Second Lab Report: Balsam Ballerina

BALSAM BALLERINA

LECTURER’S NAME: MADAM DIANA DEMIYAH MOHD HAMDAN

TITLES: SOIL PH ANALYSIS

SOIL WATER HOLDING CAPACITY

SOIL MOISTURE ANALYSIS

COURSE: SS11403 ENVIRONMENTAL SOIL SCIENCE

DATE OF SUBMISSION: 27^TH MARCH 2018

SOIL MOISTURE

In soil science, we can see how water plays its vital role in groundwater recharge, agriculture and soil chemistry. Other than space and air, understanding of water content in soil is one of the focus of scientific research which overall increase and decrease of wetness in various region with different humidity condition and climate. Water stored in soil is called soil moisture where the water is held within soil pores. Soil water is so important as it is one of the major component needed for plants growth. When the soil moisture is optimum for plants growth, plants can uptake water, nutrient and mineral easily from soil. This is because most of the nutrients and minerals will dissolve in water solution before they are absorbed by plants. Soil moisture is a key variable in land-atmosphere interactions: the variations of soil moisture in response to atmospheric conditions which include precipitation, radiation and evaporative demand impact surface turbulent and radiative heat fluxes, thereby potentially feeding back on atmospheric conditions (Alexis Berg, et al., 2014). Therefore, it is clearly shown that a slightly change in environment factors such as rain precipitation and temperature can affect the soil moisture directly.

There are a few terms for soil moisture. Moisture that can easily remove from soil is called readily available water. As soil moisture is depleting, a strong force is required to apply great suction to overcome high tension that holds water particles in the soil. Plants use water for growth and cooling through evapotranspiration process. In short, if readily available water is finished, plants use more energy to extract water from soil. Instead of using energy for growth but to cool down itself, crops production will definitely affect which this is known as stress point. To maintain plant growth in good condition, a suitable level of stress is controlled by water irrigation and this is called as refill point. When a plant is unable to cool down itself, water loss exceeds water extraction from soil, cells will be closed down so that it can recover from harsh condition. This is called wilt point. Lastly, if the water availability drops continuously until too much water loss, cells will die and eventually plant cannot rejuvenate from previous condition which this is known as permanent wilt point.

Generally, soil moisture is just a small component of hydrological cycle but it plays a major role in both agriculture and climate prediction. When there is drought occurring in a particular area, there will be a deficit amount of soil moisture which causes crops productivity to decrease as well. That is why continuous soil moisture measurement can improve crop yield forecasting, irrigation planning for flood and drought (Liza Brazil, 2015).

SOIL WATER HOLDING CAPACITY

Among other usage of soil, soil acts as a medium to accumulate water until it is used by plants. Water is stored in the spaces between soil particles and there is force of gravity consistently pull downward and out of the reach of plants. The counterbalancing force acts on water which keeps it from moving downward is surface tension that causes water to stick to the soil particles. The smaller the soil particles, the larger the surface area, the more water they are able to hold through surface tension. Therefore, the ability to trap water depends much on type of soil.

Soil water holding capacity is a term that all farms should know to optimize their crops production. The water holding capacity is actually the amount of water that given soil can hold for crop use Christina Curell,2011). There is a term named field capacity which means the soil water holding capacity has reached its maximum for entire field. The goal or the common challenge for agricultural producers is to maintain and control water near capacity. When there is water deficit, precipitation from rainwater or water irrigation will be needed to replenish soil profile.

There are two major components that determine water holding capacity of soil which are soil texture and organic matter. From the perspective of soil texture, soil particles with small size such as clay and silt have larger surface area compared to sand particles. When water enters soil with large sandy particles, only a small amount of water stays attached while the remainder all drain and leach downward rapidly. This shows that sand has a low water holding capacity. Oppositely, clay soil has small particles with much larger surface area. When water enters it, strong surface tension holds the water particles tightly from draining downward and only a small amount of remainder leaches through the soil. In short, the larger the surface area, the more and easier to hold water in the soil.

Besides that, soil organic matter (SOM) is also one of the factors that help increasing water holding capacity of soil. This is because soil organic matters have natural magnetism to attract water which means if farm increases the overall soil organic matter percentage, the ability of soil to hold and trap water will improve indeed. Most of the SOM are originated from decayed animals and plants, therefore, with the increase of plant and animal material, the SOM and soil water holding capacity will increase proportionally.

SOIL PH

Soil pH is a measure the concentration of hydrogen ions present in the soil solution. pH scale ranges from 1 to 14, with 7 considered to be neutral. pH less than 7 is said to be acidic solution while if it is greater than 7, it is alkaline or basic. Garden soil pH normally do not hit the extreme, but a slight movement up and down the pH values can affect the health and growth of plants. The bulk of the hydrogen ions concentration is absorbed to the clay soil and organic matter particles which it is known as soil’s reserve acidity. The higher the clay and organic matter content of a soil, the higher the amount of hydrogen ions stored in it.

The main reason why soils in northeast are acidic is due to the leaching of basic cations calcium, magnesium, potassium and sodium leaves the exchange sites on clay particles region where hydrogen ions are replacing them. In addition, human activities especially the use of fertilizers, pesticides and industrial activities that emits sulfur and nitrogen oxides flow into soils through rainwater cause soil to be more acidic than normal.

However, although pH is one of the factors that affect growth of plants, some of the plants love this kind of acidic and alkaline soil condition. For example, balsam, tomatoes, strawberries and amelia chrysanthemum prefer to grow in acidic soils while rosemary, parsley, purple coneflower love alkaline soils. From the other perspective, if an area frequently receives high rainfall level, soils have higher chance to be acidic as natural leaching of minerals from soils. On the other hand, area where the climate is dry and warm with low level of rainfall does not drain out mineral easily from soils and this build up alkaline soils indirectly.

Lastly, since soils tend to acidify over time, appropriate fertilizers may need to be applied on soils so that plants fertility can be ensured therefore crops yield production will not be affected much. Lime and gypsum are commonly used to optimize the soil pH condition in agricultural plantation.

SOIL MOISTURE

1. Objectives:

· Understanding the concept and definition of soil moisture.
·                 To bring the knowledge of soil moisture measurement methods into practice.
·         To learn how to correct the soil weight for soil moisture at air dry (AD) conditions to oven dry (OD) soil moisture.
·         To determine a correction factor to account for the air dry moisture content in subsequent samples weighed for analysis.
·         Determining the moisture content of soil sample

2. Apparatus and Materials:

100gm of soil sample, hexagonal weighing dish, analytical balance weighing scale, spatula, portable soil moisture, pots with sowed seeds, oven

METHOD A – AIR-DRYING (AD) TO OVEN-DRYING (OD) SOIL

3(A). Procedures:

1. The mass of the plastic container was recorded using the analytical balance.

2. A portion of soil sample was taken and placed into a lightweight weighing dish.

3. First step was done by gradually adding soil, estimating it is 100gm and pressed gently using a spatula to make it compact.

4. The soil sample was weighed using the analytical balance. Few additions and removal of soil was done to ensure the soil is 100 gram, minus the weight of the dish, on the scale reading.

5. The initial mass weight of soil together with the dish was recorded.

6. The weighed soil sample was placed out of the laboratory, exposed to air and sunlight, let for a week for air-drying and to be observed later on.

7. After a week, the moisture of the soil was observed by sight and touch.

8. The mass of the soil was recorded.

9. The soil was put into the laboratory oven in a temperature of 80 degree Celsius for an hour, to remove the excess moisture that was left after a week of air-drying.

10. The final mass of the soil after heated was recorded.

Diagram 1: Analytical balance

Diagram 2: Disposable weighing dish, weighs 1.4290 gram each

Diagram 3: 100gram soil on weighing dish

METHOD B: USING PORTABLE SOIL MOISTURE TOOL

3(B) Procedures:

1. The plants were made sure not watered in the early morning before the measurements of its soil moisture were taken.

2. The metal of the portable soil moisture tool was inserted into the soil where the seeds are sowed to measure the soil moisture in each pots.

3. The small button sensor for moisture was pressed and moved the needle from its original position.

4. The readings on the tool were recorded.

4 (A). Results:

Date	Mass of soil with weighing dish (gram)
5^th March 2018	143.4484
12^th March 2018 (initial – after air-dried)	137.0158
12^th March 2018 (final – after been oven-dried)	136.3689

Table 1: Mass of soil after oven-dried

4 (B). Results

Diagram 4: Reading for Pot A

Diagram 5: Reading for Pot B

Diagram 6: Reading for Pot C

Diagram 7: Reading for Pot D

Diagram 8: Reading for Pot E

Pot	Portable Soil Moisture Tool Reading
A	1.0 - Dry
B	1.0 - Dry
C	1.0 - Dry
D	1.0 - Dry
E	1.0 - Dry

Table 2 : Reading of Portable Soil Moisture Tool

5. Discussion

When a soil is sampled it is spread out and dried to air dry moisture content. The exception to this is when drying the soil would affect a biological assay or investigation of biological organisms that are so common in soils. When biological organisms are to be assayed the soil is often not dried and is sometimes placed in cold storage.

Even when a soil sample feels dry after air drying, it contains some water. This water is held too tightly to be useful to plants, but in order to quantitatively report on soil characteristics this tightly held water must be accounted for.

In soil moisture determination usually moist soil samples can be directly put into the oven for drying. However, by using air drying method, the initial moisture content, size of the sample and total sample load (number of sample soil dried in a batch) may affect the drying time. Accordingly, air drying the samples before oven drying may yield better results. That is why to check the soil moisture, it is preferred to air dry it first then put it into the oven instead of directly dehydrate it in the oven just for the sake of faster result.

As stated in the results, all of the pots gave same readings which are 1.0 for soil moisture, which indicated that the soil samples in all of the soils were very dry. This is because we were advised to not water the plants before conducting the experiment hence its dryness, plus the weather in the morning which is sunny. All pots show same results because we only use one type of soil for our whole experiments, so it is relevant. Our soil type is silty loam. It is possible that our soil may be too compact that the water from the other day (after daily watering routine) does not even have enough time to permeate completely into the soil, thus being left there in a stagnant condition and evaporated by air. Typically, a soil contains half solid materials and half pore space, filled by air and water. In poorly drained soilsmost of the small voids are filled with water for long periods of time, leaving too little air. By observing our soil colour which is dark brownish to black, it tells that our soil have poor drainage. This may direct or indirectly affect the soil’s moisture.

SOIL WATER HOLDING CAPACITY

1. Objectives:

· To understand the concept of water holding capacity of soil.

· To determine the water-holding capacity of our soil sample.

· To demonstrate the ability of soil or compost to retain moisture against drainage due to gravity

2. Apparatus:

Cutter, electronic balance, plastic containers, cloth

3. Materials:

Filter papers, two identical aluminium cans, air dried extra soils, disposable gloves, tapwater

4. Procedures:

1. Few holes were made the bottom of a can labeled Can A, which were four holes in this procedure, a filter paper that had been into the same size as aluminium can bottom was placed at the bottom of the can. The weight of can (Can A) along with filter paper is recorded.

2. Step 1 was repeated for another can (Can B) with the same amount of holes

3. Soil was transferred into both cans until they reach the same weight as shown in Diagram 19 below.

Diagram 19

4. The soil was pressed gently to make them as compact as possible, until they form uniform layer on top.

Diagram 20: Soil ought to be compacted

5. The cans with soil are weighed and their weights were recorded.

6. Water was poured into two small plastic containers.

7. Both the cans were placed on each of the plastic containers, until they are in contact with water.

8. The bottom of the cans were soaked until the surface of the soil are moist.

9. The cans were removed from water contact. Water drippings were wiped before measuring the weights.

5. Results:

6. Discussions:

Water holding capacity is the total amount of water a soil can hold at field capacity. One of the main functions of soil is to store moisture and supply it to plants between rainfalls or irrigations. Evaporation from the soil surface, transpiration by plants and deep percolation combine to reduce soil moisture status between water applications. If the water content becomes too low, plants become stressed. The plant available moisture storage capacity of a soil provides a buffer which determines a plant’s capacity to withstand dry spells.

The clay soil had the highest water holding capacity and the sand soil had the least; clay>silt>sand. Clay particles are so tiny and have many small pore spaces that make water move slower (the highest water holding capacity). Sandy soils have good drainage but low water and nutrient holding capacities. Thus, our soil sample is silty loam which result in approximately 33% of the soil’s ability to store and hold in water.

Our plants, impatiens balsamina require frequent watering and needs to be kept moist. In this case, a type of soil that can hold water well will be the most suitable for our plant. However, after conducting an experiment on the water holding capacity of our silty loam soil sample, we found that its capacity is not as much as expected. This might be one of the reasons why all 5 of our pots have different growth rates and some pots have difficulty in germinating the balsam seeds, despite having sowed the same type of seeds as well as planted using the same type of soil. As for the latter aspect, it might be that some pots are too compact or have more debris than the others besides receiving slightly less or more amount of water than the pot with the seeds which have germinated and grow well, which is Pot C. However, to improve the growth of the balsam seedlings, it is advised to water them in the morning, so that excess moisture on the plants gets removed by the evening. This is good for preventing certain diseases on the plants.

NAME OF MEMBERS	MATRIC NO
FARLIANA BINTI PADUPAI	BS17110276
KIM MUN KIT	BS17110536
MARYELL IRISHA BINTI HILLARIAN	BS17110372
NURUL FATIEN NADZIRAH BINTI JAITULLAH	BS17110289
RATNA FAIRUZ BINTI NOOR AZAM	BS17280750
TEO YU ROU	BS17110465

Pot	Portable Soil pH Tool Reading
A	4.8 - Acidic
B	4.6 – Acidic
C	4.3 – Acidic
D	4.2 – Acidic
E	4.6 - Acidic

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HS11 Sains Tanah Sekitaran 2018