Worksheet I – Soil and Water Relationships (Fall 2023) (2)

Worksheet I – Soil and Water Relationships Due Friday, October 27 th at 11:59 PM. NC State Honor Pledge: I, ( P RINT Y OUR NAME ) , have neither given nor received unauthorized aid on this worksheet. It is the product of my work only. I understand any academic misconduct will be handled according to university policy, as set forth in the code of student conduct. ( SIGN YOUR NAME ) (D ATE ) Important things to keep in mind: ● Show all work when doing calculations. Full credit will only be given if work is shown. Calculations can be handwritten or typed and must be legible. ● The discussion portion of this experiment summary must be typed. We will reduce your grade by 10 points if it is not typed. ● All graphs must be made using Excel or a similar software program. We will reduce your grade by 10 points if graphs are not made using Excel or a similar software program. ● Submit your assignment as one PDF on Moodle . File submission is located under the Soil and Water Relationships section in the SSC 201 Moodle course page. You will submit your assignment to the folder with your section number. For example, if you are in section 002, then you will submit your assignment to Worksheet I (Section 002). ● Handwritten calculations need to be turned into a PDF for submission. See Moodle for a list of phone apps that can convert pictures to PDFs and combine PDF files. 1. Experimental Datasheet: (10 pts). Fill out the experimental data sheet below for the soil weight for each treatment and the bulk density for the two soils. Show all work below. Full credit will not be given unless all work is shown. If you need more room, then attach a separate page to this summary worksheet . Experiment Datasheet Weight of empty cup + towel [g] 2.6 g Sandy soil Clayey soil Page - 1

Volume of water in cup (i.e., volume of soil) 33.0 cm 3 50.5 cm 3 Bulk density ______________ g/ cm 3 ______________ g/ cm 3 Sample weights (g) Sandy soil Clayey soil Treatment Code Moisture class Cup + soil (g) Soil (g) Cup + soil (g) Soil (g) Never Drained S Saturated 72.3 85.1 Drained 1 day FC Field capacity 59.7 73.4 Drained 6 days WP Wilting point 53.2 55.5 Never Wet AD Air Dry 52.5 52.3 Dried in oven OD Oven dry ---------- 49.7 ---------- 48.8 2. Water Content: (20 pts). Using the composited data provided by the lab instructors, calculate moisture content on a weight basis. Then use the bulk density to calculate volumetric moisture content and record all data in the following table. Show all work below . Full credit will not be given unless all work is shown. If you need more room, then attach a s eparate page to this summary worksheet . Sandy soil Clayey soil Treatment Code Weight basis (g/g) Volume basis (cm 3 /cm 3 ) Weight basis (g/g) Volume basis (cm 3 /cm 3 ) Saturated S Field capacity FC Wilting point WP Air Dry AD Page - 2

b. Macropores volume: Sandy soil: ________ cm 3 Clayey soil: ________ cm 3 c. Mesopores volume: Sandy soil: ________ cm 3 Clayey soil: ________ cm 3 d. Micropores volume: Sandy soil: ________ cm 3 Clayey soil: ________ cm 3 e. Total pore volume: Sandy soil: ________ cm 3 Clayey soil: ________ cm 3 f. What percent are macropores, mesopores, and micropores compared to the total pore volume for each soil? Complete the table below. HINT: Macropores + mesopores + micropores = 100% Sandy Soil Clayey Soil Page - 4

Macropores (%) Mesopores (%) Micropores (%) 5. Water Depth Calculations : (6 pts). Show all work below. Full credit will not be given unless all work is shown. If you need more room, then attach a separate page to this summary worksheet . a. How many centimeters of plant available water could be held in a 25-cm layer of the sandy soil? b. How many centimeters of irrigation must be applied to the clayey soil to fill the top 25-cm to field capacity if the soil is currently at permanent wilting point? All questions in the results section must be typed and double spaced. All graphs must be made in Excel or using a similar software program. Responses should be well organized with a neat, professional appearance. Grammar and spelling MUST BE correct. If you use a resource, be certain to properly cite the resource. You can use the citation builder available on the D.H. Hill Library’s website: http://www.lib.ncsu.edu/citationbuilder/ 6. Results : a. Fill out the table below with your answer from problem #4b-d. Use this table to make a column graph of the different pore sizes in the two soils. Click here for an example column graph . (5 pts). i. Label x-axis pore size ii. Label y-axis pore space (cm 3 ) iii. Chart title should be pore size distribution iv. Include a figure legend to differentiate between the two soils Page - 5

d. What soil has more plant-available water and why? Use numbers calculated and reference the graph(s) made. Points will be deducted if data and the graph(s) are not referenced in text. The answer must be at least 3 sentences. (5 pts.) e. You have two fields, one with a sandy soil and one with a clayey soil. You will be growing sweet potatoes in these fields and will need to irrigate both fields. Which field will you need to irrigate most often and why? The answer must be at least 3 sentences. (5 pts). f. You have sloping fields with sandy soil and clayey soil. During a heavy rainfall, which sloping field is most likely to produce more runoff and why? Runoff is water that cannot enter the soil because all of its pores are filled with water. The answer must be at least 3 sentences. (5 pts). Page - 7