Inversion tillage, which would have to be to a depth of about 1-1.2 m, is a highly strenuous and costly operation and in most cases should be ruled out.
Normally, it is better to use a chisel plough or ripper, which breaks up the soil to a depth of 80-100 cm without inverting the layers, to be followed by ploughing to 40- 50 cm.
The land should then be harrowed and then either ditched or, in certain cases, prepared with drainage ditches, to allow the draining off of the water.
The deeper tillage should be done a few months before planting to assist the deepening of the roots and the holding of rain water.