The correct answer is: Improper irrigation practices.
Soil salinity is a problem in some areas of Manipur due to improper irrigation practices. When water evaporates from the soil, it leaves behind salts. If the soil is not properly drained, these salts can build up and make the soil too salty for plants to grow.
Seawater intrusion is another cause of soil salinity, but it is not a major problem in Manipur. Poor drainage can also cause soil salinity, but it is usually not as severe as when it is caused by improper irrigation practices. Excessive fertilization can also contribute to soil salinity, but it is usually not a major problem unless it is done over a long period of time.
Here is a more detailed explanation of each option:
- Improper irrigation practices: When water evaporates from the soil, it leaves behind salts. If the soil is not properly drained, these salts can build up and make the soil too salty for plants to grow. Improper irrigation practices can include overwatering, using too much fertilizer, or not using enough drainage.
- Seawater intrusion: Seawater intrusion is the movement of salt water into freshwater areas. This can happen when the sea level rises, when there is a lot of rainfall, or when there is a lot of groundwater pumping. Seawater intrusion can cause soil salinity, as well as other problems such as flooding and erosion.
- Poor drainage: Poor drainage can cause soil salinity, as well as other problems such as waterlogging and plant diseases. Poor drainage can be caused by a number of factors, including compacted soil, a lack of slope, and the presence of impermeable layers in the soil.
- Excessive fertilization: Excessive fertilization can cause soil salinity, as well as other problems such as nutrient runoff and water pollution. Excessive fertilization can occur when too much fertilizer is applied, or when the fertilizer is not applied properly.
I hope this information is helpful. Please let me know if you have any other questions.