The most important soil micro-organisms concerned with decay and nutrients-recycling are

A. bacteria and fungi

B. fungi and algea

C. alga and actinomyces

D. actinomyces and bacteria

E. bacteria and algea

The nutrient content of soil may be influenced by the following except

A. harrowing

B. topography

C. cropping

D. fallowing

E. grazing

What happens to the nitrogen and sulphur contents of vegetation when burning is used as a means of lans clearing? They

A. are released by burning and lost as gases

B. remain in ash as nitrates and sulphates

C. raise the PH of an acid soil

D. are released into the soil thus increasing the nutrients of the soil

E. activate the soil microbes afetr burning

Which of the following does not occur as a result of poor drained soil?

A. mottling near the top

B. decrease in rooting depth

C. change in colour of the subsoil

D. decrease in organic matter content

E. increase in oxygen level of the soil

The different types of soil are determined by the relative amounts of each of the following components except

A. rocks

B. air

C. water

D. minerals

E. organic matter

Fertilizers that usually contain one nutrient which can be used directly by plants are commonly called

A. organic fertilizers

B. mixed fertilizers

C. inorganic fertilizers

D. compound fertilizers

E. straight fertilizers

A soil with particles of less than 0.002mm in diameter is referred to as

A. clay

B. silt

C. sand

D. gravel

E. humus

Which of the following factors does not bring about soil formation?

A. climate

B. time

C. parent material

D. sunshine

E. topography

Plant micro-nutrients include the following except

A. sulphur

B. copper

C. iron

D. zinc

E. chlorine

Most crop plants do not survive in water-logged soils because

A. the dissolved nutrients are too diluted for crop plants

B. the plants will not photosynthesize

C. their leaves are turgid for respiration

D. their physiological processes will be increased

E. oxygen has been displaced to its deficiency for crops