First Lab Report: JAGUNG PANDAN (Analysis of Soil Colour and Soil Texture)

Title: Soil Colour and Soil Texture Analysis
Lecturer: Dr. Diana Demiyah Mohd Hamdan
Date of Submission: 24th March 2018

NAME	MATRIC NUMBER
SOW XIAO HUI	BS17110464
KONG WAN LING	BS17110429
AARON CHIN VUI CHANG	BS17160670
NURUL NATASYAH BINTI KANAPIA@HANAFIAH	BS17110546
NURFATIN SOFEA BINTI MOHD HELMI	BS17110574

Soil Colour Analysis

1.0 Introduction

The colour of the soil is usually the first thing people notice. Mostly this is just the topsoil but it does not reflect the entire soil. The topsoil is usually darker than lower layers (or horizons) because this is where organic matter accumulates. Soil colour is usually due to 3 main pigments: black—from organic matter, red—from iron and aluminium oxides and white—from silicates and salt. Colour can be a useful indicator of some of the general properties of a soil, as well as some of the chemical processes that are occurring beneath the surface.

Soil colour does not affect the behaviour and use of soil; however, it can indicate the composition of the soil and give clues to the conditions that the soil is subjected to (Brady, 2006). The development and distribution of colour in soil results from chemical and biological weathering, especially redox reactions. As the primary minerals in soil parent material weather, the elements combine into new and colourful compounds. Soil conditions produce uniform or gradual colour changes, while reducing environments result in disrupted colour flow with complex, mottled patterns and points of colour concentration.

Soil colour is an important soil property that is reported in all soil profile descriptions because it constitutes a useful first approximation of soil conditions and properties. Colour can be estimated with a spectrophotometer or other mechanical device; but it is frequently done by visual inspection. The practice of describing soil colour first began in Russia, where attempts were made to form a cohesive system of soil colour identification. In America, soil colours were occasionally mentioned in reports of the early 1900’s, but no formal system was agreed upon until the 1940’s, when the work of Dorothy Nickerson and Albert H. Munsell led to the use of the colour chip system now employed. The system has led to a uniform and systematic description of soil colour employed in all current scientific literature. Soil colour is used for both soil classification and evaluation. From colour, inferences regarding such things as reduction status (i.e., whether or not a soil remains waterlogged for long periods of time), organic matter content, and mineralogy are possible. For example, red, yellow, or reddish brown colours suggest the presence of oxidized iron and are indicative of good aeration and adequate drainage. Poor aeration and imperfect drainage are indicated by blue and grey soil colours, denoting reduced iron. Similarly, a dark brown soil colour is usually attributed to organic matter. Minerals can be distinguished by inspection from the differing values of redness; acid sulphate soils are frequently in the grey-green-black spectrum; and types of clays present have also been characterized by colour (Bigham, 1993).

1.1 Objective

1) To observe and identify the colour of soil by using Munsell Colour Chart

2.0 Apparatus and Materials

Munsell Colour Book, 5 different soil samples

3.0 Procedure

1) Five soil samples are taken.

2) A pinch of soil is placed in the white spot plate and the colour is determined using the Munsell colour book.

3) The sample is moistened and the colour of the moistened sample is determined.

4) Each soil is repeated and the result is recorded.

4.0 Result and Discussion

Observation:

TYPES OF SOIL	Value	Chroma	Hue	MUNSELL SEDIMENT COLOUR CODE	MUNSELL SEDIMENT DESCRIPTION
Lake of Residential College E	3	3	5 YR	5 YR 3/3	Dark reddish brown
Mountain	6	8	2.5 Y	2.5Y 6/8	Olive yellow
Mangrove	2.5	1	2.5 Y	2.5 Y 2.5/1	Black
Sandy	7	6	10 YR	10 YR 7/6	Yellow
FSSA	6	8	10 YR	10 YR 6/8	Brownish yellow

In general, soil colour is determined by organic matter content, drainage conditions and the degree of oxidation. Red, brown and yellow colour of soils are encouraged by well aerated conditions whereas grey and blue colour soils are encouraged by poorly aerated conditions. Colour alone is not an indicator of soil quality, but colour does provide clues about certain conditions. For example, light or pale colours in grainy topsoil are frequently associated with low organic matter content, high sand content and excessive leaching. Dark soil colours may result from poor drainage or high organic matter content. Shades of red indicate a clay soil is well-aerated, while shades of grey indicate inadequate drainage. In poorly drained soils, the subsoil is greyer in colour.

Soil colour is influenced primarily by soil mineralogy. In well aerated soils, oxidised or ferric (Fe³⁺) iron compounds are responsible for the brown, yellow and red colours you see in the soil. When iron is reduced to the ferrous (Fe²⁺) form, it becomes mobile and can be removed from certain areas of the soil. When the iron is removed, a grey colour remains or the reduced iron colour persists in shades of green or blue. Upon aeration, reduced iron can be reoxidised and redeposited, sometimes in the same horizon, resulting in a variegated or mottled colour pattern. These soil colour patterns resulting from saturation, called “redoximorphic features”, can indicate the duration of the anaerobic state, ranging from brown with a few mottles, to complete grey or “gleization” of the soil. Soils that are dominantly grey with brown or yellow mottles immediately below the surface horizon are usually hydric.

To classify soil colour, a moist representative soil sample is compared to the colour chips in a Munsell colour book. The Munsell colour system describes colour in three parts: hue, value, and chroma. For example, a complete colour description reads 10YR 4/3. Such a notation translates to: a hue of 10YR, a value of 4, and a chroma of 3. Hue is the spectral or rainbow colour and is described by such notations as 10YR (yellow red), 7.5YR (more red, less yellow), 2.5Y (yellow), etc. Each page in the Munsell colour book is a different hue. Value is defined as the relative blackness or whiteness, the amount of reflected light, of the colour. The value designation is found on the left side of the colour book, and increases from the bottom (0 = pure black), to the top (10 = pure white). The chroma notation is the purity of the colour or the amount of a particular hue added to grey. The chroma designation is located at the bottom of each page of the colour book and increases from left (greyest) to right (least grey or brightest).

Table 1: Soil Types and Characteristics and Typical Management Implications According Different Soil Colour

Soil colour	Soil types and characteristics	Typical management implications
Black	These soils are often associated with high levels of organic matter (peats).	-waterlogging or drainage problems -low pH -high denitrification
Black	Vertosols (cracking clay soils)	-workability and tillage problems
White/pale/bleached	These soils are often referred to as bleached or 'washed out'. The iron and manganese particles have been leached out due to high amounts of rainfall or drainage.	-leaching of nutrients -low plant available water
Red	This colour indicates good drainage. Iron found within the soil is oxidised more readily due to the higher oxygen content. This causes the soil to develop a 'rusty' colour. The colour can be darker due to organic matter.	-high phosphorus fixation -low plant available water
Yellow to yellow-brown	These soils often have poorer drainage than red soils. The iron compounds in these soils are in a hydrated form and therefore do not produce the 'rusty' colour.	-moderate phosphorus fixation -low plant available water -compaction
Brown	Soils associated with moderate organic matter level and iron oxides.	-low to moderate phosphorus fixation -low to moderate plant available water
Gleyed/grey/green	These soils are associated with very poor drainage or waterlogging. The lack of air in these soils provides conditions for iron and manganese to form compounds that give these soils their colour.	-waterlogging or drainage problems -high denitrification risk -methane emission hazard

Source: Adapted from Soil Constraints and Management Package

According to the results, the colour for Lake of Residential College E soil is 5 YR 3/3 (dark reddish brown). The accumulation of organic matter in soil gave the soil dark in colour. The soil is well aerated which means that air moves freely into and out of the pore spaces of the soil. Well-aerated soils provide a healthy environment for plant roots. For mountain soil, the colour is 2.5 Y 6/8 (olive yellow). These soils often have poorer drainage than red soils. The iron compounds in these soils are in a hydrated form and therefore do not produce the 'rusty' colour. The soil has moderate phosphorus fixation and it is compact. The colour of sandy soil is 10 YR 7/6 (yellow) while the soil took from FSSA is 10 YR 6/8 (brownish yellow). The colour soil for mangrove soil is 2.5 Y 2.5/1 which correspond to the black colour. The black colour shows high level of organic matter in soil but it is poor drainage at the same time. Although it contains a high level of organic matter, but the poor drainage is unsuitable for plant roots to grow.

5.0 Conclusion

The five different types of soil colour is determined by using the Munsell colour chart. The colour for Lake of Residential College E soil is dark reddish brown (5 YR 3/3) while the mangrove soil colour is black (2.5 Y 2.5/1). For the colour of mountain soil and sandy soil is olive yellow (2.5 Y 6/8) and yellow (10 YR 7/6) respectively whilst the soil in FSSA is brownish yellow in colour (10 YR 6/8). Different soil colour can determine different condition and its properties.

Reference

Bigham,J.M. and E.J. Ciolkosz. 1993. Soil Colour. Soil Science Society of America Special Publication # 31. Soil Science Society of America, Inc. Madison, WI.

Brady, Nyle C. & Ray R. Weil. 2006. Elements of the Nature and Properties of Soils, page 95. Prentice Hall.

Cleland, T.M. 1921. A Practical Description of the Munsell Colour system, with Suggestions for Its Use.

Jackson, R.S. 2014. Wine Science, Fourth Edition: Principles and Applications (Food Science and Technology)

Missouri Career Education. (n.d.). Soil Colour. Retrieved from http://www.missouricareereducation.org/doc/soilsci/SRLesson3.pdf

Odeh, I.O.A. and McBratney, A.B. 2005. Encyclopedia of Soils in the Environment.

Appendix

Figure 1: Munsell Colour Chart Book

Figure 2: Five Different Types of Soil

Soil Texture Analysis

1.0 Introduction

Soils is the most very important for existence of many forms of life that evolved on the earth as it influencing the productivity of our planet’s various ecosystems. Soils is a medium for growth and supply these organisms with the most of their nutritional requirements. Furthermore, soils have its characteristics which are physical, chemical and biological. Soil texture is one of factor for physical properties which play a role for plant growth.

Soil texture is one the most fundamental soil property, one that most influences other soil traits. Soil texture is the proportion of three sizes of soil particles which are sand (large), silt (medium), and clay (small). The texture of a sample can be assigned to one of several texture classes depending on the proportions of sand silt and clay in the sample.

Clay is the most crucial type of mineral particle found in a soil. The small size, clay particles have a very large surface area relative to their volume. This large surface is reactive and has the ability to attract and hold positively charged nutrients ions and these nutrients are very useful to plant roots for nutrition.

2.0 Objective

To compare five different soil types. The experiment will measure and compare the soil texture by using the method of soil texture estimation and the soil triangle.

3.0 Apparatus and Materials
Stop Watch, Jars, Soils (Lake of Residential College E, Sandy, Mangrove, Faculty of Science and Natural Resources and Mountain), Water

4.0 Procedure

(i) Method of Soil Estimation

(a) 2 tablespoons of soil is taken in one hand and water is added drop by drop while the soil was worked until it reaches a sticky consistency.

(b) The wetted soil is squeezed between thumb and forefinger to form a ribbon.

(d) The experiment is repeated to form a ball shape and the texture is determined the shape of the ball for each soils

(ii) The Soil Triangle

(a) The soils is filled into a jar about 60%-70% volume of the jar.

(b) Water is filled into the whole jar and the jar lid is closed tightly.

(d) The sand and large particles are falling to the bottom first.

(e) The jar is leave undisturbed for 24 hours.

(f) The separate layers is marked for each soils.

(g) From the 3 marks on the jar and it can determine by using Soil Textural Triangle.

5.0 Result

(i) Method of Soil Estimation

Location of Soils

Method of Soil Texture Estimation

Soil Texture

Ball Shape

Ribbon Shape

Length of Ribbon Shape (cm)

Lake of Residential College E

19.50

Silt Clay Loam

Sandy

0.00

Sand

Mangrove

15.5

Silt

Faculty of Science and Natural Resources

7.40

Silt

Mountain

22.0

Silt

(ii) The Soil Triangle

Location of Soils

Measurement of Separate Layers (cm)

Soil Texture by using soil triangle

Sand

Silt

Clay

Lake of Residential College E

0.40

4.70

2.00

Silty Clay Loam

Sand

4.50

0.00

Sandy

Mangrove

0.10

5.90

0.00

Silt

Faculty of Science and Natural Resources

0.20

6.30

0.00

Silt

Mountain

0.00

7.50

0.00

Silt

6.0 Discussion

This experiment’s aim was to test different soil samples from different location. This experiment can determine the soil texture of each soils by using ball and ribbon method. Each soil is taken handful and wet so it stick together without sticking to the hand. A ball of about 3cm diameter is made and put down. If the ball fall apart, it is sand. Then, the ball for each soil is rolled into a sausage shape and the length of ribbon shape is measured.

If it does not remain in this form it is loamy sand. If it remains in this shape. Continue to roll until it reaches 15-16 cm long. After that, if it does not remain in this form, it is sandy loam. If it remains in this shape, the sausage shape is bend into a half circle and if it doesn’t, it is a loam.

Based on the result, all soils can form a ball shape and ribbon shape except for sandy and mangrove soils unable to form ribbon shape. All soils have its length of ribbon shape and we can determine the soil texture by its length. In the end, lake of Residential College E is silty clay loam, sandy soil is sand while mangrove, Faculty of Science and Natural Resources and mountain soil are silt.

By using the soil triangle method, the soil texture for the soils have the same result as the method of estimation.

7.0 Conclusion

The soil texture for lake of Residential College E soils is silty clay loam soil, sandy soil is sand soil whereas mangrove, FSSA and mountain soil are silt soil.

References

Edward J. Plaster, 2009. Soil Science and Management. 5^th Edition. International Edition.

Katharine Brown, Andrew Wherrett (2018) Measuring Soil Texture in the Laboratory. http://soilquality.org.au/factsheets/soil-texture-measuring-in-the-lab. Accessed 2018.

Appendix