Soil Flashcards
is the loose surface material that covers most land. It consists of inorganic particles and organic matter.
provides the structural support to plants used in agriculture and is also their source of water and nutrients.
Soil
what are the different types of Soil?
Clay, Loam, Sand, Silt
is soil that is comprised of very fine mineral particles and not much organic material.
Clay
is light, warm, dry and tends to be acidic and low in nutrients.
Sand
a solid, dust-like sediment that water, ice, and wind transport and deposit.
Silt
is ideal for most garden plants
Loam
How was soil formed?
It is formed by the combination of physical, chemical and biological processes in which huge rocks are broken down into smaller particles over a long period of time.
It forms the foundation of terrestrial life on Earth.
Pedosphere
is the upper layer of the topsoil which is mainly composed of organic
O horizon
is rich in organic material and is known as the humus layer. Seed germination takes place in this layer.
A horizon/topsoil
composed of nutrients leached from the O and A horizons
E horizon/eluviation
the subsurface horizon, present just below the topsoil and above the bedrock. It is comparatively harder and more compact than topsoil.
B horizon/subsoil
This layer is devoid of any organic matter and is made up of broken bedrock.
C horizon/ saprolite
It is a compacted and cemented layer.
R horizon/ bedrock
Layers of soil
O horizon
A horizon/top soil
E horizon/eluviation
B horizon/subsoil
C horizon/saprolite
R horizon/bedrock
Soil is composed of…
45% mineral particles
5% organic matter
25% water
25% air
Organic - animal manure, bone meal, compost (slow- acting, long-lasting)
Delay in availability to plants, needs time for the organic material to decompose
Delay causes low level of nutrient
Improves water holding capacity
Soil nutrients (NPK)
Roles of soil nutrients
N- needed for production of amino acids/proteins; important for photosynthesis
P- important component of nucleic acids (transfer of genetic info) phosphoproteins and phospholipids.
K- enzyme activator that allows stomates to open and close and water vapor and oxygen to move in and out of plant cells
Most soil ranges from 4 to 8
At a low pH, the aluminum and marn more manganese in soil water are the roots absorb them in toxic concentrations.
Certain mineral salts essential for plant
growth, such as calcium phosphate, less soluble and less to plant at a higher pH.
Soil pH
volume of water that “fits between” the soil particles
Porosity
rate of flow of water through soil
Permeability
how much water is “trapped” by soil
% retention
Porosity and Permeability are (directly or indirectly) related;
Directly
refers to the contamination of soil with abnormal concentrations of toxic substances
Soil pollution
What are the causes of soil pollution?
Manmade
Natural pollutants
Degradation of land in arid and semi-arid regions due drought and overgrazing. Results in loss of biodiversity and loss of productive capacity
Desertification
Soil degradation caused by over irrigation: irrigated water contains salts that, when water evaporates are left behind
Salinization
Problem associated with excessive irrigation on poorly drained soils where water can’t penetrate deeply. When soils are water logged, air spaces in the soil are filled with water, and plant roots essentially suffocate - lack oxygen.
Water logging
2 categories of soil degredation
Erosion
Physical and chem deterioration
is a set of farming techniques and practices to avoid degradation, erosion and depletion. Soil conservation methods target long-term use with a thought of the future. By taking proper and timely actions
Soil conservation
This one of the methods using soil conservation that Roots of trees firmly hold on the soil making it stagnant and prevent soil erosion.
Tree planting
A terrace is a leveled section of a hilly cultivated area. Terracing gives the landmass a stepped appearance thus slowing the washing down of soil
Terraces building
Is a cultivation technique in which the soil is disturbed only along the slit or in the hole into which the seeds are planted
No tilt farming
It is the method of plowing across the contour lines of a slope
Contour plowing
is the practice of planting different crops sequentially on the same plot of land to improve soil health, optimize nutrients in the soil.
Crop rotation
Soil pH is an indicator of the level of nutrients in soil. The uptake of nutrients by plants also depends on the pH of soil.
Maintaining soil pH
Watering soil is a good measure of soil conservation.
Water the soil
Managing salinity involves striking a balance between the volume of water entering (recharge) and leaving (discharge) the groundwater system
Salinity management
Nitrogen-fixing and denitrifying bacteria are important constituents of the nitrogen cycle.
Promote helpful soil organisms
Methods of soil conservation
Tree planting
Terraces building
No till farming
Contour plowing
Crop rotation
Maintenance the soil pH
Water the soil
Salinity management
Promote helpful soil organisms
