The soil of Southern plain is found between North Ganga plain and Southern plateau (Chotanagpur plateau). This is formed by alluvium deposited by Son, Punpun, Phalgu rivers and their tributaries.
The soil of this plain is divided into four types. i. Karail-Kewal Soil ii. Tal Soil iii. Balthar Soil iv. Kagari Soil
i. Tal Soil
➤ This soil is spread from Buxar to Banka district. This is situated in backwater belt of the Ganga. The area remains under water for months during rainy season due to accumulation of rain water and poor drainage.
➤ The Tal soil varies in colour from light grey to dark grey and in texture from medium to heavy soil.
➤ Due to accumulation of water for considerable period of time, kharif or monsoon crops cannot be grown in this soil.
➤ Rabi or spring crops like wheat, khesari, gram, peas, masoor, lentils, etc are harvested in this soil after water dries up and their yield is quite high.
ii. Karail-Kewal Soil
➤ This is heavy clay soil and characterised by wet paddy lands or dhanhar, spread in the South of Tal soil region.
➤ Karail is an alkaline soil and Kewal is clay and heavy clay loamy soil.
➤ This soil is acidic to alkaline in nature with deep brown to yellow and light yellow in colour.
➤ This is highly balanced with high water absorption capacity and high fertility in nature. It is well suited for both rice and rabi crops such as wheat, linseed, bajra, pulses and gram.
iii. Balthar Soil
➤ It is developed between Chota Nagpur plateau and South Ganga plain’s transitional zone.
➤ It is found in Kaimur plateau to Rajmahal hills in narrow belt ranging from 5 to 15 km.
➤ The soil is less fertile and has less water absorption capacity.
➤ It is acidic in nature and is dominated by sand and gravels. This is red and yellow in colour. The soil is red in colour due to the presence of iron contents.
➤ Maize, jowar, bajra, gram are chief crops grown in this soil.
iv. Kagari Soil
➤ This soil is found in the South banks of Ganga river and on the banks of Son, Kiul, Punpun and Phalgu rivers in the form of thick embankments.
➤ It is rich in lime and brown in colour.
➤ It is suitable for maize, barley, chilly and mustard crops.
