Second Lab Report : Kacang Tanah

FACULTY OF SCIENCE AND NATURAL RESOURCES

SS11403 SAINS TANAH SEKITARAN

SEMESTER 2 2017/2018

Date of Submission: 27th March 2018

MRS. DIANA DEMIYAH BINTI MOHD HAMDAN

TITLE : Soil pH and Water Holding Capacity of Soil

NAME	MATRICS NO.
AIDA IZZATI BINTI MD. HUSIM	BS17110523
AKHMARUL IMAN BIN RAHMAN	BS17110521
EMMELDAH JOSEPH	BS17110310
HEW JET XIONG	BS17110443
IVY IMELDA MOENTEN	BS17110049
NUR FAIQAH BINTI ZULKIPLI	BS17160701

1.0 Introduction

           Soil moisture is one way of determining when crops need irrigation and how much irrigation water to apply. This could save water, use less energy, reduce pumping cost, increase yields, and help protect the environment from excess irrigation. Soil moisture can be measured or monitored more effectively and accurately using a variety of commercially available soil moisture monitoring systems. Some of these systems provide continous data collection.  The sensors which are used to measures the water content of soil are called Soil moisture sensors. With increasing number of population but limited land resource, the demand for food is constantly increasing. Now, better production of crop is essential to fulfill the demand. Water plays an active role in the development of the crops. Better crops leads to the high yields. It is important to know when to water and how much to water constantly for the better production of corps. Use of correct Soil moisture sensors helps to ease out the pain which can monitors and keep records about the changes in soil moisture starting form cultivation to harvesting period of crops. Proper water management is possible through the use of this sensor technology. Soil moisture is a key variable in the climate system. By controlling evapotranspiration, soil moisture impacts the partitioning of incoming radiation into sensible and latent heat flux. Furthermore, it represents an important water and energy storage component of the regional climate system. (Seneviratne et al., 2006).

             Soil pH is a measure of the acidity and alkalinity in soils. pH levels range from 0 to 14, with 7 being neutral, below 7 acidic and above 7 alkaline. The optimal pH range for most plants is between 5.5 and 7.0; however, many plants have adapted to thrive at pH values outside this range. Because pH levels control many chemical processes that take place in the soil. Soil pH or soil reaction is an indication of the acidity or alkalinity of soil and is measured in pH units. Soil pH is defined as the negative logarithm of the hydrogen ion concentration. The pH scale goes from 0 to 14 with pH 7 as the neutral point. As the amount of hydrogen ions in the soil increases the soil pH decreases thus becoming more acidic. From pH 7 to 0 the soil is increasingly more acidic and from pH 7 to 14 the soil is increasingly more alkaline or basic. The soil pH can also influence plant growth by its effect on activity of beneficial microorganisms. Bacteria that decompose soil organic matter are hindered in strong acid soils. This prevents organic matter from breaking down, resulting in an accumulation of organic matter and the tie up of nutrients, particularly nitrogen, that are held in the organic matter.

                   Soil water holding capacity is a term that all farms should know to optimize crop production. Simply defined soil water holding capacity is the amount of water that a given soil can hold for crop use. Water is held in soil in various ways and not all of it is available to plants. The amount of water available to plants is therefore determined by the capillary porosity and is calculated by the difference in moisture content between field capacity and wilting point. This is the total available water storage of the soil. The portion of the total available moisture store, which can be extracted by plants without becoming stressed, is termed readily available water. Irrigators must have knowledge of the readily available moisture capacity so that water can be applied before plants have to expend excessive energy to extract moisture.

                 The amount of soil water available to plants is governed by the depth of soil that roots can explore (the root zone) and the nature of the soil material. Because the total and available moisture storage capacities are linked to porosity, the particle sizes (texture) and the arrangement of particles (structure) are the critical factors. Organic matter and carbonate levels and stone content also affect moisture storage. Poor structure, low organic matter, low carbonate content and presence of stones all reduce the moisture storage capacity of a given texture class. Clays store large amounts of water, but because they have high wilting points, they need significant rain to be able to supply water to plants. On the other hand, sands have limited water storage capacity, but because most of it is available, plants can make use of light showers regardless of how dry they are before the shower. Plants growing in sand generally have a more dense root system to enable them to access water quickly before the sand dries out.

2.0 Objectives

1) To understand soil moisture.

2) To improve water use efficiency by soil moisture measurement.

3) To determine the soil of soil.

4) Explain how water holding capacity is affected by soil type.

5) Explain what determines a soils moisture water holding capacity.

3.0 Materials

1. Soil moisture

soil pH meter, soil.

2. Soil pH

Spoon, beaker, filter paper, test tube, funnel, pH paper, pH colour chart, soil pH meter, soil and delonized water.

3. Soil water holding capacity

Filter paper, tin box, plastic container, plastic rod, water and soil.

4.0 Procedures

Soil moisture

1. Before watering the plant, the soil moisture of the plant soil was checked using the portable soil moisture tool.

2. Then, the soil pH meter was used to check the soil pH.

3. Check the soil moisture that were air dry previous lab week.

4. If it was not completely dried out, put the soil sample in the oven and heat up at 80 degrees Celsius for about one hour and check again.

5. After soil is completely dried out, the dry soil was weighed.

Soil pH

1. A few spoonful of soil into a jar/beaker was transferred and stir solution mixed with deionized water.

2. The solution was filtered into a folded filter paper place on a funnel sitting on a test tube.

3. The pH paper was used to test the pH of each soil solution.

4. The pH paper was dipped into the soil solution and take it out to dry for a while. *Note the colour and compare with the chart.

5. Photos of the result was taken.

6. The filter solution pH was checked using the soil pH meter in the lab.

7. 3 methods was used to check the soil sample pH.

Soil water holding capacity

1. A filter paper was taken and place it at the bottom of the tin box.

2. The tin was weighed along with the filter paper.

3. Some soil was taken and transferred into the tin box. (Make sure all sample soil tested have the same amount of volume.

4. All soil sample was tested. If only one soil sample type it was done two times.

5. The soil was pressed gently as compact as possible until a uniform layer on top.

6. The tin box was weighed with soil and its weight was noted.

7. A water was poured into a weight plastic container and two small plastic rod was placed to support the tin box float in contact with water.

8. The tin box was left undisturbed until water surface on top of the soil and soil is moist.

9. The tin box was lifted and dripping water was wiped from the tin box bottom before measure the weight.

5.0 Results and observations

Soil sample (Peaty soil)	pH	Moisture
Pot 1	6.0	3.0
Pot 2	5.5	4.0
Pot 3	6.2	3.0
Pot 4	5.7	4.0
Pot 5	5.5	4.0
Average	5.78	3.6

Appendix

 Figure 1 pot 1

Figure 2 pot 2

Figure 3 pot 3

 Figure 4 pot 4

Figure 5 pot 5

Figure 6 Determining the soil pH

These are the result of separated soil pH according to pH paper method and pH meter method:

pH paper: 5

pH meter: 6.07 

Soil water holding capacity

Soil Sample (PEATY SOIL)	Weight of soil (g)	Weight tin + Filter paper (A)	Weight tin + Filter paper + soil sample (B)	Weight tin + Filter paper + wet soil (D)	Weight dry soil B – A = C	Weight wet soil D – A = E	Mass water absorb by soil E – C = N	% of water holding capacity
A	80.6708	9.3362	89.9907	123.1263	80.6545	113.7901	33.1356	29.12 %
B	80.6746	9.6901	90.3616	117.2867	80.6715	107.5966	26.9251	25.02 %

The water holding capacity of the soil is determined by the amount of water held in the soil sample divided by the dry weight of the sample. This can be shown in the following formulae:

Mass water absorb by soil X 100%

          Weight wet soil

From the table above, it can be concluded that soil sample A has the highest water holding capacity among them, whereas, soil sample B has the least capability of retaining water in its soil particles. This is influenced by the amount of each of the soil sample.

6.0 Discussion

Soil pH

The soil pH experiment was done to discover the pH of the soil used which was the peaty soil, taken from the nearby lake in FSSA. After tested the soil with the filter paper and comparing the colour of the soil with the Munsell chart, it was concluded that the pH of the soil was pH4, which was acidic. The soil pH has some indirect effects on plants. The nutrients of the plant can be available or unavailable according to the pH level.

The plant that was planted in the soil was peanut. The most suitable soil pH to grow peanut was with a soil with pH of 5.9 to 6.3. If the pH is below 5.9, lime can be broadcast over the row and it can be work into the top three to four inches of soil. This will help develops the peanuts since it helps increasing the soil pH. However, since we did not use any lime, the peanut grew at a very slow speed. The peanut can barely be seen even after two weeks it had been planted and the soil pH was definitely one of the reason for its slow growth.

Soil water holding capacity

Based on the water holding capacity experiment, the experiment was done twice since there was only one type of soil sample used. However, the amount of soil might not be totally accurate between both of the tin due to some error. The analytic balance machine have no covers at the sides which caused the wind to flow and make it quite difficult to get the accurate weight. The closest weight between both of the tin were recorded. For the first tin used (A), the recorded weight of the soil sample was 80.6708g while the recorded weight for the second tin used (B) was 80.6747g.

For this experiment, the weight of the tin, soil sample, dry soil, wet soil and the mass of the water absorbed by the soil was calculated in order to discover the percentage of water holding capacity. The water holding capacity can be calculated based on the amount of water absorbed by the soil and the weight of the dry soil. The water holding capacity can be affected due the amount of organic matter in the soil sample.

The steps were taken respectively one after another to get the correct percentage of the water holding capacity. After the soil sample was weighted, the tin and filter paper was weighted and recorded. Soil sample was added into the tin and it was weighted again. The soil was wet by placing the tin into the beaker containing distilled water undisturbed until the soil at the bottom of the tin becomes wet. The tin was weighted again. The recorded weight of both the first and second tin with the wet soil were 123.1263g and 117.2867g respectively.

By minusing the amount of the tin with the filter paper and the soil sample, the weight of the dry soil was successfully obtained. Same goes for the wet soil, the weight was successfully obtained and recorded after the weight of the empty tin consisted filter paper was subtracted from the total weight of the wet soil which was wet with the tin and the filter paper. After recorded all the weighed needed, the calculation for the percentage of the water holding capacity can be proceeded. By using the formula (mass water dissolve by soil X 100)/(the weight of the wet soil), the percentage of water holding capacity for tin A was 29.12% while for tin B was 25.02%.

7.0 Conclusion

         Through this experiment, we are finally aware about the importance of the soil pH before growing any plant. We are also enlighten that the soil pH can be increased by adding the lime and the pH need to be maintained throughout the planting process. A very low pH level can render the plant nutrient manganese while at a very high pH level, the plant molybdenum will becomes available in toxic amount. Soil pH also can influences the soil-dwelling organism which in turn can affects the soil conditions and plant health. To conclude, one of the most important factor that need to be taken care seriously before growing any plant is soil pH. If the soil pH used is not suitable with the plant that was planted, the growing speed will be affected of the plant might not grow at all. That is why the soil pH and the plant that is going to be planted need to match or at least, suit each other so that the plant will grow successfully without any problem.

             Through soil water holding capacity experiment, it is proven that a soil with limited water holding capacity such as sandy loam, will reaches the saturation soil much sooner compared to the soil with the higher water holding capacity such as clay loam. Since the type of soil that we used is clay, the percentage of the water holding capacity is quite high. The experiment was done twice since there is only one type of soil used and the average percentage of the water holding capacity between the two results is 37.23%, which is quite high. The water holding capacity is high due to the soil texture and the soil organic matter content. This clay soil that we used is mainly consist of clay which is small particle. The small particles have large surface particles that enable the soil to hold a greater amount of water. Besides, the amount of organic material in the soil also influences the water holding capacity. Due to the affinity of the organic matter for water, if the level of the organic material in a soil increases, the water holding capacity also increases.

8.0 References

1. M.E. Holzman, R. Rivas, M. Bayala (2014) Subsurface soil moisture estimation by VI–LST methodIEEE Geosci. Remote Sens. Lett., 11 (2014), pp. 1951-1955

2. Plaster, E. J. 1996. Soil Science and Management. 3rd ed. Albany: Delmar Publishers

3. Seneviratne, S.I., D. Luthi, M. Litschi, C. Sch ¨ ar (2006): Land-atmosphere coupling and ¨ climate change in Europe. Nature, 443:203-206.

Seenarious. Lawes, R.A 2009 Integrating effects of climate and plant available soil water holding capacity. Volume 113,Issue 3, Pages 297–305