Lecture 4 Flashcards
Soil classifications are made based on……
properties and behavior of soil
Soil classification is like a language between engineers. True?
Yes
The two types of scientific classification systems are ……
those based on processes of soil development and those based on quantifiable characteristics of the soils.
Soil classification has elements of both of its types. These are sometimes referred to as ……
comprehensive systems
Classification of earth materials for engineering purposes used ………….. which is based on a combination of physical and behavioral properties.
Unified Soil Classification Systems (USCS)
An ingenious feature of ………..the differentiation of silts an clays by means of ……….
USCS, plasticity chart
American association of state highway and transportation officials is used as a guide for classification of soils and ………
soil aggregate mixtures for highway construction purposes.
AASHTO does not classify soul by type but divides them into ……….major groups essentially classifying soils according to their suitability as sub grades.
seven
Federal Aviation Administration (FAA) classification of soils for ………
airport construction
Textural soil classification system defined ……….. major soil texture classifications.
12
The food and agriculture organization of united nation (FAO) developed ………..classification which offers useful generalizations about ……….in relation to the interactions between mail soil forming factors.
supra-national, pedogenesis
Interim Ghana Soil Classification systems was developed in the …….
late 1950’s
United States Department of Agriculture Soil Taxonomy first published in ……. provides an elaborate classification of soil types in several levels namely……
1975, order, suborder, great group, subgroup, family
The USCS was first developed by …….for the purpose of airfield construction during the……..
Professor A Casagrande (1948), WWII
USCS was modified later by Professor Casagrande, the US Bureau of Reclamation and the US Army Corps of Engineers to……
enable the system to be applicable to dams, foundations and other construction
Four major divisions of USCS
- Coarse grained
- Fine grained
- Organic soils
- Peat
Tests required for the classification of soil are…..
- liquid and plastic limit tests
- Particle size analysis test
Broad classification includes two types namely……
Fine grained and coarse grained soil
Soil is classified into …….groups
15
Each soil classification group is designated a symbol consisting of two capital letters. The first letter is based on ……….. and the second is based on ……… and ……….
Main soil type and gradation and plasticity
Major soils of the world are……… based on USDA Soil Taxonomy
12
…………. are young soils that do not show any profile development other than the A horizon.
Entisols
Entisols are found on …….. slopes
steep, rocky
Entisols occur in ……. and ……. regions.
desert and tundra
Some ……. are found on fresh deposits from rivers, glaciers and sand dunes.
Entisols
May be difficult for plants to obtain nutrients from entisols true or false?
true
Entisols of …….. are good for crop cultivation.
Large river valleys and associated shore deposits.
……….are more developed than entisols but still lack most of the features of older soils.
Inceptisols
Inceptisols contain enough moisture to support plant for at least ……..
Three months of the year
Inceptisols are found on ………….
fairly steep slopes and resistant parent materials
Some inceptisols are found on floodplains……true?
yes
Inceptisols developed on floodplains can support the the cultivation of crops while those found in mountainous areas are ……..
often used for forestry, watershed and recreation.
………… are wet soils that contain high levels of organic matter.
Histosols
Histosols are often referred to as ……
peats
……….. are extremely weathered soils that occur in the tropical moist climate zones and under the tropical rainforest.
Oxisols
Oxisols are heavily leached. True or false?
True
……….are highly leached acid forest soils found in humid temperate and tropical areas of the world.
Ultisols
Without the use of fertilizer and lime, ultisols are poorly suited for continuous agriculture due to ……
high acidity and relatively low quantities of nutrients.
Soils with very high content of clay are called ……..
Vertisols
Vertisols often develop under …………..
savannah vegetation in tropical and subtropical climates.
Vertisols during the dry season ……….while in the wet season it is ………..
shrinks and deep wide cracks occurs, sticky and swells or expands
Vertisols look like they occur during…….
drought
When irrigation is available, vertisols can supports the cultivation of ……..
rice
This type of soil is moderately leached and is primarily found in temperate humid and subhumid regions of the world. What is it??
Alfisols
Alfisols develop under ……….
forests and moved forest-grassland
Alfisols are very productive soils for agriculture. True?
Yes
I have a light-colored E horizon and B horizon contains an accumulation of illuminated humus, iron and aluminum. Who am I?
Spodosols
Spodosols often occur under……
coniferous forest in cool moist climates.
Spodosols are ………and…….. in nutrients
acidic and low
Mollisols develop on ……..
loess, limestone and wind-blown sand
Mollisols are commonly found under ….
grassland vegetation
Aridisols are …..
dry soils with distinct horizon
Andisols are …….
young soils formed on fresh deposits of volcanic ash
……. are very fertile and support intensive cropping.
Andisols
Andisol areas are often used for the cultivation of …….
fruits, tea, maize, coffee, tobacco
………. are soils of extremely cold climates that contain permafrost within 2 meters of the surface.
Gelisols
Gelisols are commonly found in ……
Alaska, Canada and Siberia
PS; obviously found in cold regions
Low temperatures causes decomposition of organic materials to proceed very slowly in
Gelisols
Organic matter accumulates in the upper layer of gelisols giving it a ……………. color.
black or dark brown
Gelisols are very fertile. True?
No
Ghana Soil Classification System recognizes the following levels….
order, suborder, soil group family, Great soil group, great soil subgroup and soil series
Forest Oxysols are found under the …..
rainforest in South Western part of Ghana.
Forest oxysols are formed over wide range of highly weathered parent materials notably ……….
Granite, Tarkwaian and Birimian rocks.
Oxysols have matured profiles and their color ranges from……
brown to orange
Most oxysols are ……..
loamy and well drained
Organic matter content of Oxysols is lower than those of ………
forest ochrosols
Forest oxysols are ……..
strongly acidic
Forest oxysols are only good for the cultivation of acid tolerant tree crops such as ……
coconut, coffee, oil palm and rubber
Forest ochrosols are the main soils found under the ……..
moist semi-deciduous forest.
Forest Ochrosols are also going in portions of forest-savannah transition afro-ecological zones. True?
Yes
The characteristics of Forest Oxysols are similar to forest ochrosols. True or false?
True
Rainfall in regions with forest ochrosols are not as high as those with forest oxysols. True or false.
True
Ochrosols are not as highly leached as oxysols. True or false.
True
Forest ochrosols tend to contain higher quantities of nutrients and are also relatively less…..
acidic
Since Forest Ochrosols are relatively less acidic, what is the suitability for cultivation?
They are suitable for the cultivation of wide range of crops.
Common tree crops that can be cultivated on ochrosols are ……
cocoa, oil palm, rubber, and citrus.
Ochrosols can also support food crops such as ….
cassava, plantain, yams, maize
The term intergrade means ……
intermediate in grade
The Ochrosol-Oxysol inter grades occupy areas between the ……
Forest Ochrosol and forest oxysol
Rubrisol-Ochrosol intergrades are found within the ……..
forest ochrosol region
Rubrisol-ochrosol intergrades are among the best soils in Ghana. True?
Yes
Savanna Ochrosols are similar to forest ochrosols except……
they are found in savanna areas with semi-arid climatic conditions.
What is the main difference between Savanna ochrosols and forest ochrosols?
SO have less nutrient levels and are less acidic than FO.
Savanna Ochrosols can be divided into …..
Red and Yellow Savanna Ochrosols
Savanna Ochrosols are good for cultivation although their nutrient levels aren’t as high as the forest ochrosols. True or false?
True
Savanna Ochrosols are ………… acidic.
less
The bulk of Ghana’s food crops are grown on……
Savanna Ochrosols
The major factors that militate against crop production on Savanna Ochrosols are
low nutrients and moisture levels
The most extensive soil group in the interior wooded savanna zone is ……..
Groundwater laterite
Groundwater laterite cover about ……… of the interior wooded savanna zone.
75%
Groundwater laterites are developed over ………
Voltaian Shales and Granites
The cemented layer of ironstone below the the surface of ground water laterites is referred to as ……
Iron pan
Iron pan is a hard layer which makes it difficult for water to pass through the soil. True ?
yes
The color of soil in groundwater laterites ranges from……..
pale brown to pale grey.
Groundwater laterites are generally poor in nutrients and in…..
organic matter
The agricultural potential of groundwater laterite is ………..
limited by the abundance of iron pan
Crops cultivated on groundwater laterites are ……
millet, maize, groundnut and cowpea
Tropical Black Clays are also known as
Akuse soils
Tropical black clays are mostly found in …….
Coastal Savanna Zone.
Tropical black clays are developed over ……
basic gneiss in the Accra-Ho-Keta plains.
Tropical black clays are generally……during the rainy season.
wet and sticky
Tropical black clays become …….. in the dry season.
hard and develop wide cracks
Sugar cane and rice are the main crops on the ……
tropical black clays
Tropical grey earths are commonly found in the ……… of Ghana
coastal savanna zone
Topical grey earths develop in ……..slopes.
lower
Tropical grey earths consists of a thin layer of ………
grey sand overlying clay plan (very hard clay)
Tropical grey earths are similar to tropical black clays to some extent. The main difference is that …..
the grey soils are slightly acid
The topsoils of tropical grey earths are very low in nutrients and the subsoils which are richer in nutrients………
are not accessible to plant roots
Tropical Grey earths are mostly used as
open grazing fields
Sodium Vleisols are alkaline soils found in areas around …….
salty coastal lagoons and creeks of lower end of the Volta River
Sodium Vleisols are ………….in color
black or dark grey
Sodium Vleisols are clayey soils that necked sticky in the rainy season. True?
yes
Sodium Vleisols are not very suitable for crop production. True?
yes
Sugarcane is cultivated on ……..
sodium vleisols around the lower volta basin
Lithosols are …….
very shallow soils formed on steep slopes.
Lithosols have very little agricultural value. True?
yes
Alluviosols develop along the borders of ……
rivers and streams
The top soils of alluviosols are generally….
sandy, loamy or clayey
Sugarcane is also cultivated on alluviosols. False?
no
Alluviosols are locally used for ……
wetland rice
Organic matter content of oxysols are …… than those of forest ochrosols
lower
