Environmental Chemistry

Introduction
In this event, students are tested on their knowledge of soil properties and nutrients

The Competition
The 2009 event is a testing event with teams of 2 people. This is a lab event and the test consists of basic knowledge on soil, minerals, soil chemistry, soil horizons, and a lab testing part. The test may be taken in station format or a single written test taken at one table. Experiments may range from testing the pH of a soil sample, testing a soil for nutrients, and then making recommendations of what fertilizer should be added, density of soil particles, etc.

Parameters
A non-programmable calculator, pencil/pen, and 1 "8.5x11" sheet of handwritten notes on either or both sides PER STUDENT, may be brought to the competition.

Suggestions
Spend some time practicing testing soils for properties such as pH, N-P-K content, and moisture. You can find simple soil testing kits at Lowes or Wal-mart. You should know how particular nutrients help the plants. Example: Nitrogen promotes healthy, green leaves and growth of the plant. Know the major nutrients in soil (Nitrogen, Phosphorus, Potassium), the secondary nutrients (Calcium, Magnesium, Sulfur), as well as minor nutrients. Also, know how they help the plant (they all help in at least one way). Have an understanding of the different cycles (Nitrogen Cycle, phosphorous cycle, sulfur cycle, etc.) Know about substances that can be added to a soil to alter pH and other properties. (See section 14.2)

Sample Questions
1.Given a fertilizer label of 10-15-10, write the percentage of Nitrogen, Potassium, and Phosphorus

2.Given results of a tested soil, make recommendations of what fertilizers should be added to yield the largest amounts of vegetables like Corn.

3.Rate soil particles from smallest to largest. A.clay B.loam C.sand D.silt

4.Name two benefits of adding Lime to a soil. 5.Upon being given three soil samples, identify which is clay, silt and salt.

6.If my soil has a pH of 9.0, and I want it to be somewhere around 6.0-7.0, what should I add to it?

7.Define anion and cation.

Reading Fertilizer Labels
The key part of fertilizer label reading, is finding the quantity of the major nutrients. Somewhere on the bag there will be a line that looks like #-#-# [N-P-K] (With real numbers). These numbers signify the quantity of the major nutrients. It is based on how much of each nutrient would be in a 100-lb. bag. The first number represents the amount of nitrogen. The second number represents the amount of phosphorous. The third number represents the amount of potassium. So if a 100-lb. bag of fertilizer read 25-5-10, 25 pounds would be nitrogen, 5 phosphorous, and 10 potassium. The remaining 60 pounds are inert or inactive ingredients.

Plants
Environmental Chemistry has some plant questions as well, including pH and other growth concepts.

Soil Texture
You will need to know how to read a soil texture triangle. Remember that percentage of clay is read on the horizontal lines, left to right, percentage of sand is read from bottom right to top left, and percentage of silt is read from top right to bottom left. You will also need to know the size of the soil separates: Sand: 2.0 mm to 0.02 mm. Silt: 0.02 mm to 0.002 mm. Clay: Finer than 0.002 mm.

Plant Signs
Yellowing of leaves: upper leaves-lack of sulfer ; lower leaves-lack of nitrogen

Yellow spots on leaves: upper leaves-lack of iron ; lower leaves-lack of magnesium

Too much green(unnatural dark green) of leaves: lack of phosphorus

Blackening of edges on leaves: lack of calcium

Major Nutrients
Carbon (C): forms the backbone of plant bio-molecules, to include starch and cellulose. It is fixed through photosynthesis

Hydrogen (H): essential for the building of sugars and therefor the plant

Oxygen (O): necessary for the cellular respiration of the plant; O2 is the by-product of photosynthesis

Nitrogen (N): Nitrogen is especially important for the growth of the plant. Without it, the plant will have stunted growth. Plants with good amounts of Nitrogen will have strong roots and healthy foliage.

Phosphorus (P): Phosphorus plays an important role in photosynthesis. It helps in the formation of the plant's flower/seed. It also increases resistance to diseases. Without Phosphorus, Nitrogen could not so its job properly

Potassium (K): Potassium increases the plant's drought tolerance because it reduces water loss in leaves. Like phosphorus, it helps resist disease. It is responsible for water use to move nutrients. It assists in the ripening of fruits, especially grains.

Secondary Nutrients
Sulfur, Calcium, Magnesium

Minor Nutrients
Iron, Molybdenum, Boron, Manganese, Copper, Zinc, Nickel, Chlorine, Cobalt, Aluminum

A Plant's Favorite Level of Nutrition for each N-P-K
Heavy Nitrogen: leeks, potatoes, red beet, spinach, summer cabbage, winter cabbage, summer califlower

Moderate Nitrogen: squash, beans, lettuce, onions

Low Nitrogen: carrots, parsnips, radish, turnips

No Nitrogen: peas

Heavy Phosphate: lettuce, spinach

Moderate Phosphate: carrots, beans, onions, potatoes

Low Phosphate: brussel sprouts, peas, radishes, summer cabbage, red beet, turnips, summer califlower, leeks, parsnips

No Phosphate: winter cabbage

Heavy Potash: spinach

Moderate Potash: beans, leeks, onions, turnips, potatoes, red beet

Low Potash: brussel sprouts, carrots, summer califlower, summer cabbage, winter cabbage, lettuce, parsnips, peas, radish

No Potash: squash

Soil Contaminants
Are: Pb (lead) Ni ( Nickel) Hg (Mercury) Cd (Cadmium) Cr (Chromium) Other Heavy Metals

Soil Horizons
Something you may want to be familiar with are the different soil horizons. The main horizons are shown in the diagram below.



O: Organic matter. This is generally decomposing plant matter.

A: Surface Soil. Or topsoil. This is where plants will grow and obtain nutrients

B: Subsoil. This layer accumulates Iron, clay, Aluminum, and organic compounds through a process called illuviation.

C: Substratum. Accumulates more soluble compounds that bypass layer B.

Cation Exchange Capacity (CEC)
CEC is defined as the total amount of positive ions (cations) that a soil can absorb exchangeably.(negative ions are called anions) It is commonly reported in milliequivalents/100g dry soil. Basically, in a soil there are positive and negative charged nutrients. Positive charges lie on the top, for the plant to absorb. When all are used up, more cations must be added to "fill the void" so to speak. This may be a useful piece of information

pH
The pH scale is a logarithmic scale that goes from about 1 to 14. 1-6.9 is considered acidic, while 7.1-14 (or sometimes only to 12) is considered basic. A 7 is neutral, like distilled water. Most garden vegetables like slightly acidic soil (5.5-6.8). A pH of 3.2 is the pH of acid rain (sulfuric acid,) What makes things acidic or basic? Hydrogen ions (H+) make soil acidic. While OH- ions make a soil basic.

Determining pH
They are different ways to determine pH. One is using pH paper. When Blue pH paper is put in an acid, it will turn red. When red pH paper is put in a base, it will turn blue. If you use pH paper, here is a way to test your soil:

1.Mix your sample of soil with distilled water in a 1:5 ratio, soil:water.

2.Shake the mixture up and let it sit.

3.Once your mixture has settled, put in the pH paper and wait for a color to show up.

A second way is using Litmus paper. Litmus paper can turn a variety of colors when placed in the substance. Each color represents a certain pH number. To find out the pH, one would consult a scale. Lighter colors (oranges and reds) are generally acids, while cooler colors (blues and greens) are generally bases.

A third way is using universal indicator liquid. Placing a single drop of the liquid in a substance will turn it a certain color. Again you would consult a scale to determine the pH number.

A fourth way of determining pH is to use either an Analog or Digital pH meter. Simply place it in the soil for a couple minutes and read the pH number.

Altering pH
Certain substances can be added to either raise or lower the pH of a soil.

To raise pH (make more basic): Add Limestone, Lime

To lower pH (make more acidic): Add sulphur, Aluminum Sulfate, Ammonium Sulphate, Ammonium Nitrate

Periodic Table
It is a good idea to be familiar with the Periodic Table of Elements. You will see the Latin abbreviations of the Elements everywhere.

Periodic Table