Estimate the leaching requirement when electrical conductivity (EC) value of a saturated extract of soil is 10 m mho/cm at 25% reduction in the yield of the crop. The EC of irrigation water is 1.5 m mho/cm.

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Estimate the leaching requirement when electrical conductivity (EC) value of a saturated extract of soil is 10 m mho/cm at 25% reduction in the yield of the crop. The EC of irrigation water is 1.5 m mho/cm.

(a) 15%

(b) 6.66%

(c) 7.5%

(d) 10%

This question was addressed to me by my school principal while I was bunking the class.

My question comes from Reclamation of Saline and Alkaline Lands topic in portion Water Logged Reclamation and Saline Soils for Agricultural Purposes of Irrigation Engineering

by (106k points)
Right answer is (c) 7.5%

Easiest explanation: The given values are:

E.C value of saturated soil = 10 milli-mhos/cm and E.C value of irrigation water = 1.2 milli-mhos/cm.

The EC of leaching water is assumed to be twice the EC value of saturation soil extract i.e. = 2 x 10 = 20 milli-mhos/cm

L.R = EC of irrigation water / EC of leaching water = 1.5 / 20 x 100%

L.R = 7.5%.

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