Agricultural irrigation involves applying water to crops through artificial means to ensure adequate water for cultivation, especially in areas prone to drought. Irrigation water can come from groundwater, rivers, lakes, or wells. Benefits of irrigation include drought protection, enabling quick-maturing crops, and ensuring seed germination. Several methods can measure soil moisture levels, including weighing wet and dry soil samples, using a tensiometer to relate soil suction to water content, measuring electrical resistance of an embedded porous block, observing plant wilting patterns, foliage color changes, and growth rates, and using a sand-mixed mini plot that wilts earlier indicating need for irrigation.

1. Perform irrigation and
drainage practices
Agricultural irrigation is the application
of water to crops through artificial means.
Irrigation is primarily used in areas with
sporadic rainfall or potential drought
conditions to ensure that crop soil receives
adequate water for cultivation. The water
utilized in agricultural irrigation can come
from various sources, such as groundwater,
rivers, springs, lakes, wells, or surface water.

2. Benefits of irrigation
1. Irrigation is insurance against drought.
2. It enables the growth of quick maturing
crops.
3. It is a guarantee to the quick germination
of seeds.
4. It is a means of securing early maturity
on most crops.
5. It increases the quality, attractive
appearance, and yield of crops.

3. How to measure soil
moisture?
1. A direct method by gravimetric with oven
drying. The method involves the weighing
of the wet sample, removing the water by
oven drying, and reweighing the sample to
determine the amount of water removed.
The percentage of water in the sample on a
dry-weight basis is obtained by dividing the
difference between wet and dry masses by
the mass of the dry sample and multiplying
by 100.

4. 2. Use of tensiometer. Tensiometer
measures soil water content. Water content in
the soil is then obtained from the calibration
curve relating soil suction to water content
values for specific soils.
3. Electrical resistance method. A porous
block connected by suitable electrodes to an
ohmmeter is embedded in the soil.
Equilibrium is attained when water ceases to
flow into or out of the block. The electrical
resistance corresponding to the water content
at equilibrium is recorded in the ohmmeter

5. 4. Temporary wilting. When water stress
occurs in a plant, cells lose turgidity and
plants show symptoms of wilting.
Temporary wilting may occur at mid-day
when water demand reaches its climax,
especially during the hottest months of the
year. Soil moisture may really be adequate
but transpiration may outpace water
absorption. If this is the case, the plant will
recover by evening. However, if plants wilt
in the morning continuously for 3-4 days,
water may indeed be lacking and the crop
must be irrigated immediately.

6. 5. Color of foliage. Not all plant shows temporary
wilting when water is limited. Instead, their leaves
turned yellowish as in beans and in some cases
bluish-green as in eggplants, as the water is reduced
in the soil. Color is also an indicator of plant variety
where there is nitrogen supply so consider this
when analyzing the situation.
6. Rate of growth of the plants. If the rate of
growth of the crop is sluggish, water may not be
enough.
7. “Feel of the soil”. Get samples from a depth
where most of the roots occur and try to feel the

8. 8. Sand-cum-soil-mini plot technique.
It involves digging a one cubic meter pit in
one part of the field. Mix 5% sand to the soil
that has been dug and return it to the pit.
Now the soil has reduced water holding
capacity. The crop including the test plot is
planted as usual. The plants in the test plot
will start to wilt 2-3 days ahead of those in
the field. Irrigation must be done when
wilting is observed in the test plot.