Regarding the reclamation of saline soils, which of the following statement is/are correct?

•        The salts are to be leached below the root zone and not allowed to come up. However this practice is somewhat difficult in deep and fine textured soils containing more salts in the lower layers. Under these conditions, a provision of some kind of sub-surface drains becomes important. •        Flooding and drainage are to be repeated 5 or 6 times, till the soluble salts are leached from the soil to a safer limit. •        Intermittent flooding is more efficient than continuous ponding. •        Scrape the salt layer on the surface of the soil with spade.