Water Requirement of Crops MCQ with answer and solution

Concept

Causes and factors of land waterlogging

Formula

NONE

Step-by-step solution

1. Waterlogging occurs when the soil root zone becomes saturated, elevating the water table close to the ground surface. 2. Over-irrigation causes excessive percolation, while canal seepage contributes continuous influx to groundwater. 3. Subsurface seepage from adjoining higher ground levels also adds water to lower lands, making all listed options valid factors. Answer: D

Explanation

Waterlogging occurs when the water table rises close to the ground surface, saturating the crop root zone and cutting off air supply. Excessive application of irrigation water, canal seepage, and underground lateral flow from adjacent higher elevations all contribute to raising the ground water table. Therefore, all these factors collectively act as major causes of waterlogging in agricultural lands.

Why the other options are wrong

A) Over-irrigation is a major cause of waterlogging, making it a valid factor included in Option D. B) Seepage from adjoining high lands raises the water table, making it a valid factor included in Option D. C) Canal seepage directly contributes to waterlogging, making it a valid factor included in Option D.

Shortcut

Waterlogging causes include over-irrigation and seepage from canals or highlands.

Common mistake

Selecting a single cause like over-irrigation instead of recognizing that canal and highland seepage are also major causes.