51
chip is indicated by the horizontal scale across
the bottom of the chart.
4.4.3.2 Procedure
1. The soil sample be collected following the
standard procedure.
2. The dried soil sample be spread uniformly
over a cardboard sheet and the same be held
directly behind the apertures separating the
closest matching colour chips.
3. The particles of the soil be matched with the
colour chips of the Munsell’s soil colour chart.
4. After matching the sample soil colour with the
colour chip(s) of the Munsell’s chart, the
colour name and the Munsell’s Notation be
ascertained from the chart.
5. The field observations be recorded in the following table:
Locality:
Date:
Time:
Sample no. Hue Value Chroma Colour
Expression
Example:
1.
5YR 5
6
Yellowish
red
5 YR 5/6
4.4.4 Soil Moisture Content
Soil moisture is the water present in the space
between the soil particles. Soil moisture influences the physical, chemical and biological characteristics of the soil. Soil moisture is the % of
moisture (on weight basis) in a soil sample at any
given time. It shows general moisture content of
the soil. Soil moisture helps to understand the
water movement and aeration of the soil.
Main materials required: soil digging tools,
polythene bags, beakers, hotplate, weighing
balance.
4.4.4.1 Procedure
1. Soil samples be collected in polythene bags
following the standard procedure.
2. A 100-ml beaker be weighed empty (W 1 ).
3. From the stock soil sample, c 100 g of fresh soil
be poured out into the pre-weighed beaker.
4. The beaker with the soil be now weighed
(W 2 ).
5. The weight of the soil be determined by
subtracting W 2 − W 1 .
6. The beaker with the soil sample be now kept
on a sand bath and then be placed on a hotplate maintained at 105 °C (approx.).
7. The soil sample will be seen to be getting
dried gradually.
8. After the soil sample is dried, the beaker
with the soil be removed from the hotplate
and cooled.
9. The beaker with the soil sample be now
weighed again.
10. After this, the soil sample in the beaker is
heated, cooled and weighed repeatedly till
constant weight is obtained (W 3 ).
4.4.4.2 Calculation
% moisture content be calculated as follows:
Weight of the empty beaker = say Y g
Weight of the empty beaker + fresh soil sample = say X g
Fresh weight of the soil sample = X − Y = say A g
Final weight of the beaker + dry soil (after getting
constant weight) = say Z g
Dry weight of soil sample = Z − Y = say B g
Therefore, weight of the moisture in the soil
= A – B = say M
Moisture
Weight of moisture
Dry weight of soil sample
%
( )
(
=
(
) ´
M
B
100
) )
(
)
é
ë
ê
ê
ù
û
ú
ú
4.4.5 Soil Bulk Density (BD)
The bulk density or volumetric mass of the soil
is the weight of the oven dry soil per unit volume. It includes the weight of the solid soil particles and the pore space in the soil. The dry
mass, conversely, is the mass of the dry soil
which has no pore space. Bulk density is
expressed as grams per cubic centimetre. It is
said to increase with the depth of the soil due to
the compaction occurring from the pressure on
4.4 Physical Characteristics
chip is indicated by the horizontal scale across
the bottom of the chart.
4.4.3.2 Procedure
1. The soil sample be collected following the
standard procedure.
2. The dried soil sample be spread uniformly
over a cardboard sheet and the same be held
directly behind the apertures separating the
closest matching colour chips.
3. The particles of the soil be matched with the
colour chips of the Munsell’s soil colour chart.
4. After matching the sample soil colour with the
colour chip(s) of the Munsell’s chart, the
colour name and the Munsell’s Notation be
ascertained from the chart.
5. The field observations be recorded in the following table:
Locality:
Date:
Time:
Sample no. Hue Value Chroma Colour
Expression
Example:
1.
5YR 5
6
Yellowish
red
5 YR 5/6
4.4.4 Soil Moisture Content
Soil moisture is the water present in the space
between the soil particles. Soil moisture influences the physical, chemical and biological characteristics of the soil. Soil moisture is the % of
moisture (on weight basis) in a soil sample at any
given time. It shows general moisture content of
the soil. Soil moisture helps to understand the
water movement and aeration of the soil.
Main materials required: soil digging tools,
polythene bags, beakers, hotplate, weighing
balance.
4.4.4.1 Procedure
1. Soil samples be collected in polythene bags
following the standard procedure.
2. A 100-ml beaker be weighed empty (W 1 ).
3. From the stock soil sample, c 100 g of fresh soil
be poured out into the pre-weighed beaker.
4. The beaker with the soil be now weighed
(W 2 ).
5. The weight of the soil be determined by
subtracting W 2 − W 1 .
6. The beaker with the soil sample be now kept
on a sand bath and then be placed on a hotplate maintained at 105 °C (approx.).
7. The soil sample will be seen to be getting
dried gradually.
8. After the soil sample is dried, the beaker
with the soil be removed from the hotplate
and cooled.
9. The beaker with the soil sample be now
weighed again.
10. After this, the soil sample in the beaker is
heated, cooled and weighed repeatedly till
constant weight is obtained (W 3 ).
4.4.4.2 Calculation
% moisture content be calculated as follows:
Weight of the empty beaker = say Y g
Weight of the empty beaker + fresh soil sample = say X g
Fresh weight of the soil sample = X − Y = say A g
Final weight of the beaker + dry soil (after getting
constant weight) = say Z g
Dry weight of soil sample = Z − Y = say B g
Therefore, weight of the moisture in the soil
= A – B = say M
Moisture
Weight of moisture
Dry weight of soil sample
%
( )
(
=
(
) ´
M
B
100
) )
(
)
é
ë
ê
ê
ù
û
ú
ú
4.4.5 Soil Bulk Density (BD)
The bulk density or volumetric mass of the soil
is the weight of the oven dry soil per unit volume. It includes the weight of the solid soil particles and the pore space in the soil. The dry
mass, conversely, is the mass of the dry soil
which has no pore space. Bulk density is
expressed as grams per cubic centimetre. It is
said to increase with the depth of the soil due to
the compaction occurring from the pressure on
4.4 Physical Characteristics