9.1  EM-31 surveying

EM-31 surveying is being undertaken on a large scale in CICL’s area of operation.  EM-31 data, combined with soil drilling and crop water use information, is used to identify areas that use excessive amounts of water to grow crops due to insufficient quantities of clay in the soil profile.  This information is used to assist in effective planning of farm designs.

EM-31 survey targets

An EM-31 survey is a prerequisite for obtaining LWMP incentives and is a high priority component of the Coleambally LWMP. The target date for the completion of the EM-31 surveying project is June 2005.  Figure 9.1 and Figure 9.2 show the progress against the targets.  The figures show that EM-31 surveying is likely to be completed on time, but the drilling and interpretation may extend beyond the scheduled completion date.

Plate 9.1  Horizon Australia Soil & Water conducting proof drilling for interpretation of EM-31 maps

Figure 9.1  EM-31 field surveying completed since project commencement

Figure 9.2  EM-31 survey progress since October 1998

The coverage of EM-31 in the CIA and Kerarbury LWMP areas is presented in Figure 9.3.  CICL closely monitors progress to ensure implementation issues are identified and addressed as quickly as possible.

Figure 9.3  EM-31 status in the CIA and KCA

An EM-31 survey consists of four stages.  Each stage must be carried out before an EM-31 survey is certified complete.

1. Field surveying
2. Raw data mapping
3. Soil drilling
4. Interpretation of EM-31 and soil drilling data

Table 9.1 presents the status of EM-31 field surveying, interpretation and information packages in CICL’s regions.  The data shows that the landholders in all regions have embraced EM-31 technology.

Table 9.1  Number and proportion of farms for which field surveys, interpretation and information packages have been commenced/completed

During the year, field surveying was completed over about 16,665 ha and was commenced on another 90 farms. Field surveys have now commenced on 312 farms and have been completed on 195 of those farms. Mapping of a further 58 farms was completed this year, with a total of 144 farms now fully mapped.

To date drilling has commenced on 108 farms, 100 of which are completely drilled.

A total of 3,101 drills have been performed in the CIA.

Interpretation of EM-31 and drilling data is now complete for 69 farms. Of these, 50 farms have had results forwarded to their nominated Whole Farm Plan (WFP) contractor.  Fifty-four farms received information packages.

This year CICL made a strategic decision to outsource EM-31 services for the completion of the EM-31 project. The successful contractor now provides all EM-31 field surveying and raw data mapping services to CICL as well as meeting half of our soil drilling requirements. The services of a second drilling contractor have been retained to meet EM-31 drilling demands.