Question

Continuously water-logged soils are disadvantageous for plant growth

Answer 1

Waterlogging and inundation slow pasture growth in winter and delay the spring flush. Pasture growth in winter is at least five times more valuable than extra production in late spring. Waterlogged legumes grow more slowly than waterlogged grasses, so waterlogged pastures become grassy and weedy.
In wet years, waterlogging reduces the area that can be cropped. When paddocks are waterlogged shortly after seeding, germination and emergence are often reduced; and crops may have to be re-sown when the soil is firm enough to support machinery.
Waterlogged and inundated areas contribute recharge to saline aquifers, are very susceptible to water erosion and are prone to soil structure decline if cultivated or stocked when too wet.