EXPLORE THE WORLD OF GEOGRAPHY, HISTORY, AND MAPS AN EDUCATIONAL SITE ABOUT GEOGRAPHY AND HISTORY
Category: SOIL
HERE YOU WILL GET KNOWLEDGE ON SOIL COVERING AREAS SUCH AS
DEFINITION OF SOIL
FACTORS FOR SOIL FORMATION
THE IMPORTANCE OF SOIL
SOIL COMPOSITION AND PROPERTIES
DEFINITION OF SOIL PROFILE
SOIL PROFILE AND ITS CHARACTERISTICS
CLASSIFICATION OF SOIL ACCORDING TO TEXTURAL GROUPS
DEFINITION OF SOIL EROSION
AGENTS OF SOIL EROSION
TYPES AND EFFECTS OF EROSION TO SOCIAL ECONOMIC ACTIVITIES
RELATIONSHIP BETWEEN POPULATION GROWTH AND RATE OF SOIL EROSION ON THE QUALITY OF LIFE
WAYS OF CONTROLLING SOIL EROSION THROUGH THE APPLICATION OF VARIOUS CONSERVATION TECHNIQUES
The nature of climate in an area like Karamoja in northeastern Uganda is dry throughout the year. This gives chance to blowing winds to erode the soil.
When people settle on a steep relief, they clear the vegetation encouraging running water to carry soils down the slope. This is experienced in Kigezi region mainly Kabale and Kisoro.
Overstocking which results into overgrazing like in Karamoja region. This clears the vegetation leaving bare land which is easily carried by either wind or running water.
Rapid population growth rate which results in land fragmentation and continuous clearing of vegetation on steep slopes like as in Kigezi south western Uganda. This accelerates running water erosin.
Use of poor farming methods such as monoculture, communal grazing which leads to overgrazing like in Karamoja and some parts of Ankole Masaka corridor thus accelerating soil erosion.
Heavy rain fall received in an area especially on steep slopes which have been deforestated, this cause running water to carry down soil like in Elgon slopes eastern Uganda.
Volcanic soils when repeatedly cultivated like in Kigezi south western Uganda, they lose their fertility and therefore easily carried down slope by running water.
Ignorance of the local people about the control measures of erosion. Such people continuously deforestate and over cultivate on steep slopes like as in Kasese on foothills of Rwenzori which encourages soil erosion.
Practices of polygamy and land inheritance have led to increased land fragmentation, deforestation and vegetation deletion as in Kigezi south western Uganda thus automatic soil erosion.
Burning bush especially by nomads during dry seasons so as to regenerate paratable pasture for their animals. This in turn leads to erosion.
This is the removal of topsoil by water leading to the formation of small channels called rills.
Sheet erosion
This is the uniform removal of topsoil over a large area especially from the sloping land as a result of the overflow of water. This type of erosion is difficult to notice or detect because of uniformity.
Gulley erosion
This occurs when the rills are deepened by water to form depressions called gulleys
Splash erosion
This occurs from the impact of raindrops hitting the earth’s surface and the soil particles are splashed in different directions leaving behind small depressions.
Wind erosion
This is the removal of topsoil by wind and in most cases, it is the lighter particles that are eroded. This type of erosion is common in dry areas and in areas with little or no vegetation
Soil erosion is wearing away of soil particles due to the action of erosion agents such as moving water, ice, and wind. Erosion, whether it is by water, wind, or tillage.
Soil erosion involves three distinct actions – soil detachment, movement, and deposition.
Topsoil, which is high in organic matter, fertility, and soil life, is relocated elsewhere “on-site” where it builds up over time or is carried “off-site” where it fills in drainage channels.
Soil erosion reduces cropland productivity and contributes to the pollution of adjacent watercourses, wetlands, and lakes.
water erosion is the result of rain detaching and transporting vulnerable soil, either directly by means of rain splash or indirectly by rill or gully erosion
The following are forms of water erosion
Rain drop or splash erosion
Erosion preceded by the destruction of the crumb structure due to the impact of a falling raindrop on the surface of the soil is termed as splash erosion.
Sheet erosion
It is the fairly uniform removal of soil in thin layers from the land surface, often scarcely perceptible, especially when caused by wind.
Areas, where loose, shallow topsoil overlies compact soil, are most susceptible to sheet erosion.
Rill erosion
A form of water erosion in which numerous very small and more or less straight channels are produced; the channels get obliterated by ordinary use. It can be removed by normal tillage operations.
Gully erosion
A form of water erosion in which gullies are produced by the combination of unattended rills.
Stream bank erosion
Stream banks are eroded by water either flowing over the sides of a stream or scouring at the base.
It is aggravated by the removal of vegetation, overgrazing or cultivation near the stream banks.
Soil Degeneration is the Decline in the usefulness of a soil.
Types of soil degeneration
Physical soil degeneration
This is a Decline in the use of soil in which texture, structure, moisture, and quality of soil are affected.
causes of physical soil degeneration
Deforestation which leads to the removal of vegetation which forms a protective cover of the soil exposing it to erosion agents.
Overgrazing which causes excessive loss of water from the soil causing it to become loose and fine-grained and easily eroded.
Poor Cultivation Techniques i) Pulling hoe along the surface when removing weeds which loosen the soil and when it rains its washed away. ii) Ploughing of land downslope which accelerates soil erosion. iii)Cultivation of steep slopes and along river banks which encourages soil erosion. iv) Burning which destroys vegetation covering the soil exposing it to erosion agents. v) Growing crops on the same piece of land from season to season sucks nutrients from the soil making it fine, loose, and easy to be eroded. vi) Planting crops such as maize whose foliage doesn’t provide adequate soil cover encourages soil erosion. vii) Cultivation in areas that suffer prolonged droughts which loosen the soil causing it to be exposed to erosion during dry seasons.
Heavy rain resulting in excessive soil erosion and thus poorly aerated.
Drought deprives the soil of moisture which holds the soil together causing particles to loosen making it to be easily brown by the wind.
Excavation works such as quarrying, open-cast mining, building of estates and road construction which loosen and expose the soil to erosion agents.
Soil erosion which robs the soil of top fertile layer.
Chemical soil degeneration
this is the decline in usefulness because of changes in mineral nutrients of the soil.
Causes of chemical soil degeneration
Leaching which makes minerals inaccessible to shallow rooted crops.
Excessive application of fertilizers which interferes with bacterial activity and causes the soil to become too acidic and unable to support a variety of crops.
Excess water causing water logging causing acidic conditions.
Planting one type of crop repeatedly which makes the soil deficient of some nutrients.
The excessive drought which causes the accumulation of salts in the topsoil.
Burning such as in slash and burning kills micro-organisms causing nitrogen deficiency when nitrogen-fixing bacteria is killed.
Biological soil Degeneration
Degeneration due to decline of organic content of the soil and organic matter.
Causes of biological soil degeneration
Deforestation deprives the soil of its organic content and moisture making it loose and more vulnerable to erosion.
Burning such as in slash and burning which kills micro-organisms causing a low decomposition rate which robs the soil of organic matter.
Overgrazing causes the removal of vegetation causing excessive loss of water from the soil and hence reduced micro-organism activity resulting in a shortage of humus.
Drought and excessive moisture may lead to a shortage of essential organisms such as bacteria, earthworms, termites, and burrowing animals.
Soil conservation is the practice of protecting and preserving the quality and fertility of soil. This can be done through a variety of techniques, such as terracing, crop rotation, contour plowing, and the use of cover crops.
The goal of soil conservation is to prevent erosion, maintain soil productivity, and preserve natural resources for future generations. It also includes practices like agroforestry, conservation tillage, and restoration of degraded land.
It helps to improve the soil health and fertility as well as water holding capacity, which results in better crop yields and reduced risk of crop failure due to drought.
The following are Soil Conservation methods
Crop rotation
This is the planting of different crops on the same piece of land.
it can also be defined as the movement of crops from site to site on the farm in a planned sequence
This helps to control monoculture and its effects.
advantages of crop rotation
it interrupts pest-host cycles and prevent the buldup of pests weed and pathogens.
it allows crops to access nutrients from different soil depths basing on their rooting characteristics
intergrating cover crops and fallow periods into rotation help build soil organic matter and improve aggregation
here, trees are planted in areas where they have been cleared or areas where trees have never been planted. The planted trees help in controlling the effects of heavy raindrops and the speed of the wind, which are major agents of erosion.
Mulching
This is the covering of soil with different materials e.g. grass so that it can be able to store moisture in the soil. The stored moisture then helps to keep the soil intact hence reducing soil erosion.
Controlled grazing e.g. paddocking, zero-grazing, and tethering
This can help to reduce the effects of overgrazing like eating up all the vegetation from the ground.
this will help to hold soil partials together, hence reducing soil erosion.
Strip cropping
This is the planting of grass between strips of crops and the grass helps to trap the moving soil.
Contour plowing
this is where cultivation takes place along contours on a hill. Farmers cultivate around a hill and not up and down the hill to prevent soil run-offs. It’s common in Kigezi among the Bakiga and the Kenyan highlands.
Controlling bush burning
which is a necessary measure, especially among the nomads.
Using the Umatengo system
here, pits are dug on steep slopes to trap eroded soil, and plants are cultivated between the pits. This system is mainly used among the Matengo people of South-Eastern Tanzania.
measures should be enforced so that pressure on land is reduced e.g. resettling people away from highland areas to lowland areas.
BENCHTERRACING
This method is to break up the sloping land into steps. A bench terrace is a broad bank of earth, with gently sloping sides contouring the field.
The system looks like a set of steps.
The purpose of this soil conservation measure is to reduce the speed and amount of run-off water and to ensure proper land use
HILLSIDE DITCHING
This method breaks up a long slope into a series of short slopes so that the water runoff would be interrupted or prevented from running down the slope. Practices employed are:
The crops are planted between the two hill side ditches. A cover-crop or mulch must be used.
The ditch is done along the contour of the slope.
The planting of grass or small trees on the land around a gully.
Check dams can be built across gullies to reduce the speed with which the water flows
Crops can be grown in ridges, which would be along the slope.
Ridges are similar to terracing but are smaller. This would prevent water from running straight down the hill.
Contour ploughing along the slope of the land would prevent the formation of rills and gullies.
Planting different crops in strips which run along the contours helps to control erosion. When one crop is harvested, only a fraction or single band would be exposed at a time. Thus the runoff would be very slow.
The soil structure should be maintained by ensuring that an adequate amount of humus is present.
goals of sustainable soil health management program
to sustain high crop productivity and crop quality in food and fibre production
to minimize environmental quality and human health risk associated with agricultural production
