7.1 Discuss salinization, nutrient depletion and soil pollution as cause of soil degradation.

Slides:



Advertisements
Similar presentations
Certain types of bacteria indicate animal and human waste pollution.
Advertisements

Water Quality Indicators.
Phase Diagram for Water
Soil Fertility and Nutrient Bioavailability Sponsored by the DEST program China Higher Education Strategic Initiatives © The University of Adelaide.
ECDCICA - CYCLES MATTER MUST CYCLE.
Greenhouse Crop Management Sheila Dunning Commercial Horticulture.
The Punic Wars –Case for Salt in Soils “After the third punic war, the Romans stormed the town and the army went from house to house slaughtering the inhabitants.
Interest Approach Collect samples of growing media. Some suggestions are water, sand, peat moss, gravel, garden soil, potting mix, etc. Have the students.
Cycling of Matter. Recap: Environment: all abiotic and biotic factors that exist on Earth as well as their interactions Abiotic: non-living factors Biotic:
Plant Environment Fertilizers and Plants. Objectives  Determine the roles of plant nutrients for plant growth.  Describe the effects of external factors.
Biogeochemical Cycles
Mineral Nutrition and Transport in Plants (Pages )
Soil Chemistry Chapter 5.
E NVIRONMENTAL CHEMISTRY E 12. water and soil. W ATER AND SOIL Solve problems relating to the removal of heavy- metal ions, phosphates and nitrates from.
ALL ABOUT SOIL.
Assessing Aquatic Ecosystems & Measurement. Aquatic Ecosystem Assessment The health of an aquatic ecosystem can be determined by examining a variety of.
Ocean Water Salts and Gases.
Environmental chemistry
 carbon (C), hydrogen (H 2 ) and oxygen (O 2 ).  Mainly present in water, (absorbed through leaf and roots from ground and atmosphere). The other source.
Cell Nutrients Nutrients required by cells can be classified in two categories: - are needed in concentrations larger than M. C, N, O, H, S, P, Mg.
Marine Water. n Marine waters may be fully saline, brackish or almost fresh. Marine habitats include those below spring high tide limit (or below mean.
Composition of Ocean Waters. Salts and Salinity Ions Ions are stable forms of elements that acquire an electrical charge by gaining or losing electrons.
Soils & Plant Nutrition Rodney Pond PhD Student School of Environmental and Forest Sciences.
SEAWATER and the properties of the water molecule.
Seawater Chemistry.
Biogeochemical cycles How matter cycles through systems.
IV. Water Chemistry A. pH, hardness, and other ionic compounds and gases affecting water quality.
Soil. What is soil?  Mixture of inorganic material (rocks) and organic material (SOM) as well as organisms (microbes).  Soil formation involves:  Parent.
How soils supply plant nutrients An Introduction to Soil Chemistry
Ecological Cycles Biosphere Carbon cycle Phosphorus cycle Nitrogen
Soil Discuss salinization, nutrient depletion and soil pollution as causes of soil degradation. Describe the relevance of the soil organic matter (SOM)
Soil  Discuss salinization, nutrient depletion and soil pollution as causes of soil degradation.  Describe the relevance of the soil organic matter (SOM)
Media and Soils Chapter 6.
RIVERS: Major Components 1) water 2) suspended inorganic matter - major elements are Al, Fe, Si, Ca, K, Mg, Na and P 3) dissolved major spp. - HCO 3 -,
CHEMICAL OCEANOGRAPHY
Physical Oceanography Section 2: Seawater
SOILS AIR, ORGANISMS, NUTRIENTS BY : NEKAISHA LEGERTO N.
CHAPTER 2 CHEMISTRY OF LIFE. 2-1 The Nature of Matter.
Surface Chemistry. Topics 1.Soil Minerals 2.Soil Adsorption Phenomena 3.Interaction of Water – Clay Minerals 4.Inorganic and Organic Solute Adsorption.
Chapter 5 Weathering and Soil
Environmental Aspects of Food Production page 13.0.
Water Chemistry Notes Mr. Distasio. Carbon Dioxide (CO 2 ) Colorless, odorless gas Source: Respiration Removal: Photosynthesis Highest Levels: at night,
Soil and Plant Nutrition
Salinity is the total amount of dissolved salts in water; grams of salts per kilogram of water (g/kg) or as parts per thousand (ppt). Seawater has 11 major.
Properties of seawater. Properties of water 1.Polarity and hydrogen bonding cohesion good solvent many molecules dissolve in H 2 O 2.lower density as.
III. Cycles of Matter *While energy is crucial to an ecosystem, all organisms need water, minerals, and other life-sustaining compounds to survive. In.
6.1 Section Objectives – page 141 Relate the structure of an atom to the identity of elements. Section Objectives: Relate the formation of covalent and.
Soil : soil degradation Salinization  Salinization is the result of irrigating soils i.e. watering them. Water used for irrigation usually contains dissolved.
ORGANIC MATTER DECOMPOSITION
Ocean Properties and Chemistry
 Total amount of salts dissolved in seawater  Salinity is expressed as the number of grams of salt left behind when 1,000 grams of seawater are evaporated.
Chemistry of Life Life Science Book pp The Importance of Food Living things need food for building tissue and for energy. What is not used is eliminated.
Soil : soil degradation Salinization  Salinization is the result of irrigating soils i.e. watering them. Water used for irrigation usually contains dissolved.
Seawater Chemistry JQ: If you add a pinch of salt to water, will it boil faster?
Intro to Minerals. What is a rock? A consolidated mixture of minerals.
Cycles of Matter. Earth is a closed system Living organisms need matter to cycle because they are crucial for energy and structural building blocks.
Salinity HYDROLOGY INVESTIGATION Oceanography Chapter 7 Salinity.
SOIL REACTIONS, SOIL ACIDITY SOIL ALKALINITY, CONDUCTIVITY, REDOX POTENTIAL.
FERTILIZERS, CHLORINATION DEODORIZERS, BACTERIAL FORMULATION.
71% of the Earth’s surface is covered by oceans. The oceans contain more than 97% of the planets water Only 10% has been explored by humans. The average.
LESSON TOPIC: The Inorganic Chemistry of Water
Water – The Liquid of Life
Nutrients and Soil Organic Matter for Crops: Care for these RESOURCES
Environmental Chemistry
Chapter 8 The Nature of Water
Resources and Our Environment
Soil.
Chapter 4 Section 2.
Introduction to the Oceans
Presentation transcript:

7.1 Discuss salinization, nutrient depletion and soil pollution as cause of soil degradation

Where does it come from?  Physical means Weathering of rocks ○ CaCO 3 + H 2 O + CO 2 -> Ca HCO 3 -  Chemical means Bacteria and fungi in the soil breakdown organic matter which then makes more soil

Components of soil  Inorganic matter Largest component From weathering of rocks Contains ○ Silica ○ Silicates ○ aluminosilicates  Water/ Air The amount affects how life forms survive and then decay  Organic matter Bacteria and fungi convert organic matter into humus ○ A water insoluble mixture ○ Half it’s mass is carbon and approx. 5% nitrogen

Inorganic Matter  Silicates Silicon is covalently bonded to four oxygens  Aluminosilicates Al 3+ has a similar size to silicon Can replace the silicon to form aluminosilicates

Inorganic (cont’d)  If Al3+ replaces a Si 4+ then in every four tetrahedrons there is 1 electron deficient  These ions + electronegative oxygen = ability to hold onto plant nutrients  Plant nutrients K + ○ Controls the amount of water that enters via osmosis NH 4 + ○ Synthesis of amino acids and proteins Ca 2+ ○ plant cell wall synthesis Mg 2+ ○ Synthesis of chlorophyll

7.1 Salinization  Accumulations of water soluble ions or salts in the soil due to continual irrigation to crops  How? Small amounts of salts ( CaCl 2, MgSO 4, NaCl) are in water When irrigation doesn’t wash them away they build up in the soil

salinity Salinity is the total amount of dissolved salts in water; grams of salts per kilogram of water (g/kg) or as parts per thousand (ppt). Seawater has 11 major constituents that make up more than 99.99% of all dissolved materials. Although salinity may vary, the major constituents are well mixed and present in the same relative proportions.

Salts  Chloride (Cl - )55.07%  Sodium (Na + )30.62%  Sulfate (SO 4 2- )7.72%  Magnesium (Mg 2+ )3.68%  Calcium (Ca 2+ )1.17%  Potassium (K + )1.10%  Bicarbonate (HCO 3 - )0.40%  Bromide (Br - )0.19%  Strontium (Sr 2+ )0.02%  Boron (B 3+ )0.01%  Fluoride (F - )0.01%

Salinity  Affects other properties of seawater, such as its density and the amount of dissolved oxygen.

Salinity  Significant Values The average salinity of the world’s oceans is 35 ppt. Freshwater has a salinity of <1 ppt. Inshore waters with salinity values between ppt are called brackish. Waters with salinity greater than 40 ppt are called hypersaline.

Salinity Addition of salts to pure water causes an increase in density. Salinity can be calculated by measuring the specific gravity of a water sample using a hydrometer, correcting for the effect of temperature and converting the readings to salinity by using conversion tables. Specific Gravity = density of sample Density of pure water

Salinity  Be sure hydrometer is clean  Fill 500 mL graduated cylinder with sample water  Determine the temperature of your sample  Place the hydrometer in cylinder and let settle. It should not touch the cylinder walls, and should be read from the bottom of the meniscus.  Read the specific gravity from the hydrometer scale  Using the specific gravity and temperature values, determine salinity from salinity table in Teacher’s Guide  Read three times. The values should be within 2 ppt of the average. Discard outliers.

Calibration 35 ppt standard: ○ Measure out 17.5 g NaCl (table salt) and pour into a 500-mL graduated cylinder. ○ Fill the cylinder to the line with distilled water and carefully swirl the solution to mix the standard, until all salt crystals have dissolved. ○ Pour the solution into a 1-quart plastic bottle and label. Prepare a blank using 500 ml of distilled water. Follow the directions for a water sample. Check technique every six months.

Salinization

How?  Bad irrigation Small amounts of salts ( CaCl 2, MgSO 4, NaCl) are in water When irrigation doesn’t wash them away they build up in the soil  Rise of the water table Removal of native plants which leaves to reduction in evapo-transpiration ○ Soil water gets close to the surface and evaporates leaving behind the salts

Salinization Effects  Reduces plant growth Increase in ions means a decrease in plants ability to take up water Osmosis is affected ---Suggested experiment: effect of time, temp., size of seed, type of soil, water

Nutrient Depletion  Decreases soil quality = decline in crop yield  How? crops that take nutrients and minerals from the soil and are continually harvested reduce soil quality

Countering Nutrient Depletion  Replenishing minerals and nutrients  Crop rotation  Nitrate/ Phosphate fertilizers Chemicals end up in water supply ○ Leads to eutrophication (excess growth of aquatic life)

Soil Pollution or Contamination  Due to pesticides, herbicides, fungicides Pesticides = kill insect pests ○ Lower crop yields – destroy flora/ fauna ○ Pollute ground water Herbicides = kill unwanted plants or weeds Fungicides = controls fungi

Soil Contamination  Nitrogen/ Phosphate fertilizers  Domestic/ industrial waste Contain heavy metals (chromium, copper, mercury, lead, zinc) Organic contaminants (PCBs, PAHs)

PAH

7.2 SOM  Soil organic matter The mixture of non-living organic components present in the soil in various stages of decomposition arising from the chemical and biological action on plant matter and organisms

SOM  Amount of carbon in the soil is a measure of the organic matter present Can be tested through titration using a dichromate(VI) solution

SOM (cont’d)  Contains Humic substances ○ Contain phenolic acid (ArOH) and carboxylic acid (RCOOH) functional groups; weak acids RCOOH RCOO - + H + The anion RCOO - binds to plant nutrients Sugars Amino acids High molecular mass polysaccharides and proteins

Carboxylic acid  Anion:  Chelate to plant nutrients  Ca 2+ Fe 2+ Mg 2+ Ca 2+  Zn 2+ Mn 2+ Co 2+  Al 3+ > Mg 2+ > K  Higher the charge density, stronger the binding

Chelate

Polysaccharides

polysaccharides  Commercial astragalus extracts have been standardized to 40-50% polysaccharides;  some sources claim ability to provide 70-90% polysaccharides.

Phenolic acid

Carboxylic acid

Nylon

Relevance of SOM in Preventing Soil Degredation  Plays important role in soil quality  Deserts (SOM= Sweet soil) Organic matter + sand = improved plant growth  Holds onto water  Improves soil structure  Reduces soil erosion  E12.4 chemical function

SOM: Biological  Binds to nutrients – used by microbes and for plant growth  Bacteria and fungi decompose SOM  SOM Has large amounts of Nitrogen 5% ○ Synthesis of proteins and chlorophyll Phosphorus ○ Synthesis of enzymes and storage of energy Sulfur ○ Synthesis of amino acids

SOM: Mineralization /ongoing process  Organic matter that contains nitrogen and phosphorus is broken down or mineralized to release nitrogen and phosphorus to the root  N, P, K, S

SOM: Physical  Allows stable forms of soil clusters Reduces soil erosion Increase water retention properties Increases ability of air/ water to move through soil  More water affects thermal properties Moist soil has a higher heat capacity than dry soil Aka more water = smaller temperature change