Question

The two columns below show some parameters and their possible values.

Parameter	Values
P – Gross Command Area	I – 100 hectare/cumecs
Q – Permanent Wilting Point	II – 6 °C
R – Duty of canal water	III – 1000 hectares
S – Delta of wheat	IV – 1000 cm
	V – 40 cm
	VI – 0.12

Which of the following options matches the parameters and the values correctly?

1. P-I, Q-II, R-III, S-IV 
2. P-III, Q-VI, R-I, S-V
3. P-I, Q-V, R-VI, S-II
4. P-III, Q-II, R-V, S-IV

Answer 1

Correct Answer - Option 2 : P-III, Q-VI, R-I, S-V

Concept:

Gross command area (GCA):
It is the total area that can be irrigated by a canal so that an unlimited quantity of water is available. A canal is usually aligned along with the watershed between two drainage valleys.

In other words, GCA is the total area lying between the drainage boundaries that can be irrigated by the canal system. It is measured in hectares.

GCA = CCA + UCA

Where,

CCA = culturable command area

UCA = unculturable command area

Permanent wilting point (PWP):

The water content of the soil at which the plant is no longer able to extract water from the soil for its growth.

At a permanent wilting point, films of water are held very tightly and hence plant roots are not able to extract sufficient water for their growth

\(PWP = \frac{{\rm{\;Water\;of\;moisture\;held\;by\;the\;soil\;when\;plants\;get\;permanently\;wilted}}}{{\rm Unit~weight~of~water}}\)

It has no unit

Duty of canal water (D)

Duty is defined as the area of the land irrigated by a unit discharge of water flowing continuously for the duration of the base period of the crop.

\({\rm{D}} = \frac{{{\rm{Area\;of\;land\;being\;irrigated}}}}{{{\rm{Rate\;of\;water\;supply}}}} = \frac{A}{Q}\)

Duty is measured in hectares/cumec (ha/cumec)

Delta of a crop (Δ):

It is defined as the total thickness of water required for complete maturity of the crop within its base period. It is measured in cm

The sugarcane crop has maximum delta, i.e Δ = 120 cm. Other crops have a delta of less than 120 cm