Nitrogen, Phosphorus, Potassium and pH Tests

Nitrogen, Phosphorus, Potassium and pH tests:

     For both the Nitrogen and pH tests, we had to mix small amounts of soil with solutions to determine the pH of the soil and how much Nitrogen was in the soil. We had very small amounts of or no nutrients in our soil. For the Nitrogen, we concluded we had trace elements of Nitrogen. Unfortunately for the future of some of the lettuce seedlings in our care, the Phosphorus levels appeared to be trace to none as well; with the Potassium being only slightly higher in abundance. For the pH, we determined the pH is between 6.0 and 7.0 (relatively neutral). The Phosphorous had trace amounts (about 0 lb/acre) and the Potassium took 18 drops to make the solution blue. This means that it had low amounts of Potassium or about 0-120 lbs/acre.
      In the area that we collected soil, we found wild strawberries beginning to grow. Strawberries can be grown best in 6.0 pH, but they can be grown in a wide range of soil pH. The plants looked relatively healthy even though our tests concluded that there was absolutely no nutritional value in the soil other than low amounts of potassium.

Percent Organic Matter Test:

For this test, our soil sat overnight in an oven to evaporate all of the moisture out of it. It was then placed in a crucible and weighed 83.5 grams. The crucible then sat above a bunsen burner in order to burn off all of the organic matter. It is lost due to the conversion of organic matter to carbon dioxide and water at high temperatures. After about 30 minutes of being heated, the bunsen burner was turned off and the crucible left to cool. Five minutes after it was cooled, we went to weigh the new mass. However, we spilled the soil and human error is not accounted for in our calculation of organic matter in the soil. The end mass, 73.1 grams give or take a few then lets us calculate the percentage to the best of our ability.

(83.5 grams - 73.1 grams)/ 83.5 grams = ~12.5% organic matter

 It is not necessary to measure the mass of the soil alone because the mass of the crucible never changes. It is the same in the beginning as in the end and you are not testing the mass of the soil, but the change in mass from beginning to end. It is important to have organic materials in the soil because having organic materials improves the infiltration of water and air by increasing pore space. In addition to it helping with the pore space of the soil structure, it also loosens soil making it easier for plants to spread their roots. A second reason why organic matter is important is because it increases water capacity. It is said to be that organic matter is 1,000X more absorbent than just plain minerals. A third and final reason why organic matter is important is because it adds nutrients to the soil. Without natural nutrients, most plants would not be able to grow without man-made fertilizers. These nutrients are released into the soil as organisms in the soil digest and decompose their "food" or organic matter.

Soil Texture Test:

Qualitative Test- For the qualitative test, soil was mixed with a small amount of water and mixed in Martin's hand. Once the small ball of soil was formed, the soil was found to feel sticky. This means that it is mostly clay. We were also able to form a small, short ribbon out of the soil. This determines that the soil is a silt or loam. By putting together the fact that our soil is mostly clay and was able to form a short ribbon, we can conclude that our soil is a silty clay loam.

Quantitative Test- For the quantitative test, 70 mL of soil was placed in a graduated cylinder with approximately 35 mL of tap water. We shook the mixture for about one minute and then left it over night to settle. After all of the components settled, it was determined that the mixture held 0 mL of sand , 60 mL of silt, 7 mL of clay, and 30 mL of organic matter/water (about 2 mL of organic matter). Overnight about 3 mL of water evaporated.

60 mL of silt/ 70 total mL of soil = 86% silt

7 mL of clay/ 70 total mL of soil = 10% clay

2 mL of organic matter/ 70 total mL of soil = 3% organic matter

0 mL of sand/ 70 total mL of soil = 0% sand

To account for the missing 1%, we can assume it was the moisture in the soil that either evaporated with the water or combined with the overall water originally added to the mixture.

According to the Soil Textural Triangle, our soil is silt. This is different than what we discovered in the Qualitative Test, silty clay loam. The difference in percentage of clay was 20-30%, the difference in percentage of sand was 10-20%, and the difference in silt was  30-40%. 

The data from our dry percolation test states that our soil drained 28 mL of water in 13.2 seconds. Clay drained 40 mL of water in 12.8 seconds and sand drained 18 mL of water in 18.5 seconds. This shows that our soil behaved more like clay than it did sand. This was proven true when we determined our soil had 0% sand and about 10% clay.
In comparison to Melissa Goldberg's soil, they are very similar. Both have 10% or less of clay, 90% of silt, and little to no sand. Melissa's group collected soil from a forest in her partner's backyard. Both soils were found in forests (ours was from Cuba Marsh). Kristen and Michael also got their soil from Cuba Marsh. There results also showed a sticky clay-like texture and was determined to be silt or silt loam in both the qualitative and quantitative tests. We believe that the soils are similar in texture because they are both meant to support trees. This is likely because silt is very rich in nutrients and helps plants grow. For those reasons, silt is considered a natural fertilizer.

Collecting Dirt!

     After being introduced to our purpose, our somewhat legal adventures took us to Cuba Marsh Forest preserve in search of our treasure- dirt! or soil, as Mrs. Cohen would prefer. We found an area in a forest which had dirt that looked relatively undisturbed, and took enough of it (12 inches deep) with a trowel to fill a one gallon plastic bag at least halfway. The soil was of a relatively dark color, with background knowledge indicating that it should have high clay content. The soil collected had few stones, but a good amount of clumps where the generally soft soil had combined with itself. There was much plant life in the area, but no buildings and only a gravel pathway nearby, meaning we should have relatively nice dirt in that plastic bag. Be sure to stick around for more dirt-filled feats and escapades!




--sorry Ms. Cohen I cannot figure out how to rotate pictures.

Introduction:

Around 45% of soil is composed of mineral matter, 25% is air, 25% is made of water, and the remaining 5% is organic matter. The difference between soil and dirt is that soil is alive and dirt is dead. Soil is formed through five factors:
1- Parent Material: mineral and organic matter
2- Climate: weathering breaks down the parent material
3- Living Organisms: plants and animals decompose adding nutrients to the soil
4- Topography: whether or not the landscape is flat or sloped
5- Time: creating soil takes many, many years
When examining texture, you look at how much sand, clay and/or silt is in the soil. You also check to see if the soil is loamy or not. The color of the texture tells you all about the soil's history, richness, and composition. pH will tell you whether or not the soil is too acidic or too alkaline. This is important to know because certain plants/crops can only grow in certain pH levels. For example, blueberries can only grow in very acidic soil. The structure of the soil is the arrangement of solid clumps and porous space located between them.

Most soil in Illinois is called Drummer soil. It is a thick silty clay loam. This means it is composed of 0-30% sand, 40-60% silt, and 30-40% clay. In Hawaii, the soil is called Hilo and is a silty clay loam composed of relatively the same percentages as Illinois. The difference though is in color. Illinois is a grayish brown whereas Hawaii's soil is a dark brown. In Georgia, the soil is called Tifton. Tifton is a loamy sand composed of 10-15% clay, 0-30% sand or silt. Arizona soil is called Casa Grande. It is a  saline-sodic fine sandy loam. This means it is composed of 50-70% sand, 0-30% silt, and 0-20% clay. 
There are many reasons for farmers to want to analyze the soil. Economic benefits from soil analysis include being able to grow the crops themselves. Crops can only be produced in certain soils suited to them, and without planting them in the right plants, farmers would not make good tasting foods. If their crops did not taste good, no one would buy them and then they would not make a profit. A second benefit of soil analysis is the crop rotation or cover crop usage. If the soil is good for the main crop grown, then it must also be good for the crops used in the crop rotation or the cover crop. If the soil cannot support all the crops necessary, then the nutrients in the soil will be depleted in a short period of time and the farmer cannot grow any more crops. This then causes him to lose profit. A social benefit of soil analysis is being able to sustain for the population. Without farmers being able to produce food, humans would have no way of staying alive. This is especially important due to the increasing population in many countries. For example, Mexico's population is rapidly increasing and without farming techniques and determining what crops can be grown where, they will not be able to provide food for all of the inhabitants. Another social benefit is the ability to provide jobs. If a farmer did not test the soil, he or she could attempt to grow crops in an area not suited for farming. If this occurred, the farmer would realize shortly after that they cannot grow crops and must fire all of their employees. However, if a farmer tested the soil, he or she would know the soil is good for farming and be able to provide jobs for people in the long run. This is ties in with the growing populations and more people needing jobs. This is also an economic benefit because the more one makes, the more one is likely to spend.