Acute Magnesium deficiency is seen when ratio is

Acute Magnesium deficiency is seen when the ratio is lower than 0.2.
Magnesium deficiency is a condition in which the amount of magnesium in the blood is lower than normal. The medical name of this condition is hypomagnesemia.
Magnesium deficiency in plants is common where the soil is not rich in organic matter or is very light. Heavy rains can cause a deficiency to occur by leaching magnesium out of sandy or acidic soil.