Here is a term paper on ‘Water-Logging’ for class 6, 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short term papers on ‘Water-Logging’ especially written for school and college students.
Term Paper on Water-Logging
Term Paper Contents:
- Term Paper on the Definition of Water-Logging
- Term Paper on the Causes of Water-Logging
- Term Paper on the Effects of Water-Logging
- Term Paper on the Detection of Water-Logging
- Term Paper on Prevention and Remedies for Water-Logging
Term Paper # 1. Definition of Water-Logging:
Water is the most important requirement of plant life. It acts as a nutrient carrier. The nutrients get dissolved in the water and are carried in solution to the plant structure. This does not mean that any quantity of water is useful in plant growth. In fact, excess water if present in the soil is either a waste or is detrimental to crop growth.
The nutrients are produced in the soil only when the soil is sufficiently ventilated (or more specifically, aerated). In addition to the presence of water, plant roots also require proper air circulation. For good crop growth the condition of the soil in the root zone should be such as to provide free circulation facilities to air and water at the same time.
When the crop root-zone gets deprived of proper aeration due to the presence of excessive moisture or water content the tract is said to be water-logged. To create such conditions it is not always necessary that the underground water-table should enter the crop root-zone. Sometimes the water-table is below the root-zone depth, but the capillary water zone extends in root-zone depth. It makes the air circulation impossible by filling the pores in the soil.
The water-logging may be defined as rendering the soil unproductive and infertile due to the presence of excessive moisture and creation of anaerobic conditions. It represents saturated condition of the soil especially that of the crop root-zone with water. In extreme cases the water even appears at the field surface and turns the land into swamps and marshes.
The phenomenon of water-logging can be best understood with the help of a hydrologic equation, which states that,
Inflow = Outlet + Storage
Here inflow represents that amount of water which enters the sub-soil in various processes. It includes seepage from the canals, infiltration of rain water, percolation from irrigated fields and subsoil flow.
The term outflow represents mainly evaporation from the soil, transpiration from plants, and underground drainage of the tract.
The term storage represents change in the ground-water reservoir.
Term Paper # 2. Causes of Water-Logging:
In the light of hydraulic equation mentioned above, the main factors which are responsible for raising the water-table are mentioned below:
i. Inadequate drainage of over-land runoff increases the rate of percolation and in turn helps in raising the water-table.
ii. Uncontrolled flood water from rivers may infiltrate into the soil.
iii. Seepage of water from the earthen canals also adds significant quantity of water to the underground reservoir continuously.
iv. Sometimes the subsoil does not permit free flow of subsoil water. It accentuates the process of rising up of water-table.
v. Irrigation water if used in excess over the fields raises the water-table in absence of good drainage facility.
Term Paper # 3. Effects of Water-Logging:
The water-logging affects the land in various ways. All the after effects of water-logging, however, make the soil infertile and unproductive.
The various after effects of water-logging are the following:
i. Creation of Anaerobic Condition in the Crop Root-Zone:
When the aeration of soil is satisfactory bacterial activities produce the required nitrates from the nitrogenous compounds present in the soil. It helps the crop growth. When anaerobic condition is created in the soil due to excessive moisture content, the plant root do not get required nourishing food or nutriments. As a result crop growth is affected badly.
ii. Growth of Water Loving Wild Plants:
When the soil is water-logged water loving wild plant life grows abundantly. This wild growth prevents the crop growth.
iii. Impossibility of Tillage Operations:
When the land is water-logged fields cannot be tilled properly. The reason is that the soil contains excessive moisture content and it does not give proper tilth.
iv. Accumulation of Harmful Salts:
Upward movement of water brings harmful salts in the crop root-zone. Heavy concentration of sodium carbonate and chlorides and sulphates of calcium, sodium, magnesium and potassium in ground water as also in irrigation water is harmful to crop growth. Excess accumulation of these salts may turn the soil alkaline. It hampers crop growth.
v. Lowering of Soil Temperature:
Presence of excessive moisture lowers the temperature of the soil. In low temperatures the bacterial activities are retarded. It affects crop growth badly.
vi. Reduction in the Time of Maturity:
Untimely maturity of the crops is the characteristic of water-logged lands. Due to this shortening of crop period crop yield is reduced considerably.
Term Paper # 4. Detection of Water-Logging:
The water-logging is indicated when the ground water reservoir goes on building up continuously. When the storage starts building up, in the initial stages crop growth is actually increased because more water is made available for the crop growth. But after sometime water table rises very high and the land gets water-logged. Finally the land is rendered unproductive and infertile.
The problem of water-logging develops in its full form slowly. Therefore, its early detection is possible by keeping a close watch over the fields and also on the variations in the ground water level.
A comparative reduction in crop yield in spite of irrigation and fertilization and early maturity of crops indicate the symptoms of waterlogging. Also when harmful salts start appearing on the fields as white incrustation or deposits it indicates that water-logging is likely to follow. In worst cases the water table rises so high and close to the ground surface that the fields turn into swamps and marshes.
The best way of keeping a watch over the problem of water-logging is by observing variations in the ground-water level. It can be done by measuring the depth of water levels at regular interval in the wells dug in the area. Continuous high water levels indicate that the ground water storage is building up which may create water-logging in the area.
Term Paper # 5. Prevention and Remedies for Water-Logging:
The problem of water-logging may be attacked on two fronts. First is preventive measures, which keep the land free from water-logging. Secondly remedial measures may be adopted at reclaim the water-logged area. But in principle both the measures aim at reducing the inflow and augmenting the outflow from the ground water reservoir.
Preventive measures include the following:
(a) Controlling Seepage from the Canals:
The seepage loss may be reduced by adopting various measures for example:
(i) By Lowering the F.S.L. of the Canals:
Loss may be due to percolation or absorption but when the F.S.L. is lowered the loss is reduced to sufficient extent. It is of course essential to see that while lowering the F.S.L. command is not sacrificed.
(ii) By Lining the Canal Section:
When the canal section is made fairly watertight by providing lining seepage loss is reduced to quite a good extent.
(iii) By Introducing Intercepting Drains:
They are generally constructed parallel to the canal. They give exceptionally good results for the reach where canal runs in high embankments.
(b) Preventing the Loss of Water due to Percolation from the Field Channels and Fields:
The percolation loss can be reduced by using the water more economically. It may also be done by keeping intensity of irrigation low. Then only small portion of the irrigable tract is flooded and consequently the percolation loss takes place only on the limited area. It keeps the water-table sufficiently low.
(c) Augmentation of Outflow and Prevention of Inflow:
It may be accomplished by introducing artificial surface and underground drainage grids. It may also be achieved by improving the flow condition of the existing natural drainages.
(d) Quick Disposal of Rain Water:
Quick removal of rain water by surface drains is a very effective method of preventing rise in water table.
Remedial measures include the following:
(e) Installation of Lift Irrigation Systems:
When a lift irrigation project, in the form of a tube-well irrigation system is introduced in the water-logged area the water- table gets lowered sufficiently. It is found to be very successful method of reclaiming water-logged land if tube wells are installed in good number.
(f) Implementation of Drainage Schemes:
The water-logged area may be reclaimed by introducing over land and underground drainage schemes.
Summarizing, the most effective and efficient anti water-logging measures are:
(1) Lining of canals.
(2) Provision of surface drains for drainage of water.
(3) Implentation of tube-well projects.
Other methods are of local importance and hence benefit derived from them is limited.