The correct answer is: a) Acidic
Alluvial soils are formed by the deposition of sediments from rivers and streams. These sediments are typically rich in minerals, but they can also contain high levels of acidity. The acidity of alluvial soils can vary depending on the source of the sediments and the climate in which they are formed.
In Bihar, the alluvial soils are generally acidic. This is due to the fact that the state is located in a tropical climate, which is characterized by high rainfall and high temperatures. The high rainfall and temperatures cause the soil to leach out its minerals, leaving behind a residue of acidic compounds.
The acidity of the alluvial soils in Bihar can have a negative impact on the growth of crops. Acidic soils can make it difficult for plants to absorb nutrients, and they can also make the soil more susceptible to erosion. However, there are a number of ways to manage acidic soils, such as adding lime or gypsum to the soil.
Here is a brief explanation of each option:
- Acidic soils have a pH of less than 7. They are typically found in areas with high rainfall and low evaporation rates. Acidic soils can make it difficult for plants to absorb nutrients, and they can also make the soil more susceptible to erosion.
- Alkaline soils have a pH of greater than 7. They are typically found in areas with low rainfall and high evaporation rates. Alkaline soils can make it difficult for plants to absorb certain nutrients, such as iron and manganese.
- Neutral soils have a pH of 7. They are the most common type of soil. Neutral soils are generally considered to be the most ideal for plant growth.
- Highly saline soils have a high concentration of salt. They are typically found in areas with arid climates. Highly saline soils can make it difficult for plants to grow, and they can also be harmful to human health.