Water Requirement of crop is a important part because India is primarily an agricultural country. Most of the Population is dependent on agriculture for their livelihood.
Factors required for full & successful growth of crops.

1. Proper warmth / Temperatures

2. proper moisture

3. Suitable soil

4. Proper method of cultivation

5. The right amount of air.

Types of soil & suitable crops:

The type of soil is important in cultivation because the sail Provides structural support, nutrients & space for storage of water &  the activity of bacteria for the growth of plants.


1) Black Cotton soil – Is rich in magnesium, iron, aluminium &  lime. It is poor in nitrogen & organic matter & phosphorus. Cotton, sugarcane, groundnut, whole, lower, rice, tobacco, etc.

2) Alluvial soil – It is a mix of sandy loam & clay soil it is rich in humus & phosphoric acid but poor
in potash & N₂ Bajra, maize, jute, gram, soybean, clouds, etc.

3) sandy soil- is dry with some quantity of nitrogen. present in it.
Drought-tolerant crops like barley & millet.

Crop Season:

It is the period required for the growth of a particular crop.

In Maharashtra, 5 types of crops season are considered.

Water Requirement of Crop :

The total number of & how a crop requires water from the time it is sown to the time it is harvested is called crop water requirement.

It varies with crops, place & season.

→ factors affecting crop water requirement.

1. Type of soils

2. Typo of crop

3. Rainfall & wind

4. Method of cultivation5. sunshine, temp. humidity

6. Management

Consumptive use of Water /Evapotranspiration:

It is the depth of water consumed by the plant in the process of evaporation & transportation during
crop growth.

water consumed by accompanying weed growth as well as water deposited by dew or rainfall & subsequently evaporated without entering the plant system is also part of evaporation.

A modified method for computation of consumptive use of water:

ET= ∆H +0.27 Ea / ∆ -0.27


ET = evapotranspiration in mm of H₂O/ day
H = daily heat budget al surface in mm
A = slope of the saturated pressure curve
Ea = evaporation n mm of H₂o/ any


1. Duty (D) / Flow duty:

– It is the area in hectares irrigated by 1 cup (m³/sec) of water supplied continuously throughout the coop period for a particular crop.

– Unit is hectares/cumer

– e.g. If 1 cumer of water is supplied continuously to the rice field throughout the crop period
about 850 hectares of rice will be matured… The duty of irrigation for rice crops is 850
hectares/cumec on the field.

2. Delta (∆): expressed in cm

– It is the total depth of water required by a crop to come to maturity.

– Depth of each watering is generally 6cm to 10cm.
For- eg Rico crop requires a 10 cm depth of water after an intervention every 10 days during its
crop period of 120 days.

– no. of waterings = 120/ 10 = 12
⇒ ∆= 12 x 10 cm = 120 cm

3 . Crop Period:

– It is the period in the number of days a crop takes from the instant of its sowing to that of its

4 . Base period (B):

– It is the period no. of days from the first watering at the time of sowing to the last watering before

– It is the panic in which water is provided for irrigation

– it is generally less than the crop period.

5. Command Area :

The area on the downstream side of the project to which water can reach by gravity is called
the command area.

I) Gross Command Aina (GCA).

● Gross Command Area (GCA) is the overall land area that is enclosed by two drainage
boundaries and can be part of an irrigation project. It involves supplying water to
agricultural land through a network of canals. In simpler terms, it refers to the total area
where water can be provided for farming through a system of canals.

● It Conning batten/fertile and, local ponds, villages, roads

II) Culturable Command Aroa (CCA):

● It is the total area that can be brought under cultivation.
CCA= GCA — Unculturable area

III) Irrigation command Area (I.C.A):

● It & the part of C.C.A that can be irrigated AlI the C.C.A cannot be irrigated because of
high promotion.

6. intensity of Irrigation (I.I):

It is the percentage of culturable command areas that can be irrigated during a given season.
e.g. if the C.C.A is 1000 hectares & 600 hectares can be irrigated in the Kharif season, then
I.I = 600/1000 X 100 = 60%.

7. Time factor:

It is the ratio of the no. of days the canal has defacto run to the no. of days of the irrigation period
(i.e. the actual operating period of a canal upon the crop period).
Design capacity =
water requirement of canal x Time factor

8. capacity factor:

It is the ratio of mean supply discharge in a Canal between a period to the grand capacity
discharge Capacity factor = Qmean / Qmax

9. Crop Rotation:

The planting of different crops in sequence to enrich the soil with different nutrients is known as
crop restation.

10. Yield of drainage basin :

The yield of a drainage basin refers to the amount of water that can be collected from an area
where water flows into a river or stream. It represents the total volume of water that is available
at the exit point of the basin within a year. Essentially, it is the combined runoff from the land
surface over one year.

Also read,


2. Water Requirement of Crops: Learn about Crop Water.


What are the factors affecting crop water requirement?

Which type of crop requires more water?

How do you determine the water requirement of crops?

Which crop requires less water?

What is the role of water in the crop?

What is the first important watering of crops called?

Which crop is highly tolerant to drought?

What are the critical stages of crop growth for water requirement?

Which crop required the highest rainfall?

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