Lab Report 2 : Sengkuang
Second Lab Report : Sengkuang
Lecturer: Mdm. Diana Demiyah Mohd Hamdan
Group Members :
1.0 INTRODUCTION
Water holding capacity designates the ability of a soil to hold water. It is useful information for irrigation scheduling, crop selection, groundwater contamination considerations, estimating runoff and determining when plants will become stressed. Soil moisture available for plant growth makes up approximately 0.01 percent of the world's stored water. Soil texture and structure greatly influence water infiltration, permeability and water-holding capacity. Soil texture refers to the composition of the soil in terms of the proportion of small, medium and large particles (clay, silt, and sand, respectively) in a specific soil mass. For example, a coarse soil is sand or loamy sand, a medium soil is a loam, silt loam, or silt and a fine soil is a sandy clay, silt clay, or clay. Water holding capacity varies by soil texture.
Soil moisture is a key variable in the climate system. It is known having influences on hydrological and agricultural processes, runoff generation, drought development and many other processes. Soil moisture controls evapotranspiration over land and hence plays a crucial role in the water, energy, and carbon cycles. 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. Soil moisture has an all-determining influence on our life on earth. It ensures that trees and crops can grow, that roads and green hillsides are stable and that we are not permanently enveloped in dust storms. A wide range of measures can influence soil hydrology. Therefore, measuring the amount of soil moisture is extremely important for nature management and the maintenance of plants and soil. The chemical composition of the moisture in the pores of the soil is important for agriculture and for the prevention of future groundwater pollution.
1.1 OBJECTIVE
1.1.1 Water Holding Capacity
· To record the water holding capacity of the plant soil.
· To identify the water holding capacity of the soil samples.
1.1.2 Soil Moisture
· To identify the soil moisture status for efficient irrigation.
· To record the soil moisture every pots of the plants.
· To study the suitable condition of plant to grow.
2.1 MATERIALS
2.1.1 Water Holding Capacity
1. Soil sample
2. Filter paper
3. Tin
4. Plastic container
5. Water
6. Electronic balance
2.1.2 Soil Moisture
1. Plant soil
2. Portable soil moisture tool
2.2 Procedure
2.2.1 Soil Water Holding Capacity
1. A filter paper was took and it was placed at the bottom of the tin box.
2. The tin was weighted along with the filter paper.
3. Some soil was took and transferred into the tin box. (Make sure all sample soil was tested had the same amount of volume.) All the soil samples were tested. If only there is one soil sample type, did it two times.
4. The soil was pressed gently as compact as possible until a uniform layer on top.
5. The tin box was weighted and its weight was recorded.
6. Water was poured into a weight plastic container and two small plastic rods was put to support the tin box float in contact with water.
7. The tin box was leaved undisturbed until water surface on top of the soil and soil is moist.
8. The tin box was lifted and dripping water from the tin box bottom was wiped before the weight was measured.
2.2.2 Soil Moisture
1. Before watering the plant, the soil moisture of the plant soil was checked using the portable soil moisture tool.
2. The soil pH was checked using the soil pH meter.
3. The soil moisture that were air dry in the previous lab was checked. If it is not completely dried out, the soil sample was put in the oven and heat up at 80 degrees Celcius for about one hour and checked again.
4. After soil is completely dried out, the dry soil was weight.
3.0 RESULTS
3.1 Soil Water Holding Capacity
Table 3.1 shows the result collected for water holding capacity analysis
Figure 3.1 shows tin box was leaved undisturbed for water holding capacity analysis
Soil water holding capacity is the amount of water that a given soil can hold for plant use. Of the water entering a soil profile, some will be stored within the rooting zone for plant use, some will evaporate and some will drain away from the plant root zone. Soil water holding capacity is controlled primarily by the soil texture and the soil organic matter content. Soil texture is a reflection of the particle size distribution of a soil. An example is the soil that we use, sandy clay loam soil that has 58.33% sand, 16.67% silt and 25% clay sized particles. In general, the higher the percentage of silt and clay sized particles, the higher the water holding capacity. The small particles (clay and silt) have a much larger surface area than the larger sand particles. This large surface area allows the soil to hold a greater quantity of water. The amount of organic material in a soil also influences the water holding capacity. As the level of organic matter increases in a soil, the water holding capacity also increases, due to the affinity of organic matter for water.
A good soil can retain moisture long enough to maintain a plant between rainfalls and throughout dry periods. Based on the experiment, the percentage of water holding capacity for soil sample A and B are 40.90% and 42.53% respectively. There is only a slightly different percentage between these two samples as we just use the same type of soil. It can be conclude that the soil that we use have average percentage of water holding content which is 41.72%.
Table 3.2 shows results collected for soil moisture analysis
Figure 3.2 The soil moisture of the soil in the pots was taken using the portable soil moisture meter.
Soil moisture is the water occupying the pore spaces between soil particles. Surface soil moisture is the water that is in the upper 10 cm of soil, whereas root zone soil moisture is the water that is available to plants, which is generally considered to be in the upper 200 cm of soil (Dr James E. Arnold et al, 1999). Soil moisture links together the water, energy, and carbon exchanges between the land and the atmosphere. Observing soil moisture measurements allows for an assessment of the entire Earth system, and analyzing global changes is extremely important for understanding future climate change impacts. Soil moisture measurements in agricultural settings provide important information for drought early warning. The upper 200 centimetres of soils is classified as the “root zone soil moisture” and is important for describing the water that is available to plants (Liza Brazil. 2015). Soil moisture is a key variable in controlling the exchange of water and heat energy between the land surface and the atmosphere through evaporation and plant transpiration.Soil moisture also helps to understand the water movement and aeration of the soil.
Soil moisture had been used to measure how much water is held between soil particles. Even we just use only one type of soil for planting the Sengkuang, we still analysed the soil moisture of the soil from Bukit Kokol for each pots. There is slightly different reading of soil moisture for each pots. It could be due to the slightly different amount of water that had been watering for the plant every day. The absorption of water by the soil for every pots could be different, thus affect the soil moisture.
1.0 CONCLUSION
In conclusion, water holding capacity is the amount of water in the soil. Soil water holding capacity is restrained mainly by the soil texture and the soil organic matter content. The larger the surface area the easier it is to hold onto water, so it affects its water holding capacity and become higher. The soil that we used has the moderate percentage of water holding capacity which is 41.72%.
A soil able or not able to retain water is determined by the size of the soil's particles and the texture soil. Soil moisture of the soil we use is not really high due to soil particles and texture. The sandy clay loam soil has more sand particles. It retained water but not as much as compared to other type of soils.
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