| testing_soil_productivity.doc |
Hannah Kyer
Caitlin Rauchle
2-3-10
Testing Soil Productivity
Introduction:
There is a wide variety of soil types depending upon the environment. Some soils have characteristics that make them arable, meaning that they are able to grow crops well. Characteristics that determine a soil’s ability to grow crops include water-holding capacity and capillary action, ion exchange capacity, plant nutrition and soil minerals, pH, and permeability. The soil that was tested in this lab experiment was loam farm soil from Charlottesville, Virginia. Loams are a mixture of sand, clay, and organic material and are slightly to strongly acidic.
The purpose of this lab experiment is to create three soil types (good, bad, and control) from the original Virginia farm soil by adding sand, clay, and/or humus to the soil. The level of productivity of each soil type will be tested by planting alfalfa seeds in each soil and, once the alfalfa seeds have sprouted, finding the biomass produced from the alfalfa seeds produced in each of the soil types. To find which soil (clay, humus, or sand) should be added to the Virginia soil to make it worse or better for growing crops, properties of the Virginia farm soil such as water-holding capacity and capillary action, ion exchange capacity, plant nutrition and soil minerals, pH, and permeability must be tested.
If the Virginia farm soil is tested for its water-holding capacity and capillary action, ion exchange capacity, plant nutrition and soil minerals, pH, and permeability, then it will be determined that to make the Virginia farm soil more arable, humus must be added to the soil because it has good permeability and to make the soil less arable, sand and clay must be added because sand is very impermeable and clay has a low ion exchange capacity. The independent variables for this lab are the types of soils that the alfalfa seeds are planted in (good, bad, or control) and the dependent variable is the biomass of alfalfa produced from each soil type. Variables that must be held constant for all three soil types include the amount of light and water the plants receive and the temperature that the plants are exposed to.
Procedure:
First, we separated half of the original unknown soil sample and set it aside. This half would be the control group soil. We then divided the remaining quantity of soil in half (about one quarter to one half mixing cup for each pile). These two piles would be the testing samples. We then looked over the results of each of the soils regarding their level of permeability, ion exchange, water-holding capacity, etc. Next, we acquired three strips of plastic pots. Each strip contained four pots. In the first strip of four pots, we filled each of the four pots with the original Virginia soil sample.
Based on the results from testing the original sample, we determined that to create a soil that would grow plants better than the original Virginia soil sample, humus would have to be added because it had good permeability, ion exchange capacity, water holding capacity, etc. We filled each of the four pots in the second strip of pots halfway with the Virginia soil sample and the rest of the way with humus. To create a soil that will not grow plants as well as the original Virginia soil sample, we filled each of the four pots in the last strip of pots halfway with the Virginia soil sample and the rest of the way with sand and clay because clay is very impermeable and sand has very low ion exchange capacity. We then marked each strip with they type of soil it contained (good, bad or control). Next, we counted out 30 alfalfa seeds to each pot and gently pressed the seeds under the surface of the soil. We then added 20 mL of water and placed all the pots in an area with ample light. 20 mL of water was added to the soil every day for 6 days. The amount of light and water the pots received and the temperature each pot was exposed to was the kept the same for each pot. After the 6 days, the alfalfa sprouts were taken from the soil and dried, making sure that the alfalfa plants from each soil type were kept separated. Once all of the water had been taken out of the soil, the alfalfa was weighed to find its biomass.
Data Analysis:
The results show that the good soil produced the most biomass, the bad soil produced the least biomass and the control (the original soil sample) had a medium amount of biomass. This suggests that the good soil (the mixture of Virginia soil and humus) was the most productive and the bad soil (the mixture of Virginia soil, sand, and clay) was the least productive of the three types of soils. Although the good soil was the most productive and the bad soil was the least productive, the difference in biomasses between the soil types was very small. The small difference in biomasses between the three soil types could be due to sources of error. Possible sources of error include if not all the soil received exactly the same amount of water, if some seed were not planted correctly and therefore never sprouted, and if some pots contained more soil than others. These errors could alter the results and make some soils produce more alfalfa while other soils produced less alfalfa.
This lab was fairly reliable because four tests were conducted for each soil type. Therefore, if an error occurred in one of the pots, it would have been found. However, although the lab was fairly reliable because four trials were conducted for each soil type, there were possible sources of error that could have affected the results.
Conclusion:
The results from the lab show that the mixture of the Virginia soil and humus produced the most biomass and the mixture of Virginia soil, sand, and clay produced the least biomass. The original Virginia soil sample produced an amount of biomass between the amounts produced by the other two soil types. The findings from this lab support the hypothesis. The soil that had the highest productivity was the Virginia soil and humus mixture and the soil that was the least productive was the mixture of the Virginia soil, sand, and clay.
Caitlin Rauchle
2-3-10
Testing Soil Productivity
Introduction:
There is a wide variety of soil types depending upon the environment. Some soils have characteristics that make them arable, meaning that they are able to grow crops well. Characteristics that determine a soil’s ability to grow crops include water-holding capacity and capillary action, ion exchange capacity, plant nutrition and soil minerals, pH, and permeability. The soil that was tested in this lab experiment was loam farm soil from Charlottesville, Virginia. Loams are a mixture of sand, clay, and organic material and are slightly to strongly acidic.
The purpose of this lab experiment is to create three soil types (good, bad, and control) from the original Virginia farm soil by adding sand, clay, and/or humus to the soil. The level of productivity of each soil type will be tested by planting alfalfa seeds in each soil and, once the alfalfa seeds have sprouted, finding the biomass produced from the alfalfa seeds produced in each of the soil types. To find which soil (clay, humus, or sand) should be added to the Virginia soil to make it worse or better for growing crops, properties of the Virginia farm soil such as water-holding capacity and capillary action, ion exchange capacity, plant nutrition and soil minerals, pH, and permeability must be tested.
If the Virginia farm soil is tested for its water-holding capacity and capillary action, ion exchange capacity, plant nutrition and soil minerals, pH, and permeability, then it will be determined that to make the Virginia farm soil more arable, humus must be added to the soil because it has good permeability and to make the soil less arable, sand and clay must be added because sand is very impermeable and clay has a low ion exchange capacity. The independent variables for this lab are the types of soils that the alfalfa seeds are planted in (good, bad, or control) and the dependent variable is the biomass of alfalfa produced from each soil type. Variables that must be held constant for all three soil types include the amount of light and water the plants receive and the temperature that the plants are exposed to.
Procedure:
First, we separated half of the original unknown soil sample and set it aside. This half would be the control group soil. We then divided the remaining quantity of soil in half (about one quarter to one half mixing cup for each pile). These two piles would be the testing samples. We then looked over the results of each of the soils regarding their level of permeability, ion exchange, water-holding capacity, etc. Next, we acquired three strips of plastic pots. Each strip contained four pots. In the first strip of four pots, we filled each of the four pots with the original Virginia soil sample.
Based on the results from testing the original sample, we determined that to create a soil that would grow plants better than the original Virginia soil sample, humus would have to be added because it had good permeability, ion exchange capacity, water holding capacity, etc. We filled each of the four pots in the second strip of pots halfway with the Virginia soil sample and the rest of the way with humus. To create a soil that will not grow plants as well as the original Virginia soil sample, we filled each of the four pots in the last strip of pots halfway with the Virginia soil sample and the rest of the way with sand and clay because clay is very impermeable and sand has very low ion exchange capacity. We then marked each strip with they type of soil it contained (good, bad or control). Next, we counted out 30 alfalfa seeds to each pot and gently pressed the seeds under the surface of the soil. We then added 20 mL of water and placed all the pots in an area with ample light. 20 mL of water was added to the soil every day for 6 days. The amount of light and water the pots received and the temperature each pot was exposed to was the kept the same for each pot. After the 6 days, the alfalfa sprouts were taken from the soil and dried, making sure that the alfalfa plants from each soil type were kept separated. Once all of the water had been taken out of the soil, the alfalfa was weighed to find its biomass.
Data Analysis:
The results show that the good soil produced the most biomass, the bad soil produced the least biomass and the control (the original soil sample) had a medium amount of biomass. This suggests that the good soil (the mixture of Virginia soil and humus) was the most productive and the bad soil (the mixture of Virginia soil, sand, and clay) was the least productive of the three types of soils. Although the good soil was the most productive and the bad soil was the least productive, the difference in biomasses between the soil types was very small. The small difference in biomasses between the three soil types could be due to sources of error. Possible sources of error include if not all the soil received exactly the same amount of water, if some seed were not planted correctly and therefore never sprouted, and if some pots contained more soil than others. These errors could alter the results and make some soils produce more alfalfa while other soils produced less alfalfa.
This lab was fairly reliable because four tests were conducted for each soil type. Therefore, if an error occurred in one of the pots, it would have been found. However, although the lab was fairly reliable because four trials were conducted for each soil type, there were possible sources of error that could have affected the results.
Conclusion:
The results from the lab show that the mixture of the Virginia soil and humus produced the most biomass and the mixture of Virginia soil, sand, and clay produced the least biomass. The original Virginia soil sample produced an amount of biomass between the amounts produced by the other two soil types. The findings from this lab support the hypothesis. The soil that had the highest productivity was the Virginia soil and humus mixture and the soil that was the least productive was the mixture of the Virginia soil, sand, and clay.
This lab report meets the requirement for problem solving because in this lab, we had to create our own procedure. We were given the challenge of finding which mixture of different soil types was best for growing alfalfa in. We had to conduct many trials and decide on an effective procedure in order to get accurate results. This report also meets the requirement for organization and analysis of data because we had to gather data about the plants' growth every day throughout the length of the lab. We then had to organize the data meaningfully and use it to come up with our conclusion.
