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SSA520S - SOIL SCIENCE - 1ST OPP - NOV 2022 |
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r
nAmlBIA unlVERSITY
OF SCIEn CE Ano TECHn OLOGY
FACULTYOf HEALTH,NATURAL RESOURCESAND APPLIEDSCIENCES
DEPARTMENT OF AGRICULTUREAND NATURAL RESOURCESSCIENCES
QUALIFICATION: BACHELOROF SCIENCEIN AGRICULTURE& BACHELOROF HORTICULTURE
QUALIFICATION CODE
07BAGA, 07BHOR
COURSECODE: SSA520S
COURSENAME: Soil Science
NQF LEVEL:5
SESSION:
DURATION: 3 Hours
NQF CREDITS: 12
November 2022
MARKS: 100
fiRST OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S) Mr Brian J. Mhango
MODERATOR: Dr T. Nzuma
NSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
PERMISSIBLE MATERIALS
1. Examination question paper
2. Answering book
3. Scientific calculator
THIS QUESTION PAPERCONSISTSOF 4 PAGES(Excluding this front page)
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QUESTION 1
ANSWER ALLTHE QUESTIONS
a) In the table below provide the% particle sizes and all applicable soil texture names.
I
%sand
70
% clay
10
50
10
25
b) With to soil colours, answer the following questions:
% silt
60
Soil texture name
(20)
i. What is meant by transitional soil colour hues?
ii. Name any two transitional soil colours.
iii. How many soil colour hues are in each category of soil hues?
iv. How many soil colours are associated with a single soil colour hue, for example 7.SYR?
v. Explain the soil colour symbol 2.5YR 3/20.
(10)
[30]
QUESTION 2
Define the following soi! science abbreviations or terms:
a) Sand
b} Textural triangle
c} Bulk density
d) Soil horizon
e} NPK
f) Molybdenum
g) SAR
h} Epipedon
i) ph dependent charge
j} USLEor RUSLE
(2)
(2)
(2)
(2)
(2)
(2}
(2)
(2}
(2)
(2)
[20)
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("
QUESTION 3
Study the table and the soil map information below.
pH
6.0 to 6.5
pH
7.0 to 6.5
'I
lime Requirements to raise pH in the top 15 cm of the soil (45 kg/m 2)
Sand
Loam
Clay Sandy Loam Clay Loam
1.5
4.2
-
3.2
5.5
Sulfor Requirements to Lower pH in the 15 cm of the soil (45 kg/m 2)
Sand
Loam
Clay Sandy Loam Clay Loam
0.25
0.35
0.70
-
-
Soil Map 1: 27,400
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Soil Mapping unit
A
B
C
D
E
· Topsoil Texture
Sand
Sandy loam
Clay loam
Clay
loam
Soil pH
7
6
6
7
6
Area (ha}
300
1000
750
750
800
a) How many tonnes of sulfur or lime will be applied to each mapping unit to lower or raise the soil
pH?
(20)
b) It is reported that all the 5 soil mapping units require units of nitrogen for fertilization (A=25 units,
B=15 units, C=20 units, 0=18 units and E=33 units). The brand offertilizer available in the country
is labelled 15:10:8:5. Calculate the application rates in kg/ha of this fertilizer for each soil mapping
unit.
(15)
c) If the fertilizer brand in (b) above costs N$2,000 per 50kg bag, what will be the cost of each
application rate per soil mapping unit?
(15)
[SO]
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SOIL TEXTURE TRIANGLE
7
6
THEEND
Total Marks: 100
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