This activity is designed to follow on from the activity 'The effects of soil salination', and is aimed at higher-level students. A framework of questions could be provided to assist students in structuring their experiments. The Queensland School Curriculum Council provides other sample planning and reporting sheets in the science Sourcebook materials. Ensure that students label all specimens and that records of germination and growth rates are taken at regular intervals. After familiarisation with the use of electrical conductivity meters, students then design their own experiments to test the amount of salt that can be tolerated by a number of different crop varieties.
Students conduct the experiments they have designed and record data over a number of weeks.
These salt threshold tolerances may then be compared with the values given in Department of Natural Resources Water Fact Sheet W55 for each crop variety tested. Students reflect on the value of this test and the information it provides for future planning. Additional learning Students may perform electrical conductivity tests on soils in the local area and, using their threshold data, determine what crops could be grown in that area.