Page 40 - soil-plant-water relationship and water requirement

SOIL-PLANT-WATER RELATIONSHIP AND WATER REQUIREMENT

EXERCISE 3

1. Based on the information on given below, calculate :

i. the depth of water needed to raise the moisture to the field capacity level
ii. the maximum available moisture of the soil
DATA;

Root zone depth = 0.8 m
Permanent wilting point = 10cm per 100cm soil

Field capacity = 25cm per 100cm soil
Relative moisture = 15cm per 100 cm soil

2. A vegetable farm is developed with micro-irrigation system. If the depth of root zone
is 45 cm, the moisture at field capacity is 20 %, wilting point remain at 10 % and ET 6
mm/day. Calculate available water content (AWC), Moisture at the root zone and
Irrigation depth by assume that the irrigation start when available moisture lose 60 %.

3. Sketch and label the diagram of Soil Water Parameters and Water Classes or
classification.

4. Soil sample at Politeknik Kota Bharu the soil moisture water content and data below
are obtained:

Can weight 22 g

Can weight + Soil sampel 53 g

Can weight + Soil sample after 12 hours dried oven 42 g

i. State the method used above to determine soil moisture content.

ii. Calculate percentages of soil moisture content based on weight.

5. An irrigation system is designed for a farm on loam land. Based on the information
and graph below, calculate:

a. the amount of moisture in the root zone
b. depth of application for each irrigation
Depth of corn root zone: 1.2 m

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