soil’s main important uses for humanity.. 1. sand has higher percolation than soil 2. water will...
TRANSCRIPT
Soil’s main important uses for humanity.
1. Sand has higher percolation than soil2. Water will not leach right through, but give plants time to absorb. It also indicates that besides sand, there are components of silt and clay mixed in
3. Sand, then silt, then clay
1. Sand, then silt, then clay
2.
1. The plants are not able to absorb it, through bacteria and nitrification, unusable nitrogen is converted into usable nitrogen
Quantities of phosphorus in soil are generally small, it is often the limiting factor for plant growth.
3. Decomposition and weathering mineral from rocks
* A soil profile (soil horizon) describes a layer of soil with its distinct characteristics.
* Used to classify the soil and make interpretations
Soils-3-1Image: NRCS
Image: Martin Miller
Soil Profiles
Digging down into a soil, you would notice that the soil zone has a layered appearance. This layering is called a soil profile. Each layer of a soil profile is called a horizon.
Soil profiles vary between different types of soils, but one can often recognize the “O”, “A”, “B”, and “C” horizons in many soils.
Simplified Soil Profiles
a. Sandy loamb. Silt loamc. Sandy clayd. Clay loame. Clayf. Clay
2. pH can affect bacterial activity, decomposition rates, nutrient release, and plant growth.
4. 6.2-7.25. 5.5 to 7.06. Adding lime to the soil, manure, certain fertilizers A
D
CA
parent
C
parentC
B
A A
C
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1 3 2
B Ac
Soil Quiz
After Quiz• Read and notes 283-292.• Due on Blockday
The Rock Cycle
Erosion
Transportation
Weathering
Deposition
Igneous rock Sedimentary
rock
Heat, pressure
Cooling
Heat, pressure, stress
Magma (molten rock)
Melting
Metamorphic rock
Mechanical Weathering actions:– heating/cooling– freezing/thawing– glaciers– water– wind– plants & animals
Wind
Water
Chemical Weathering actions:• Oxidation takes place when oxygen
reacts with earth materials. • Hydrolysis is an exchange reaction
involving minerals and water. • Carbonic acid action• plants & animalsOxidation
Carbonic acid actionHydrolysis
Sand + Silt + Clay = 100%To find out Soil Texture (soil type)
Cation Exchange Capacity• The ability of a
soil to adsorb and release cations (positively charged mineral)
• Cations in the soil (Ca++, Mg++, K+ and Na+)
• In most soils, 99% of soil cations can be found attached to clay.
Soil: The Final Frontier• Soil is a vital part of the natural
environment. It influences the distribution of plant species and provides a habitat for a wide range of organisms.
• It controls the flow of water and chemical substances between the atmosphere and the earth, and acts as both a source and store for gases (like oxygen and carbon dioxide) in the atmosphere.
Ecosystem Services
Soil: The Final Frontier• Soils not only reflect
natural processes but also record human activities both at present and in the past. – They are therefore part of
our cultural heritage. – The modification of soils for
agriculture and the burial of archaeological remains are good examples of this.
Ecosystem Services
Without it, what would we do?• Soil helps to provide
much of the food that humans consume. – Only 25% of the Earth’s
surface is made up of soil and only 10% of that soil can be used to grow food.
• I.E., without soil, we cannot support primary producers.– By the way, they are the
base of the trophic levels!Ecosystem Services
Other Uses of Soil• Native North American
cultures used earth colors as body paints.
• Modern American culture uses colored earth in cosmetics and ceramics, antibiotics, and as pigments for paints.
Ecosystem Services
Porosity and Infiltration
Porosity• A measure of the amount of pore space between
grains; Porosity represents the storage capacity
Importance:• Higher porosity more
availability of oxygen (All plants need oxygen for respiration, so a well-aerated soil is important for growing crops)• Higher porosity more
availability of drinking
Percolation• rate at which a fluid moves into or through a rock or
soil.Importance:• determines if water
placed on soil will either soak through (so can be absorbed by plants)
• cause runoff • Or even worse
cause erosion.
Measure soil percolation rates at home:
• Dig a hole as wide and deep as a shovel head. • Fill the hole with water and note the time at which the hole is filled. • Note how long it takes for the water to completely disappear (i.e., 5
minutes, 30 minutes, 1 hour, etc.) • If the water is draining slowly, note how much water is draining each 30
minutes (i.e., 1/2 inch every 30 minutes). • Assess your results:• 0–4 minutes: You have fast-draining soil -plants will need to be watered
often unless they are drought tolerant. • 5–15 minutes: Soil drainage is good. • 16–60 minutes: Soil is fine. • Several hours/days: Very few trees will do well in this soil.
Soil Nutrition
Nutrients in Soil
• Nutrients are chemical elements and compounds found in the environment that plants and animals need to grow and survive. – Nitrate (NO3-), – nitrite (NO2-), – ammonia (NH3), – organic nitrogen (in the form of plant material
or other organic compounds), and – phosphates (PO4
3-)(orthophosphate and others)
MATTER CYCLING IN ECOSYSTEMS
• Nutrient Cycles: Global Recycling– Global Cycles recycle nutrients through the
earth’s air, land, water, and living organisms.– Nutrients are the elements and compounds
that organisms need to live, grow, and reproduce.
– Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.
Soil pH is a factor
• Soil pH (a measure of the acidity or alkalinity of the soil)
• Soil pH is one of the most important soil properties that affects the availability of nutrients. – Acids are detrimental to plant nutrition– Bases promote plant growth
The pH can be changed
• Lime can be added to the soil to make it less acidic and also supplies calcium and magnesium for plants to use. – Lime also raises the pH to the desired range of 6.0 to
6.5. In this pH range, nutrients are more readily available to plants, and microbial populations in the soil increase.
PondLittoral zone has soil where
rooted plants live (water lillies, cattails)
Aides in reducing erosion