I think both Kristen and I had our ups and downs in this lab, but overall it was an interesting and insightful experience. Needless to say I now know a lot more about soil than I had in the past (who would've guessed that dirt is different than soil?) and am glad to learn more about what I'm stepping on everyday. I for one never really thought about the fact that there are millions of microorganisms that live and function in the soil, hence making soil in fact alive. I also learned just what makes soil fertile and able to grow crops through all the labs and then in the remediation and controlled experiment labs. The labs helped me understand the fundamentals of soil and its various components.
People should be more aware of the dangers of soil overuse in agriculture. We use so much soil in agriculture nowadays and use the soil more than we're able to replenish it, and if we don't slow down our production and use it sustainably, we could end up not being able to feed large portions of the world. Although I was absent for most of the salinization lab, I know that the amount of salt we put into the soil can cause many problems for the soil and can cause it to lose its fertility. Like many of our natural resources, soil is a part of the environment we take for granted, and we are in serious jeopardy of losing it in the near future if we don't change our agricultural practices.
The lab was sometimes tiresome work, but I think it allowed us to learn about soil in an intriguing and effective way. And although sometimes I may still call it dirt, I'll know deep down that it is and always will be soil.
Also, I am responsible for the remediation, berlese funnel, soil fertility analysis, and soil porosity posts while Kristen is responsible for all the others.
Sunday, November 24, 2013
Kristen's Conclusion
This lab focused on the composition of
soil and tests that one can do to learn more about what is in the soil. Many
things can influence how well things grow in soil like whether it is clay or
sandy which influences water drainage. During this lab I have become more aware
of how much thought goes into different aspects of soil. Before this I did not
know that things like pH in soil mattered to the health of the soil and
organisms growing in it. I knew that soil had living organisms but I did not
know how influential these were in the development of the soil and how all the
different layers were made.The most important part of the
lab I think was learning how to test for different chemicals because it’s
important to know how much is already in your soil. As we learned earlier a lot
of the chemicals in soil like nitrogen and phosphorus are important in keeping
the environment healthy, and we need to use these sustainably. By knowing how
much the soil has you can tell how much is needed so that there isn't an excess
amount being used. I think it is important for people to know this along with
the benefits of using different fertilizers because paying attention to what’s
being put in your soil is something easy to do unlike some things like the
porosity which are more time consuming to figure out. Although organic is seen
as better it also has down sides because there's no way to know exactly what is
being put in the soil.
Salinization
In the salinization test we were assigned to create a bag of 4g/100mL concentration of salt for each lab table. Since we had to use 120mL of water we used the equation 4g/100mL=Xg/120mL to figure out the amount of salt we would need to keep the proportion the same. This came out to be 4.8g of salt so we mixed this in with 120mL of water. Then we put one paper towel with beans on top and poured 20mL of water into each of the 6 bags. In order to also compare red vs white beans we were to split up 3 bags of white and 3 bags of red beans. With our own bags we observed that the only growth was seen in the 0g of salt concentration bag. However, in other groups the .5g beans were also growing just as well and one group even had the start of a root breaking through in a 2g bag.
.5g concentration |
Overall, the higher concentrations were incapable of growing and most were even molding and had a green color to them. The same patterns in growth seen in the red beans were seen in the white beans.
This led us to the conclusion that things can not grow if there is too much salt. In order to remediate salty soils you can add sulfur, add carbon to reduce soil dispersion and the amount of sodium. Also tilling and leaching the soil can help.
white beans with .5g concentration |
Controlled Experiment
remediated (left) control (right) |
control (left) remediated (right) on the last day |
Remediation
Our soil was not exactly as fertile as we would have hoped. Through the results of our tests, we found that our soil was low on nutrients, organic matter, and life, which isn't extremely spectacular for growing crops, but it is also at a good neutral pH and a silt-loam complexion, which are more beneficial traits. So our focus for creating the best possible soil for our lettuce centered around adding more nutrients to the soil to support the plant's growth.
But first, we needed to decide exactly what traits we wanted to enhance in our soil. Looking at the tests we'd done on our soil, we found that because of the data from our berlese funnel test (there were no living organisms in our soil) we definitely needed to do something to create the best possible conditions for our plant to grow. We looked at the results from the soil texture tests and the percolation rate tests and found that the soil most likely has mostly a silt or silt-loam texture because the data from the qualitative and quantitative tests pinpoint a silt-like complexion and the data from the percolation rate test shows us that our soil was more similar to clay than sand but was not extremely close to that of clay. Our soil having a more silt-like texture was favorable in our opinion because we did not want the soil to be too sand-like or clay-like to detract from the growth rate of the lettuce, so we decided not to alter the soil texture. We also looked at the results from the percent organic matter test and correlated it with the soil fertility analysis to find that the low organic matter may be a factor of how low the soil's nutrients are. Organic matter contributes to the foundation of the soil's nutrients because without organic matter, the soil cannot take in as many nutrients and becomes less fertile.
Taking these results into consideration, we decided that it would be best to use inorganic fertilizer to give our lettuce the best chance of not being terrible. That doesn't sound super positive. I meant to say, to give our lettuce the best possible chance of being the best gosh-darn lettuce the world has ever seen! That's slightly better, maybe a little overdone, but let's keep this optimistic.
Anyway, because our lettuce has such low nutrient levels, we decided to use the inorganic fertilizer because we felt that it would be better to use specific known amounts of nutrients that would be added into the soil instead of organic fertilizer in which we'd have no idea the exact amounts of what we were adding to our soil. We didn't need to add anything to alter the pH because we thought a pH of 7 would be sufficient, we didn't add anything to the soil texture because we thought soil with mostly silt would be good for growing this type of seed, and we didn't add any more organic matter because we thought that adding more nutrients would be more helpful than adding more organic matter.
In our remediated soil, we added Vigoro fertilizer to add the essential nutrients we needed. The control soil weighed 262.7 grams and the remediated soil weighed 260.4 grams to begin the lab, and we appropriately added 12.8 grams of Vigoro into the water we used to water the remediated soil. We used 20 mL of water each day (except on days we were off school) to water the two plants, and we left the plants in natural sunlight each day.
We expect that the lettuce made in the remediated soil will be healthier and tastier than that of the controlled soil because of the nutrients added. Let's hope the remediated soil lettuce will be less terrible than the other. I'm sorry, I mean both of them will be fantastic, but maybe the lettuce with the enhanced soil will be even better!
The two variables (before adding fertilizer) |
Taking these results into consideration, we decided that it would be best to use inorganic fertilizer to give our lettuce the best chance of not being terrible. That doesn't sound super positive. I meant to say, to give our lettuce the best possible chance of being the best gosh-darn lettuce the world has ever seen! That's slightly better, maybe a little overdone, but let's keep this optimistic.
Stop! Hammer time |
The two variables (after adding fertilizer) |
We expect that the lettuce made in the remediated soil will be healthier and tastier than that of the controlled soil because of the nutrients added. Let's hope the remediated soil lettuce will be less terrible than the other. I'm sorry, I mean both of them will be fantastic, but maybe the lettuce with the enhanced soil will be even better!
Wednesday, November 13, 2013
Berlese Funnel
Our beautiful bottle of soil |
Looking good under the lamp |
When we were collecting the soil, we found some insects and worms that were in the soil, but somehow (as in through human error) we had none of these organisms in our soil sample. In particular, we saw earthworms in our soil when we collected it, and these organisms' function is to recycle nutrients and carbon in soil. We didn't see any other distinct organisms that were in the soil, but the worms do play an important role in the formation of soil.
No organisms :( |
Soil Fertility Analysis
Savio shaking his groove thang |
Phosphorous test |
pH test |
Potassium test |
Cuba Marsh |
Soil Porosity
We found our pore space to be 92mL because we had to pour 92mL of water onto the soil for the water to break the surface of the soil. To calculate the soil porosity, we needed to find the percent of the volume of dry soil that could be filled by water. In other words, soil porosity is the percent of the amount of open space in a given volume of soil compared to the total volume of soil.
92mL of water / 200 mL of soil = .46 x 100 = 46% porosity
Pour it up, pour it up |
The data showed us that there is in fact a lot of empty space between the solid matter that makes up soil in a given amount of soil. Almost half of the volume of our soil was composed of empty space that the water was able to fill. This also allows us to understand how harmful polluted runoff water can be to soil; if the polluted water is able to take up almost half the space of a given amount of soil, the water can do serious damage to the soil and the microorganisms within it.
Soil Dry Percolation Rate
Setting up the test |
To measure how fast water runs through dry soil we set
up three water bottles with the neck cut off and placed upside down in the
remaining bottle to act as a funnel. We set up three so that one would be used
for our soil, one for sand, and one for clay. The cross sectional area of our
bottle was about 9 pie centimeters. The numbers would make sense because clay
is able to absorb water more and slow down the rate at which water runs through
it, whereas with sand the particles are larger to where the water falls through
it more easily. Our numbers demonstrate this because in the clay the water
filtered through at a much slow pace of 0.06 mL/second and even then only 16 mL
of the water was able to filter through the clay because the rest appeared to
be absorbed. The sand had different results with 20 mL filtering through at a
rate of 0.21 mL/second. The sand had a faster rate and less water was absorbed
which further supported that clay absorbs more. As seen below, the percolation
rate of our soil at 0.19 was closer to the sand than the clay. This would
suggest that our soil was more similar to sand, although our past tests
somewhat contradict this belief.
Time Took Amount Drained
Sand 94.8 s 20 mL
Clay 269.4 s 16 mL
Soil 127 s 24 mL
after |
after (from left to right-soil,sand,clay) |
Percent Organic Matter
ooops |
The soil started at 28.1 grams after being
heated in the oven over night. We then placed the soil on the Bunsen burner, but
failed to put it in a crucible resulting in some possible errors in our
results. When we checked on our soil it had turned to a reddish brown color in
some places. Then the foil started to burn through so some of our soil fell
through which could affect the resulting mass. After the Bunsen burner the soil
weighed 25.6 grams, suggesting that 2.5 grams was lost as organic matter. This
number could have been higher than it should be since some of our
fallen soil could account for the difference in weight.
With the numbers we got 2.5 grams of the original total of 31.7 grams would
mean that about 7.8% organic matter was in our soil. It wouldn't be necessary to measure the mass alone because we are strictly looking at the difference in weight for this portion of the test. If the crucible was included in the first weight and then again in the second weight it would not effect the difference, or the grams that were lost as organic matter. We eventually would need a weight of only the soil, but since we already measured it for the soil moisture we can just use that as our original soil weight in order to calculate the percent of organic matter in our soil. One reason it is important to have organic matter is
because they supply the soil with nutrients such as nitrogen, phosphorus, and
sulfur. The organic matter also can absorb water which can be released to
plants, helping them grow. It also helps prevent erosion because of water
infiltration and the soil aggregation, which improves the soils ability to take
up and store water.
Soil Texture Test
Qualitative Test:
When performing this test I took about a handful of soil, a little smaller than the size of a ping pong ball, and added a few drops of water to the wad of soil until it was moist. Then, using my thumb and forefinger I squeezed it into a strand that was a couple of inches. Since I was able to at least form a short ribbon we ruled out the soil being mostly sand. However, since it was shorter we came to the conclusion that we most likely had silt or loam, because if it was clay the ribbon, theoretically, would have been able to be longer. Also the feeling of the soil helped us reach the conclusion of loam or silt because it felt a little sticky but not noticeably sticky so we thought it was mostly silt with maybe a little trace of clay.
Quantitative Test:
Before Shaking |
For this test we placed 70 mL of our soil
into a graduated cylinder and filled it with water to the 100mL mark. The soil
was originally a light dull brown but the water made it darker. After shaking
the apparatus and mixing the water and soil it formed a dark brown substance.
After leaving it out overnight the water again rose up above the soil leaving
only one distinct layer of soil. There was about 11 cm of a medium brown color
that had spots of dark color throughout and the water had become lightly tinted brown. Based on this calculation that 100% of
our soil was the same we would label it as silt. We also took into account our
qualitative test though which further strengthened our belief that we had silt
because of its ability to form a short ribbon. The small trace of clay that we
believed we had due to the ability to form a ribbon caused us to think that we
had about 10% clay and not the 0% that the quantitative would've suggested.
Therefore, for the clay and sand percentage we accounted for a very low 0-10%,
leaning more towards the 0% side for sand, and 10% side for clay. This left
about 85-90% to silt which based on our one layer seen in the test would make
sense. Based solely on the quantitative test we would have silt, however;
taking the qualitative test into account we thought it was more realistic that our
soil fell into the silt loam category. Looking at the triangle to the right you can see that
they met up at right around where the silt and silt loam categories meet (indicated by black dot),
suggesting it is somewhere within that range. This however somewhat contradicts
our percolation test outcome because since water took about the same time to
filter through our soil as it did in sand, and drained about the same amount of
water it suggests that our soil is more similar to sand than clay. Looking at
this test we would have expected a greater percentage of sand in our soil than
what we saw in our quantitative test. It was difficult to determine which areas were more likely to hold what soils because a lot of it varied and it was difficult to find accurate descriptions of the different areas and how they were developed since most were not necessarily well known or important places. Even our soil, which was from Cuba Marsh was hard to find because it is likely to have many types of soil because it incorporates many different types of land, with some of it being marsh and prairie, along with others.
after shaking |
After leaving out overnight |
Soil Moisture Test
Before putting our soil into the oven it
was a dull brown color and our sample weighed 31.7 grams. After removing it
form the oven it looked more crumbly and hard. It weighed 28.1 grams, meaning
that about 3.6 grams of the original soil was water. With 3.6 grams of a total
of 31.7 grams as water that would mean that about 11.35% of the soil was water.
This goes with our texture results because based on our texture we figured it
wasn't as moist as clay but it was not as dry as sandy soil. Since our moisture
was a little less than average for soil it would confirm our findings of our
previous tests that it is somewhere in between. Based on our soil and other groups' soil we felt there is a correlation because usually if the
texture is more smooth and clay like it will also be more moist than a sand
texture that is gritty and tends to be a little more dry. This proved true because we found that the groups that had clay had more water in their soil than we did. One of the groups that had clay had almost 5 times as much moisture as we had.
Monday, November 4, 2013
Collecting Our Soil
We collected our soil from Cuba Marsh. The soil was difficult to get a lot of because once we reached 12 inches deep, we noticed it got more grainy, and it was harder to scoop up the particles. We mostly noticed roly polys and rocks in the soil which was covered by grass and leaves. The soil looked dry and was a light brown. The particle sizes were mostly smaller particles but there were also a lot of clumps. There was a walking path and a lot of trees in the area. The path could effect our results since it means that part of the area has clearly been altered by man. To try and
avoid this we picked a spot away from the path.
avoid this we picked a spot away from the path.
Before |
Savio hard at work |
After |
Introduction
Components of soil |
Illinois Drummer Soil |
Georgia Tifton Soil |
Arizona Soil |
Hawaii Hilo Soil |
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