Third Week Lab Report
Third Week Lab Report : Sengkuang to Balsam (Soil Permeability & Soil Salinity Test)
April 10, 2018
Lecturer: Mdm. Diana Demiyah Mohd Hamdan
Group Members :
Name
|
Matrix Number
|
Angie Fan Yan Kai
|
BS17110476
|
Elavarasi A/P Kasirajan
|
BS17160663
|
Ng Jit Mun
|
BS17160693
|
Nielson Edward
|
BS17110462
|
Nurul Huda binti Ibrahim
|
BS17110437
|
Umi Najua binti Roslaily
|
BS17110319
|
Soil Permeability Test
1.0 Introduction
Soil permeability is the ability of the soil to transmit water and air from top to the ground of floor. The permeability is influenced by the size, shape and continuity of pore spaces inside the soil which in turn are dependent on the soil bulk density, structure and texture. Generally, soils are made up of horizon by horizon, and through all of its horizons extending into parent material, a vertical section is formed and called soil profile. Inside the soil profile, the soil quality often varies greatly from one layer to another layer.
Soil permeability is usually tested before any further use of land such as agriculture and construction. For example, before the pond construction, it is important to determine the relative position of permeable and impermeable layer of the soils. The design of the pond should avoid having a permeable layer at the bottom to prevent excessive water loss into the subsoil and the water able to store inside the pond.
Then, many factors affect the soil permeability. Sometimes they are extremely localized by cracks and rocks. Regard to the rate of infiltration and the rate of percolation, the size of the soil pores and the number of pores closely packed have became the vital factor in soil permeability and even in soil texture and soil structure.
Infiltration is the downwards flow of water from the surface through the soil while the rate of infiltration is a measure of its ability to absorb an amount of rain water in a given time. In most cases, the soil permeability is classified from very slow, slow, moderate, rapid and very rapid. Usually the finer the soil texture, the slower the permeability. The arrangement from slow to rapid of the permeability is clayey soils, loamy soils and sandy soil which clayey soils have the finest texture and the sandy soils are coarse texture. Which means the coarse-textured soils have high infiltration rate and fine textured soils has lower infiltration rate and it is influenced by the stability of the soil aggregates. The losses of water and plant nutrient might be greater on course-textured soils. Therefore, some plants are only suitable for some specific soil only.
2.0 Objectives
1. To measure the permeability of soils.
2. To study the relationship between the permeability of soils and the plant growth.
3.0 Apparatus and Materials
(a) Graduated cylinders
(b) Funnels
(c) Test tubes
(d) Test tube rack
(e) Filter paper
(f) Soil samples
(g) Timer
(h) Watercolour paint
4.0 Procedures
1. The test tubes were stood on the test tube rack and funnel on the top of test tube was prepared.
2. The filter paper was folded and inserted into the funnel as soil separate. This was to prevent soil from dropping into the test tube together with the water.
3. The two same amount of soil samples were prepared for each setup as replication for average. The soil was compacted gently.
4. The same amount of water (100ml) was prepared and gently poured in each funnel at the same time.
5. The water was slowly poured to both soil samples at the same time.
6. If the funnel was full of water, the balance water was waited and added after the water was not overflowing in the funnel to finish 100ml of water.
7. After an hour, the water volume in the test tube was measured.
5.0 Results
Soil sample
|
Volume remaining in measuring cylinder (ml)
|
1
|
83
|
2
|
85
|
Average reading
|
84
|
6.0 Discussion
Through this experiment, in the count of one hour, there is an average of 84ml left in the measuring cylinder. Therefore, we obtained the average reading of the permeability of the soil samples is 84ml/h. The percolation rate or hydraulic conductivity of our soil samples is to determine the rate of water absorption of the soil. In the experiment, the absorbed water is 16 ml by deducting the total volume of 100 ml with the remaining water. The percolation rate of our soil samples is 16ml/h. By referring the first lab result, our soils are analyzed as sandy clay loam soil. The texture of this kind of soil is moderately fine therefore the permeability also count as flow in a moderate slow rate. In a result of moderate slow rate, it also represents that in our daily watering, there are only small amount of water losses to the ground while the remaining are absorbed by the plant roots as nutrient source. Besides from the result of the water flow, it also shows our soil samples is less porous and less permeable because of the slow-flowing rate. The soil samples are shrinking to the bottom after stirring and mixing with water. By using the result of this experiment, in these past three weeks, the soils in pot are more compacted and less porosity among the soils compare with the beginning of the experiment. In agricultural terms, permeability helps in determining the amount of water soaked in by soil. The plant growth is affected if the soil is not permeable and allows water to stay on its surface.
Conclusion
In a nutshell, the permeability of our soil samples per unit hour is 84ml/h. This had shown our soil are suitable for agriculture and is good to germinate different types of seeds. Water is the essential for plant growth. Without enough water, the normal plant functions will be disturbed. Therefore, use a moderate permeable soil is a vital factor to grow our plants.
References
Soil Permeability. Retrieved from http://www.fao.org/fishery/static/FAO_Training/FAO_Training/General/x6706e/x6706e09.htm
Soil Mechanics: Flow of Water in Soils. Retrieved from https://www.brighthubengineering.com/geotechnical-engineering/119946-geotechnical-topics-soil-permeability/
Thomas F. Scherer, David Franzen, Larry Cihacek. 1996. Soil, Water and Plant Characteristics Important to Irrigation. NRCS Publications. Retrieved from https://www.ag.ndsu.edu/publications/crops/soil-water-and-plant-characteristics-important-to-irrigation#section-5
Appendix
Figure 1: The filtration of the soil
Figure 2: Soil permeability of sandy clay loam (83ml/h)
Soil Salinity Test
1.0 Introduction
Soil salinity is a term used to describe the salt content within soil. It is a measure of the concentration of soluble salts in the soil. Salt is a naturally occurring mineral within soil and water that affects the growth and vitality of plants (Viti-Notes, July 2017). Soil salinity can be influenced through several different factors ranging from human influence to environmental causes. If the salt content becomes high, the soil becomes known as sodic soil and can present many difficulties when used as a growing medium. In this experiment, water-soluble salts are extracted from soil samples and salt content are measured by electrical conductivity.
The conductivity method is a rapid and accurate method to measure soil salt content. The present tendency is to use the electrical conductivity to represent the total salt content in the soil directly. As the concentration of soluble salts increases, the electrical conductivity of the soil extract increases. Electrical conductivity is expressed in dS/m, µS/cm, or mmho/cm.
2.0 Objectives
This experiment is carried out to identify the electrical conductivity value and also the total salt content of the sandy clay loam soil used to plant balsam. The main aim is to investigate the suitability of sandy clay loam soil toward balsam plant.
3.0 Materials and Apparatus
Air dried soil samples, distilled water, 2mm mesh size sieve, 200ml glass beaker, spatula, vacuum pump, laboratory flask, test tube, test tube rack, conical flask, graduated cylinder, size 42 Whatman filter paper, glass rod, filter funnel, bottle container, electric conductivity meter and electronic balance.
4.0 Procedures
1. Air dried soil samples that have less than 2mm size is prepared.
2. Foreign materials is removed from the soil.
2. Foreign materials is removed from the soil.
3. 100g of soil is make into a saturated paste using distilled water.
4. A combination of 25g of soil and water(distilled water) with different soil : water ratio 1:1 is prepared (Figure 1).
5. After adding water, the 3 mixtures are being swirled for 20 minutes.
6. To carry out vacuum filtration, a size 42 Whatman filter paper was first placed on the funnel before putting the saturated paste.
7. Water is extracted using the vacuum pump (Figure 2).
8. The filtrates are kept in a bottle container and labelled (Figure 3).
9. Electric conductivity of each filtrates were measured using probe (to ensure a more accurate result, the reading for each filtrate were taken twice).
10. Steps 4-9 is repeated twice using mixture of soil and water with soil : water ratio 1:2 and 1:5.
11. Electric conductivity value of soil is recorded.
Figure 1: Soil and water with different soil : water ratio 1:1, 1:2 and 1:5.
Figure 2 :Water were extracted using the vacuum pump.
Figure 3: The filtrate collected were kept in a bottle and labelled.
5.0 Results
Table 1 : Electric Conductivity for Sandy Clay Loam Soil with Different Soil : Water Ratio.
Soil and Water mixture with soil : water ratio 1:1
| |||||
Temperature (⁰C)
|
Electric Conductivity (µS/cm)
| ||||
1
|
2
|
Average
|
1
|
2
|
Average
|
23.2
|
24.0
|
23.6
|
527
|
511
|
519.0
|
Soil and Water mixture with soil : water ratio 1:2
| |||||
Temperature (⁰C)
|
Electric Conductivity (µS/cm)
| ||||
1
|
2
|
Average
|
1
|
2
|
Average
|
23.2
|
23.5
|
23.4
|
1396
|
1433
|
1414.5
|
Soil and Water mixture with soil : water ratio 1:5
| |||||
Temperature (⁰C)
|
Electric Conductivity (µS/cm)
| ||||
1
|
2
|
Average
|
1
|
2
|
Average
|
22.2
|
22.4
|
22.3
|
688
|
677
|
682.5
|
6.0 Discussion
Table 1 shows the electric conductivity (ES) for sandy clay loam soil with different soil : water ratio of 1:1, 1:2 and 1:5. From the results, it can be seen that the electric conductivity values for sandy clay loam soil showed an extreme increase when soil : water ratio is 1:2, with an average of 1414.5 µS/cm but the value decreased to an average of 682.5 µS/cm when soil : water ratio is 1:5. However, to be precise, the electric conductivity value should have shown a gradual decrease in reading from soil : water ratio 1:1 to soil : water ratio 1:5, not fluctuate from one to the other. This is because soil : water ratio of 1:1 are more saturated and are able to trap more ions compare to soil : water ratio of 1:2 and 1:5. Hence, it will contribute to a higher electrical conductivity value than the other two. The reason why an error in reading occured is probably due to the measuring time for each sample are not taken relatively constant after the electrodes are inserted into the solution (International Atomic Energy Agency, 2016).
Although the electric conductivity value of sandy clay loam soil were not being identified accurately, but we can still boldly conclude that sandy clay loam soil are low salinity soil. This is because, Balsam plants have low drought tolerance and hence they have low salinity tolerance (Agdex 518-17, November 2001). Furthermore, the Balsam plants has shown a relatively progressive growth throughout the week in sandy clay loam soil. This indicates that the salinity of sandy clay loam soil is suitable for the growth of Balsam plant.
Conclusion
Every plants vary in how well they tolerate salt-affected soils. Some plants will tolerate high levels of salinity while others can tolerate little or no salinity. Excess soil salinity causes poor and spotty stands of crops, uneven and stunted growth and poor yields. This is because as soil salinity levels increase, the stress on germinating seedlings also increases and will prevent plants from taking up the proper balance of nutrients they require for healthy growth. Therefore, suitable soil with suitable salinity level plays a vital role in the growth of healthy plants.
References
Agdex 518-17, (November 2001), Salt Tolerance of Plants.
International Atomic Energy Agency, (2016), Protocol for Measuring Soil Salinity.
Viti-Notes, (July 2017), Measuring Soil Salinity.
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