Soil Science Final

A greenhouse operator was growing ornamental woody plants in 15-cm-tall plastic containers filled with a loamy sand. He waters the containers daily with a sprinkler system. His first batch of 1000 plants yellowed and died from too much water and not enough air. As an employee of the greenhouse, you suggest that he use 30-cm-tall pots for the next batch of plants. Explain
your reasoning.

Give four reasons why compacting a soil is likely to reduce the amount of water available to growing plants.

Since even rapidly growing, finely branched root systems rarely contact more than 1 or 2% of the soil particle surfaces, how is it that the roots can utilize much more than 1 or 2% of the water held on these surfaces?

Draw a simple diagram of the hydrologic cycle using a separate arrow to represent these processes: evaporation, transpiration, infiltration, interception, percolation, surface runoff, and soil storage.

Describe and give an example of the indirect effects of plants on the hydrologic balance through their effects on the soil

Weed control should reduce water losses by what process?

Comment on the relative advantages and disadvantages of organic versus plastic mulches.

What does conservation tillage conserve? How does it do it?

What soil features may limit the use of a site for a septic tank drain field?

What is aerenchyma tissue, and how does it affect plant-soil relationships?

What are the three main components that define a wetland?

Hydrogen bonding

H atom of one water molecule is attracted to O on neighboring water molecule; low energy bond

Capillary action

Action by which the surface of a liquid is elevated or depressed when in contact with a solid depending on the relative attraction of the molecules of the liquid for each other and for those of the solid

Soil water potential

Saturated flow

Takes place when the soil pores are completely filled with water 

Preferential flow

non uniform movement of water and its solutes through a soil along certain pathways which are often macropores

Unsaturated flow

Occurs when the larger pores in the soil are filled with air, leaving only the smaller pores to hold and transmit water 

Infiltration

The process by which water enters the soils pore space and becomes soil water 

Percolation

the downward movement of water within the soil profile; involved both saturation and unsaturated flow

Stratified

different textures encountered in profile as water moves downward, it is slowed when it reaches a different layer (does not matter is finer or coarser), more water is held above the layer 

Gravitational water

Flows downward due to gravity until soil hold water against this force, causes most leaching

Field capacity

The percent of water remaining in a soil

Permanent wilting percentage

Permanent wilting point

moisture content of the soil at which plants wilt and fail to recover their trugidity when placed in dark humid atmosphere

Available water

Water retained in soils between field capacity and wilting coefficient

Hygroscopic coefficient

amount of moisture in dry soil when it is in equilibrium with some standard RH near a saturated atmosphere (about 98%), expressed in terms of percentages on the basis of oven-dry soil

Hydrologic cycle

Watershed

Evaporation

Transpiration

Interception

Surface runoff

Drainage

Capillary water

Soil storage water

Evapotranspiration

Evapotranspiration efficiency

Mulch

Vegetative mulch

Plastic mulch

Stubble mulching

No-till

Percolation or drainage water

Runoff water

Water table

Groundwater

Vadose zone

Eutrophication

Saturated soils

Septic tank

Drain field

Mound drain field system

Hydrophyte

Aerenchyma

Wetlands

Hydroperiod

Residence time

Hydric soil

Aquifers

The following are characteristics of a water molecule.

It has a positive and a negative side.

Capillarity in soils _____.

involves both adhesion and cohesion

In which of the following situations would you expect downward movement of soil water through the profile to be most rapid?

uniformly textured sandy loam profile

In which of the following "forms" of soil water are pesticides, excess plant nutrients and waste

gravitational

Plant roots obtain access to soil water in which of the following ways?

Roots extend into most soil area & Water flows to the roots by capillary (B&D)

Which of the following will increase the evaporation (E) from the soil surface?

none of the above

Urban development of land under natural vegetation or agriculture usually greatly _____ soil infiltration capacity and therefore greatly increases _______

decreases …… stream bank erosion.

The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by _____.

the presence of macropores in the soil

If you dug a deep hole in your back yard and water started to seep into the hole it would fill the hole up to ________.

the water table

The most common form of on-site waste water treatment for homes not hooked up to sewer lines is the _______.

septic tank and drain field

Which of the following processes are most apt to encourage good soil aeration?

creation of more macropores

Which of the following is (are) considered necessary features for an area to be delineated as a wetland?

hydric soils

Why is soil quality likely of greater social concern today than it was 100 years ago?

What is meant by soil resistance and soil resilience as they relate to soil quality?

What are the positive and negative effects on soil quality of the intensive agricultural practices of the past half century?

What is shifting cultivation; why is its use today in many areas resulting in a decline in soil quality; and what are some promising alternatives?

What are the 5 principle of soil health? How does each help improve overall soil health?

Soil health

Soil resistance

Soil resilience

Shifting cultivation

Marginal land

Organic farming

Agroforestry

Alley cropping

Which type of flow of liquid water in the soil occurs when the soil pores are completely filled with water?

Saturated flow

In which of the following situations would you expect the downward movement of soil water through the profile to be the most rapid?

Uniformly textured sandy loam profile