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Organisms and Populations — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations5 Marks
Question
Which element is responsible for causing soil salinity? At what concentration does the soil become saline?
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Answer

Minerals are responsible for causing soil salinity. Following are some of the cause for increase in soil salinity:
  • High level of salt in soil.
  • Water table movement because of landscape features.
  • Human activities; like clearing of land and excess use of synthetic fertilizers.
  • Salt runoff from streets can happen in cold climates because salt is applied on road to prevent snow accumulation.
Measurement of soil salinity: Soil salinity is measured in terms of gram per litre of soil solution or electrical conductivity in dS/ m. Soil salinity is usually determined from an extract of saturated paste of soil and then EC is termed as ECe. When 4 < ECe < 8, soil is termed as slightly saline. When 8 < ECe < 16, soil is termed as moderately saline. When ECe > 16, soil is termed as highly saline.

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