Get premium membership and access revision papers, questions with answers as well as video lessons.

Got a question or eager to learn? Discover limitless learning on WhatsApp now - Start Now!

Soil 210: Soil Physics Question Paper

Soil 210: Soil Physics

Course:Bachelor Of Science In Agriculture

Institution: Chuka University question papers

Exam Year:2013

CHUKA

UNIVERSITY

UNIVERSITY EXAMINATIONS
EXAMINATIONS FOR THE AWARD OF DEGREE OF
BACHELOR OF SCIENCE AGRICULTURE
SOIL 210: SOIL PHYSICS
STREAMS: BSC AGRIC Y2S1 TIME: 2 HOURS
DAY/DATE: WEDNESDAY 24/4/2013 11.30 AM – 1.30 PM
INSTRUCTIONS:

ANSWER ALL QUESTIONS IN SECTION 1 AND ANY TWO IN SECTION II

SECTION I: (30 MARKS)

1. (a) What is soil consistency? [2 Marks]

(b) State and explain the three adverse effects of suboptimal aeration on plants and soils. [6 Marks]

2. (a) Explain the effect of soil temperature on:

(i) Soil water movement [3 Marks]

(ii) Seed germination [3 Marks]

3. (a) In relation to soil water retention what is hysteresis? [2 Marks]

(b) A sample of moist soil was weighed and placed in an oven and dried at 105? for 24 hrs after which the following data was recorded.

Mass of can + moist soil = 180g
Mass of can + dry soil = 153 g
Mass of empty can = 35g
Calculate the gravimetric water content (w) of the soil. [5 Marks]

4. A 100cm3 undisturbed soil sample has a mass of 165g. After oven drying a 100?, its mass is reduced to 134g. The particle density is 2.6g/cm3. Calculate its;

(i) Bulk density [3 Marks]

(ii) Porosity [3 Marks]

(iii) Volumetric water content. [3 Marks]

SECTION II: 40 MARKS

5. (a) Discuss how climate, soil properties and topography influence soil moisture
content. [15 Marks]

(b) Briefly explain the term osmotic potential. [5 Marks]

6. (a) A sorghum crop was planted on vertisol soil and soil moisture in the profile
measured at the beginning and end of a thirty day period. The following data was recorded.

Soil moisture in the profile on October( 01(Ml) = 300 mm
Precipitation or Rainfall (P) = 70 mm
Irrigation (I) = Nil
Contribution from ground water (C) = Nil
Run-off of 200 cubic m from 2 ha field (R) = 10 mm
Deep drainage (D) = Nil
Soil moisture in the profile on October 31 (M2) = 250 mm
Estimate evapotranspiration (ET) from the field during period 01 to 31 October. [10 Marks]

(b) Given that millet was planted on the adjacent field of sorghum above, and the data
below was recorded;
Soil moisture in the profile on November 10 (Ml) = 150 mm
Precipitation or Rainfall (P) = 600 mm
Irrigation (I) = Nil
Contribution from ground water (C) = Nil
Evapotranspiration (estimated) (ET) = 530 mm
Run-off of 200 cubic m from 1 ha field (RO) = 70 mm
Soil moisture in the profile on February 30 (M2) = 60 mm
Estimate the deep drainage (D) losses form the field during the crop period.
[10 Marks]
7. (a) Discuss the signs of compaction on soil and plant growth. [15 Marks]

(b) Briefly discuss means by which water is held in the soil. [5 Marks]
-------------------------------------------------------------------------------------------------------------

Soil 210: Soil Physics Question Paper

More Question Papers

Popular Exams