MODULE 1

Question 1

Irrigation – application of water into the soil; in some areas,
irrigation means to supplement rainfall and serves to
increase production

Answer 1

Irrigation –

Question 2

– removal of excess water within or on the soil; it can be

natural or artificial

Answer 2

Drainage

Question 3

Advantages of Irrigation and Drainage:

Answer 3

-increase cropping efficiency
-increase crop productivity and yield
-increase cropping intensity

Question 4

Agriculture consumes ——-of our total water consumption, and the
majority of this consumption is accounted for by irrigation.
Moreover, roughly half of all harvested rice area and ——-of the
total rice output are irrigated rice.

Answer 4

82% , 70%

Question 5

the largest irrigation scheme,
servicing about 44 % of the total irrigated land

Answer 5

National Irrigation System (NIS) -

Question 6

• relative proportion
  of variously sized
  groups of mineral
  particles in a
  particular soil or
  horizon

Answer 6

Soil Texture

Question 7

– represents the soil which is made up of air, water and
solids.

Answer 7

Soil System

Question 8

TOTAL VOLUME

Answer 8

VT = Va + Vw + Vs
Vv = Va + Vw

Question 9

determines the amount of pore spaces within the soil
- amount of water a soil can hold in a saturated condition

Answer 9

c. Porosity (n)

Question 10

• the ratio of the volume of
  voids in a soil to volume of
  solids

Answer 10

Void Ratio (e)

e = Vv / Vs = n / 1-n

Question 11

Degree of Saturation (DOS)

Answer 11

DOS =( Vw-Vv) x 100

Question 12

lateral movement of water in the ground surface

Answer 12

surface runoff -

Question 13

lateral movement of water below water table

Answer 13

seepage -

Question 14

flow of water from the ground surface into the soil

Answer 14

infiltration -

Question 15

further downward movement of water into the soil

Answer 15

percolation -

Question 16

3 types of Moisture Content Measurement

Answer 16

Direct Method
b. Feel and Appearance
c. Bouyoucos Method
d. Tensiometers

Question 17

• uses the electrical properties of the soil to determine its
  moisture content

Answer 17

. Bouyoucos Method

Question 18

Soil water content and matric potential are not uniquely
related and depend on the path of saturation or desaturation
- Difference in mc readings even same tensiometer readings

Answer 18

Hysteresis

Question 19

• amount of water the soil profile will hold when all its pore
  spaces are filled up

Answer 19

Saturation Point

Question 20

• soil is allowed to drain 2-3 days
• amount of water the soil profile will hold against the soil
  moisture tension of 1/3 bar

Answer 20

Field Capacity

Question 21

• amount of water the soil profile will hold against the soil
  moisture tension of 15 bar

Answer 21

Permanent Wilting Point

Question 22

• amount of water the soil profile will hold against the soil
  moisture tension of 10,000 bar

Answer 22

Hygroscopic Point

Question 23

causes the dissimilar particles and/or surfaces to

cling to one another

Answer 23

Adhesive force -

Question 24

similar or identical particles/ surfaces

to cling to one another

Answer 24

Cohesive force -

Question 25

due to the effect of gravity

Answer 25

Gravitational force -

Question 26

caused by salt or ion concentration differences or gradients

Answer 26

Osmotic forces -

Question 27

water on the soil grains that is not capable of significant movement by the action of gravity or capillary forces

Answer 27

Hygroscopic water -

Question 28

*water that exists in the pore spaces of the soil and is retained against the force of gravity in a soil that permits unobstructed drainage

Answer 28

Capillary water -

Question 29

water that will readily move out of the soil if favorable drainage is provided

Answer 29

* Gravitational water -

Question 30

*held too tightly by capillary forces and is generally not accessible to plant roots

Answer 30

Unavailable water -

Question 31

difference between gravitational and unavailable water

Answer 31

* Available water -

Question 32

drains quickly from the root zone under normal drainage conditions

Answer 32

* Gravitational water -

Question 33

drains quickly from the root zone under normal drainage conditions

Answer 33

* Gravitational water -