1. Soil formation is a very lengthy process requiring many years. In the middle Ganga Plain it is formed by the deposition of new alluvium year after year. So it remains immature.
2. Moreover, because of very low gradient (slope) of the plain, it has a poor drainage. This results in the accumulation (gathering) of sodium salts that renders the soil infertile.
3. Thus, soil is infertile and immature in the Middle Ganga Plain.
