Question

Soil salinity is measured by
A) Porometer
B) Potometer
C) Conductivity meter
D) Calorimeter

Answer 1

Hint: Salinity of soil can be caused by waterlogging or improper drainage system or inefficient irrigation. Saline water is a good conductor of electricity, and this property is used for the measurement of soil salinity. 

Complete step by step answer:
Soil salinity is measured by a conductivity meter. As saltwater is a good conductor of electricity, the soil will show higher conductivity. The conductivity is caused by the salts majorly those of sodium, potassium, calcium, and magnesium.

So, the correct answer is option (C): ‘Conductivity meter’.

Additional information: Soil salinity occurs for many reasons, such as:
- Soil formation as a result of weathering of rocks that contain an excess amount of sodium, calcium, potassium, magnesium, etc. These form salt in the soil and mix with it during the rainy season.
- Closeness to marine water Bodies. The soil around saline water bodies such as sea and lakes tends to have high salt content in the soil.
- Agriculture irrigation where the water contains salts or if the water is hard, can create soil salinity.
- The absence of proper natural drainage of water. Geographical areas without a slope or having basin- shaped topography promotes accumulation of salts onto the land itself causing soil salinity.

Note:
- Plants can adapt to grow in saline land. This property is absent in many crops, creating insufficient food production in coastal areas.
- Due to human causes, agricultural areas can turn to saline lands and affect agriculture. This is tackled by making crops resistant to soil salinity.
Plants like mangrove have the natural ability to survive in saline land. So by genetic engineering, the gene which codes for this property is inserted into the host plant to develop resistance to soil salinity.