 |
SSA520S - SOIL SCIENCE - 2ND OPP - JAN 2020 |
|
|
1 Page 1 |
▲back to top |
NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF NATURAL RESOURCES AND SPATIAL SCIENCES
DEPARTMENT OF AGRICULTURE AND NATURAL RESOURCES SCIENCES
QUALIFICATION: BACHELOR OF AGRICULTURE
QUALIFICATION CODE: 07BAGR
LEVEL: 5
COURSE CODE: SSA520S
COURSE NAME: SOIL SCIENCE
SESSION:
DURATION:
JANUARY 2020
3 HOURS
PAPER: THEORY
MARKS: 100
SUPPLEMENTARY / SECOND OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S)
Mr Brian J. Mhango
MODERATOR:
Dr Fidelis Mwazi
INSTRUCTIONS
1. Marks for each question are indicated
2. Answer each question on a separate answer sheet
3. Provide your name and student number on the answer booklet(s)
THIS QUESTION PAPER CONSISTS OF 4 PAGES (Excluding this front page)
PERMISSIBLE MATERIALS
1. All written work MUST be done in blue or black ink
2. No books, notes and other additional aids are allowed
3. You are allowed to use a scientific calculator in this examination
|
|
2 Page 2 |
▲back to top |
Soil Science
ANSWER ALL QUESTIONS
QUESTION 1
a) The
is a vertical section through soil mass
A. Soil erosion
B. Soil profile
C. Both Aand B
D. None of the above
b) Wind erosion is common in
A. Humid zones
B. Arid zones
C. Arid and semi-arid zones
D. Arid and Humid zones
c) Wind erosion is more in
A. Cohesive soil
B. Non cohesive soil
C. Rocky soil
D. All of the above
d) The reason for wanting to organize soil knowledge is the basis for:
A. The principle of prioritization
B. The principle of classification
C. The principle of purpose
D. The principle of identity
Supplementary Examination
Page 2 of 5
SSA520S
[100 MARKS]
January 2019
|
|
3 Page 3 |
▲back to top |
Soil Science
SSA520S
e) The mass of dry soil is 380 grams, if the particle desnisty is 38g/cm? then:
A. The soil bulk density is > 39g/cm?
B. The soil bulk density is < 38 g/cm 3
C. The soil bulk density is about 39g/cm?
D. The soil bulk density is unknown
[10]
QUESTION 2
Define and explain sheet and rill erosion.
(10)
QUESTION 3
3.1 Excluding the human factor, name the five factors of soil formation.
(5)
3.2 What is nitrogen fixation and why is it important?
(5)
3.3 According to three principles of soil classification, explain what is meant by “Organization”?
(20)
[30]
QUESTION 4
4.1 Study the table and the hypothetical soil map information below. How many tonnes of sulfur or lime will be
applied to each mapping unit to lower or raise the soil Ph?
(15)
pH
6.0 to 6.5
pH
7.0 to 6.5
Lime Requirements to raise pH in the top 15 cm of the soil (45 kg/m?)
Sand
Loam
Clay
Sandy Loam
1.5
4.2
-
3.2
Sulfur Requirements to Lower pH in the 15 cm of the soil (45 kg/m?)
Sand
Loam
Clay
Sandy Loam
0.25
0.35
0.70
-
Clay Loam
5.5
Clay Loam
-
Supplementary Examination
Page 3 of 5
January 2019
|
|
4 Page 4 |
▲back to top |
Soil Science
SSA520S
Soil Map 1: 27,400
Soil Mapping unit | Topsoil Texture | Soil pH | Area (ha)
A
Sand
7
300
B
Sandy loam
6
1000
C
Clay loam
6
750
D
Clay
7
750
E
loam
6
800
4.2 Draw a diagram showing how rainfall erosivity and soil erodibility factors contribute to soil’s susceptibility
to water erosion
(10)
[25]
QUESTION 5
5.1 The table below is soil profile analysis data. Using the data determine the soil texture of the seven horizons.
(9)
Supplementary Examination
Page 4 of 5
December 2019
|
|
5 Page 5 |
▲back to top |
Soil Science
SSA520S
Horizon
Ap
Bw1
Bw2
Bw3
Bwk1
Bwk2
Bck
Depth (Cm)
0-12
12-35
35-48
48-76
76-96
96-126
126-155
Particle Size Distribution
Sand
Silt
48
16
47
17
45
17
46
18
39
19
39
20
27
24
5.2 Soil plant nutrients can be divied into two groups, that is, nutrients from air and water and nutrients from the
soil, lime and commercial fertilizers. Using the table below list all the nutrients under each column in the table.
(16)
Nutreints from Air & water
PLANTS ESSENTIAL NUTRIENTS
Nutrients from Soil, Lime orand Commercial Fertilizers
Primary Nutrients
Secondary Nutrients
Micronutrients
(16)
[25]
Supplementary Examination
Page 5 of 5
December 2019