i think 1 metre height is the problem as movement of water across such distance will be tedious and dehydration of the top soil is very possible frequently also depending on soil types

If you need a controlof soil loss it id better touse some wood cutting of a suitable tree. This would propagate easily in wet season and would give a source of fuel like in many agrofestry trials.

On the ridge moisture loss reduces the germination and soil shall not be compact to genetae required temperature for germination for the tuber

Ridges are mostly to avoid extra moisture and surely with ridges there will be less moisture than flat beds. So, moisture difference can be one factor.

Ridge normally keeps less moisture more especially if the soil is can not keep moisture for a long time. so firstly there is a need to know the type of soil you are dealing with before dry planting . Planting on flatbed keeps moisture more especially if the residues are left  on the surface

Big ridges are useful in areas with so much water to reduce the moisture in the root zone of the crop. Ridges tends to dries up faster. Insufficient moisture can cause poor germination because of insufficient temperature or if the soil is sandy the temperature can be too high. If the temperature is high it may also enhance higher osmotic pressure to your seed.