Fieldtrip-experiment-edited.docx

Experiment 6

Soil DiversityK. Draheim, B. N. Estrella, K. M. L. Garcia, L. Guillermo

Department of Biological Sciences, College of Science, University of Santo Tomas, España Street, Manila 108

Key words:

Diversity

Line Transect Method

Relative Abundance

Relative Density

I. Introduction

Soils are complex mixtures of minerals, water, air, organic matter, and countless

organisms that are the decaying remains of once-living things. The soil is a unique habitat that

supports rich and diverse life. The properties of soil are determined by environmental factors.

Five dominant factors are often considered in the development of the various soils: the climate,

parent materials, relief, organisms, and the time factor. Organisms, mainly microorganisms,

inhabit the soil & depend on it for shelter, food & water. Plants anchor themselves into the soil,

and get their nutrients and water. Terrestrial plants could not survive without soil; therefore,

humans could not exist without soil either. Structure, color, consistence, texture and abundance

Summary

Sampling techniques allow researchers to draw conclusions for the whole population and its biodiversity, abundance and richness. In the exercise, line transect method was applied, giving a good impression of the actual composition of the area occupied. The soil samples in the area were found to be 45.80% sand, 40.40% silt and 13.80% clay in replicate 1. 44.60% sand, 38.40% silt and 16.17% clay in replicate 2 and, 49.69% sand, 38.51% silt and 11.80% clay in replicate 3. With the Soil Texture Triangle, the soil texture was classified as loam.

of roots, rocks and carbonates can characterize soil. These characteristics allow scientists to

interpret how the ecosystem functions and make recommendations for soil use that have minimal

impact on the ecosystem. Soil characterization data can help determine what kinds of organisms

exist in it.

The determination of population distribution, size, abundance, and richness of organisms

in a particular size of land is just one of the major problems in the study of ecology. This

problem can be resolved through sampling to acquire an estimate of the population. Researchers

can make general inferences about the population as a whole by considering the differences

within the population.

This activity uses line transect method, which is one of the three sampling techniques. A

transect is a path along which one counts and records occurrences of the species of study. Line

transects use a tape or string laid along the ground in a straight line between two poles as a guide

to a sampling method used to measure the distribution of organisms. Sampling is rigorously

confined to organisms that are actually touching the line. Line transects are used to illustrate a

particular gradient or linear pattern along which communities of plants and, or animals change.

They provide a good way of being able to clearly visualize the changes taking place along the

line.

II. Objectives

1.) To identify, measure and record the horizons in a soil profile at a soil characterization site

and its particle size distribution.

2.) To be able to gain an accurate assessment of the composition of a measured area by

looking at a few samples from that area

III. Methodology

The group was assigned to the terrestrial ecosystem. The field work was carried out o n

an island in Bolinao, Pangasinan on March 30, 2016. Only one sampling technique was

employed: the transect method. Simultaneously, soil characterization was performed. Soil

samples were obtained and soil texture analysis was later done in the laboratory.

Sampling using the Transect Method

The line-intercept method, one of the various types of transect methods, was utilized in

the experiment. On a 60-meter baseline, a random point was selected, from which a 10-meter

line (transect), perpendicular to it, was drawn. This transect was lined with a rope marked at 1-

meter intervals. All the living organisms (mostly plants) that touched (above and beneath) the

line were noted, documented, and identified.

Soil Characterization and Soil Texture Analysis

A trowel was used to scrape a few centimeters of soil off the profile to expose fresh soil

face. The soil profile was determined whether it was moist, wet, or dry. If it was dry, it was

moistened with the spray mist bottle. The characteristics of the soil was observed and taken note

of from the top of the soil profile down to the bottom. Distinguishing characteristics such as

color, texture, shapes, roots, rocks, small dark nodules, worms, small animals, insects, and worm

channels were noted. In a vertical line, a nail served as a marker at the top and the bottom of each

horizon. The top and bottom depth of each horizon was measured and recorded. Sample soil was

taken into the laboratory and soil texture analysis was done by sieving. First, the soil sample was

weighed. It was then sieved in four different pore sizes and the four soil samples were then

reweighed. The percent composition was computed and a soil texture triangle was used to

classify the soil sample texture class.

IV. Results

The following ecological sampling via transect line was conducted in Bolinao,

Pangasinan last March 30, 2016 during the BIO203L fieldtrip. Soil samples were collected per

site replicate, sieved and weighed to determine soil texture of the site of interest.

Table 1. Transect line sampling (Replicate 1 – first to 5th meter)

Replicate 11 meter 2 meters 220cm-330cm 3 meters 4m 5m

-no organism observed-rocky and sandy soil

-no organism observed-rocky and sandy soil

-unidentified plant species-rocky and sandy soil

-rocky and sandy soil- leaf of Cocos nucifera above

-no organism observed-more rocks (big) in the soil

-rocky and sandy soil-Panicum repens (torpedo grass)

Table 2. Transect line sampling (Replicate 6th – first to 10th meter)

Replicate 16 meters 7 meters 8m 9meters 10 meters

-Panicum repens (torpedo grass)-soil primarily silt

-Panicum repens (torpedo grass)- Cocos nucifera leaf above-unidentified plant species-soil primarily silt

- root of Ficus stipulosa-Panicum repens (torpedo grass)-rocky and sandy soil

- Mimosa pudica- Tetranychidae sp.(no picture)-rocky, silt, clay mixture of soil

-no organism observed-rocky, silt, clay mixture of soil


Replicate 21 meter 2 meters 220cm 3 meters 4 meters 5 meters

- no organism observed- primarily silt texture

-Cocos nucifera leaf above-primarily silt texture

-unidentified plant sample-primarily silt texture

-Cocos nucifera leaf above-primarily silt texture

- leaf of Cocos nucifera above-primarily silt texture


Table 4. Transect line sampling (Replicate 2 – 6th to 10th meter)

Replicate 26 meters 670cm 7 meters 8 meters 9 meters 10 meters


-unidentified plant sample-soil primarily silt texture

-Panicum repens (torpedo grass)-soil primarily silk texture





Replicate 31 meter 2 meters 3 meters 4 meters 5 meters

-no organim observed-rocky, sandy, with clay soil




-Cocos nucifera leaf above-rocky, sandy, with clay soil

Table 6. Transect line sampling (Replicate 3 – 6th to 10th meter)

Replicate 36 meter 7 meters 8 meters 9 meters 10 meters

-Cocos nucifera leaf above-rocky, sandy, with clay soil


-no organism observed-rocky, sandy, with clay soil



Table 7. Relative density values of species per site

TRANSECTSite Species No. of species Rdi

1

Panicum repens 5 35.71%Cocos nucifera 1 7.14%Ficus stipulosa 1 7.14%Mimosa pudica 1 7.14%

Tetranychidae sp. 5 35.71%plant species #1 1 7.14%plant species #2 0 0%plant species #3 0 0%

Total no. of all species 14

2

Panicum repens 4 44.44%Cocos nucifera 3 33.33Ficus stipulosa 0 0%Mimosa pudica 0 0%

Tetranychidae sp. 0 0%plant species #1 0 0%plant species #2 1 11.11%plant species #3 1 11.11%


3

Panicum repens 0 0%Cocos nucifera 1 100%Ficus stipulosa 0 0%Mimosa pudica 0 0%

Tetranychidae sp. 0 0%plant species #1 0 0%plant species #2 0 0%plant species #3 0 0%


Table 8. Shannon-Wiener Index and Simpson Index values

Species n1H' (Shannon-

Wiener)D

(Simpson)Panicum repens 9 -0.981 0.130Cocos nucifera 5 -1.569 0.036Ficus stipulosa 1 -3.178 0Mimosa pudica 1 -3.178 0Tetranychidae

sp. 5 -1.569 0.036

plant species #1 1 -3.178 0plant species #2 1 -3.178 0plant species #3 1 -3.178 0

N 24 -20.01 0.202H' (Shannon-Wiener) =20.01

D (Simpson)= 0.797

Table 9. Jaccard index values

Sample Sets J (Jaccard)Site 1 and Site 2 -0.5

Site 2 and Site 3 -0.125Site 1 and Site 3 -0.125

Table 10. Mass of sieved soil particles from replicate 1Replicate 1 Mass

Gravel 11.3gSand 47.3gSilt 41.9Clay 15.3

TOTAL 115.8g

Weight of container used for soil types: 1.5g

1.5g x 4 = 6 g

115.8 – 6g = 109.8g (Final total weight)

Gravel:

11.3g – 1.5g x 100 = 8.93% 109.8g

Sand:

47.3g – 1.5g = 0.4171 109.8g

Silt:

41.9g – 1.5g = 0.3679 109.8g

Clay:

15.3g – 1.5g = 0.1257 109.8g

0.3679+0.4171+0.1257=0.9107

Sand: (0.4171/0.9107) x 100 = 45.80%Silt: (0.3679/0.9107) x 100 = 40.40%Clay: (0.1257/0.9107) x 100 = 13.80%


Gravel 15.1gSand 46.1gSilt 39.9gClay 18.5g

TOTAL 119.6g

Weight of container used for all soil types: 1.5g

1.5g x 4 = 6 g

119.6g – 6g = 113.6g (Final total weight)

Gravel:

15.1g – 1.5g = .1197 113.6g

Sand:

46.1g – 1.5g = .3926 113.6gSilt:

Soil character: LOAM

39.9g – 1.5g = .3380 113.6g

Clay:

18.5g – 1.5g = .1496 113.6g

0.3926 + 0.3380 + 0.1496 = 0.8802Sand: (0.3926/0.8802) x 100 = 44.60%Silt: (0.3380/0.8802) x 100 = 38.40%Clay: (0.1496/0.8802) x 100 = 16.17%


Gravel 17.4gSand 49.1gSilt 38.4gClay 12.8g

TOTAL 117.7g

Weight of container used for all: 1.5g

1.5g x 4 = 6 g

117.7g – 6g = 111.7g (Final total weight)

Gravel:

17.4g – 1.5g = 0.1423 111.7g

Sand:

49.1g – 1.5g = 0.4261 111.7g


Silt:

48.5g – 1.5g x 100 = 0.3303 111.7g

Clay:

12.8g – 1.5g = 0.1012 111.7g

0.4261 + 0.3303 + 0.1012 = 0.8576Sand: (0.4261/0.8576) x 100 = 49.69%Silt: (0.3303/0.8576) x 100 = 38.51%Clay: (0.1012/0.8576) x 100 = 11.80%


V. Discussion

Sampling using the Transect Method

In the first replicate, the first two meters of the transect line did not come across any

organism and the soil was rocky and sandy. On the following meters, however, there were

organisms that have been observed. Immediately after the second meter, between 2.20 and 3.30

meters, an unidentified plant species sprawls over the ground. It is green and has dominant,

thick, and fleshy leaves. In the third and seventh meter, leaves of Cocos nucifera (coconut tree)

hung above the transect line. In the fourth meter, no organism was observed and the soil

contained more rocks. In the fifth meter, Panicum repens (torpedo grass) spreads over the

surface. At this point, the soil is still rocky and sandy. Until the eighth meter, torpedo grass was

observed along the transect line. At the sixth and seventh meter, the soil was primarily silt. In the

eighth meter, roots of Ficus stipulosa were seen. In the ninth, Mimosa pudica and Tetranychidae

sp. were observed. The soil from the eighth to the tenth meter was once again rocky but clay was

notable in the last two meters.

In the second replicate, the 10-meter transect line touched primarily silt soil. No organism

was observed in the first meter but Cocos nucifera leaf above the second to the sixth meter was

noted. At 2.20 and 6.70 meters, there were unidentified plant samples. Torpedo grass spread over

the seventh to the tenth meter.

In the third replicate, the soil was rocky and sandy, with a little mix of clay. It was also

notable that the ground was greatly cluttered with masses of dead leaves. In almost the entire

length of the transect line, no organism was observed. However, in the fifth and sixth meter,

Cocos nucifera leaf was observed over the transect line.

The results show the vitality of moist in the growth and development of organisms,

primarily in plants, as in the case of the experiment. More organisms were observed when the

type of soil was moist. From this, it can be interpreted that moist soils contain more nutrients

needed for initiating and sustaining life. Water is indeed essential to all of organisms’ existence.

An extremely high Shannon-Wiener index of 20.01 points out high diversity. On the

other hand, the Simpson index which is 0.797 implies low diversity. For the Jaccard’s indices,

three comparisons were made. Site 1 and Site 2, Site 2 and Site 3, and Site 1 and Site 3 obtained

indices of -0.5, -0.125, and -0.123 respectively.

Soil Characterization and Soil Texture Analysis

Soil texture is the relative proportions of sand, silt, or clay in a soil. The soil textural class

is a grouping of soils based upon these relative proportions. Soils with the finest texture are

called clay soils, while soils with the coarsest texture are called sands. However, a soil that has a

relatively even mixture of sand, silt, and clay and exhibits the properties from each separate is

called a loam. There are different types of loam, based upon which soil separate is most

abundantly present. These are shown in the textural triangle.

The mineral particles of a soil are present in a wide range of size. The fine earth fraction

includes all soil particles that are less than 2 mm. Soil particles within this fraction are further

divided into the 3 separate size classes, which includes sand, silt, and clay. The size of sand

particles range between 2.0 and 0.05 mm; silt, 0.05 mm and 0.002 mm; and clay, less than 0.002

mm. Sand particles are generally primary minerals that have not undergone much weathering.

Clay particles are secondary minerals that are the products of the weathering of primary

minerals. As weathering continues, the soil particles break down and become smaller and

smaller.

Soil texture affects many other properties like structure, chemistry, soil porosity and

permeability. Soil Porosity refers to the amount of pore or open space between soil particles.

Permeability is the degree of connectivity of soil pore space. A highly permeable soil is one in

which water runs through it readily. Coarse textured soils tend to have large, well-connected pore

spaces and therefore high permeability.

Sandy soil has large particles with large spaces or pores between them. Therefore, water

drains through sandy soil quickly. Sandy soils do not hold or retain water very well. As a result,

it is not good for growing most plants. It has fewer nutrients for plants than silt or clay. Silt has

smaller particles and slower drainage than sand, which enables it to retain more water and

nutrients for plants. Clay is very powdery when dry and very sticky and slippery when wet. Pore

spaces between clay particles are very small. It has a tremendous ability to hold water because

water and air move very slowly through clay.

To determine the texture of the soil sample, the percentages of the three soil particles

were determined. In this experiment in replicate 1, we obtained 45.80% sand, 40.40% silt and

13.80% clay. In replicate 2 we obtained 44.60% sand, 38.40% silt and 16.17% clay. In replicate

3 we obtained 49.69% sand, 38.51% silt and 11.80% clay. Using the Soil Texture Triangle, all

replicates were determined to be loam. Loam is composed mostly of sand, silt and a smaller

amount of clay. Loam soils generally contain more nutrients, moisture, and humus than sandy

soils, have better drainage and infiltration of water and air than silty soils, and are easier to till

than clay soils. It is the best soil for growing and nurturing plants.

VI. Conclusion

From the results, it can be deduced that soil determines vegetation. Soil holds minerals

needed by plants to grow and flourish. An important component of soil that contributes largely to

the success of an organism (especially a plant) is moist or water. It carries nutrients that will be

beneficial to the life of the organism.

An extremely high Shannon-Wiener index of 20.01 indicates high diversity. On the other

hand, the Simpson index which is 0.797 implies low diversity. For the Jaccard’s indices, three

comparisons were made. Site 1 and Site 2, Site 2 and Site 3, and Site 1 and Site 3 obtained

indices of -0.5, -0.125, and -0.123 respectively.

A sieve series was used to determine the particle size distribution of the soil sample

obtained from the assigned habitat. The soil samples were found to be 45.80% sand, 40.40% silt

and 13.80% clay in replicate 1. 44.60% sand, 38.40% silt and 16.17% clay in replicate 2 and,

49.69% sand, 38.51% silt and 11.80% clay in replicate 3. With the Soil Texture Triangle, the soil

texture was classified as loam.

Reference:

Lavelle, P. & Spain, A. (2001). Soil Ecology. Dordrecht, The Netherlands: Kluwer Academic

Publishers.

Kang, B.T. & Spain, J.M. (1986). Management of low activity clays with special reference to

Alfisols, Ultisols and Oxisols. Proceedings of Symposium on Low Activity Clays (LAC)

Soils. pp. 107-131.

Ukut A., Akpan U. S., & Udoh B. T. (2014).Characterization and classification of soils in steep

sided hills and sharp-crested ridges of Akwa Ibom State, Nigeria. Net Journal of

Agricultural Science 2 (2), pp. 50-5

Phillips, E. A. (1959). Methods of vegetation study. New York, USA: Henry Holt and Co.

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