PO Box 17, Hagley, Tasmania 7292
03 6392 2103; 0419 528 165
gibsonag@bigpond.com