Homework Assignment 4
CSS 560
Name:
Points:
Preparation:
Find a location (e.g., on the McCall Field Campus, in Ponderosa State Park) that has a closed (hereafter referred to as “closed canopy site”) and open canopy (hereafter referred to as “open canopy site”) within less than 10 meters of each other (Fig. 1).
Figure 1. Open and closed canopy site.
Take a digital photograph of your sampling site. Next, take 10 soil moisture measurements with the Vernier soil moisture probe in both the closed and open canopy and record your numbers in the table below
Sample / Water content-Open Canopy Site- / Water content
-Closed Canopy Site-
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2
3
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5
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10
Task 1:
Please insert a digital photograph of your sampling site in the space provided below.
Your picture
Task 2:
Do you think there is a statistically significant difference between the soil water content of the open and closed canopy site?
Due to less direct sunlight at the closed canopy site, less energy is available for evapotranspiration at the closed canopy site when compared to the open canopy site. Consequently, I would hypothesize that there is a statistically significant difference between the soil water content of the open and closed canopy site.
Task 3:
Test your hypothesis by using your data and appropriate statistics. Also, please provide the R commander output.
You would use an independent sample (two-sample) t-test to answer this question. Your results might look different – for example, some might find a statistical significant difference whereas others might find that there was not a statistical significant difference between the open and closed canopy site. Always keep in mind that most statistical results will not give a definite answer and might only be site specific.
Task 4:
Let’s say you established a sample plot at the following location:
Lat: 44.9725
Long: -116.05
Please provide a short summary of the soil properties at your sampling location (Hint: You do not have to go to the location – you should be able to answer the question by simply using your computer with internet access).
To give a short summary of the soil properties, you can use the Web Soil Survey ( Once you are on the website, click on the “Start WSS” button in the upper right hand corner. Under the Area of Interest/Quick navigation tab, click on “Latitude and Longitude” and type in the coordinates.
Next, use the area of interest (AOI) tool and draw an area of interest around your plot location.
Finally, click on the Soil Map tab and a soil map appears. It looks like the plot is located within the Map Unit Symbol 33. The Map Unit Name associated with this mapping symbol isMcCall-Rock outcrop complex. To get more information about the soil at your sampling location, simply click on the Map Unit Name.
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