Question 1

Saline-sodic soils are characterized by all but which one of the following?

Accepted Answer

A) soil pH less than 8.5 
B) exchangeable sodium percentage greater than 15 
C) EC 4 dS/m or higher 
D) sodium adsorption ratio greater than 13 
E) CaCO3 layer near the soil surface. 
A) soil pH less than 8.5 
B) exchangeable sodium percentage greater than 15 
C) EC 4 dS/m or higher 
D) sodium adsorption ratio greater than 13 
E) CaCO3 layer near the soil surface.

Question 2

Which of the following comparisons of the three different classes of salt-affected soils is correct?

Accepted Answer

A) Sodic soils generally have the lowest pH. 
B) Saline soils are generally higher in soluble salts than saline-sodic soils. 
C) Sodic soils generally have the highest EC levels. 
D) The pH of saline soils is generally above 8.5. 
E) Sodic soils are commonly formed by leaching saline-sodic soils. 
A) Sodic soils generally have the lowest pH. 
B) Saline soils are generally higher in soluble salts than saline-sodic soils. 
C) Sodic soils generally have the highest EC levels. 
D) The pH of saline soils is generally above 8.5. 
E) Sodic soils are commonly formed by leaching saline-sodic soils.

Question 3

Which of the following plants would be most apt to tolerate high soil salinity?

Accepted Answer

A) cotton 
B) alfalfa 
C) apples 
D) corn 
E) tomato 
A) cotton 
B) alfalfa 
C) apples 
D) corn 
E) tomato

Question 4

The cation exchange capacities of alkaline soils are commonly lower than those of comparable soils in humid regions.

Accepted Answer

A) True 
 B)False

Question 5

Saline soils are characteristic of arid and semiarid areas with poor internal drainage.

Accepted Answer

A) True 
 B)False

Question 6

The cation exchange capacities of alkaline soils are generally higher than those of acid soils (Vertisols excepted).Which of the following characteristics of alkaline soils most likely accounts for this high CEC?

Accepted Answer

A) high humus content 
B) high content of hydrous oxides of iron and aluminum 
C) high exchangeable calcium 
D) high exchangeable sodium content 
E) high content of 2:1 type clays 
A) high humus content 
B) high content of hydrous oxides of iron and aluminum 
C) high exchangeable calcium 
D) high exchangeable sodium content 
E) high content of 2:1 type clays

Question 7

Sodic soils generally have better physical conditions than either saline or saline-sodic soils.

Accepted Answer

A) True 
 B)False

Question 8

Lack of adequate drainage in irrigation projects leads to the accumulation of CaCO3 that is responsible for the high pH values above 8.5.

Accepted Answer

A) True 
 B)False

Question 9

Sulfuric acid is sometimes added to irrigation water to help in the reclamation of sodic soils.

Accepted Answer

A) True 
 B)False

Question 10

Removal of excess salts from the soil profile is a requisite for the reclamation of a saline soil.

Accepted Answer

A) True 
 B)False

Question 11

If you wanted to reduce the percentage sodium saturation from 30% to 5% in a sodic soil with a CEC of 20 cmolc/kg, how many cmolc's of CaSO4 would need to react with 1 kg of this soil?

Accepted Answer

A) 30 
B) 20 
C) 10 
D) 5 
E) 2 
A) 30 
B) 20 
C) 10 
D) 5 
E) 2

Question 12

The growth of plants on sodic soils is constrained by all but one of the following:

Accepted Answer

A) caustic influence of high pH caused by sodium carbonate and bicarbonate 
B) toxicity of bicarbonate and other anions 
C) low micronutrient availability due to high pH 
D) oxygen deficiency due to breakdown of soil structure or 
E) toxicity of very high levels of calcium carbonate 
A) caustic influence of high pH caused by sodium carbonate and bicarbonate 
B) toxicity of bicarbonate and other anions 
C) low micronutrient availability due to high pH 
D) oxygen deficiency due to breakdown of soil structure or 
E) toxicity of very high levels of calcium carbonate

Question 13

Gypsum plus irrigation reduces the pH of sodic soils by replacing sodium from the exchange complex and removing it from the soil.

Accepted Answer

A) True 
 B)False

Question 14

In desert areas, the soil under scattered clumps of natural vegetation is usually depleted of nutrients compared to the unvegetated soil between clumps.

Accepted Answer

A) True 
 B)False

Question 15

The presence of neutral salts in salt-affected soils helps keep the pH from rising above 8.5.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following characteristics of irrigation water is most apt to stimulate the formation of a sodic soil?

Accepted Answer

A) high selenium content 
B) high Ca2+ and Mg2+ content 
C) high content of chlorides 
D) low pH 
E) high SAR values 
A) high selenium content 
B) high Ca2+ and Mg2+ content 
C) high content of chlorides 
D) low pH 
E) high SAR values

Question 17

The high pH of sodic soils is due to the high saturation of the colloidal complex with calcium.

Accepted Answer

A) True 
 B)False

Question 18

A homeowner in New Mexico attempted to grow azaleas in a well drained soil (pH 7.5) but the plants were stunted and the leaves were yellow.What is the most likely cause of this constraint?

Accepted Answer

A) P deficiency 
B) Mn toxicity 
C) Fe deficiency 
D) Ca toxicity 
E) Na toxicity 
A) P deficiency 
B) Mn toxicity 
C) Fe deficiency 
D) Ca toxicity 
E) Na toxicity

Question 19

The degradation of irrigated soils across the once very productive "Fertile Crescent" of the Middle East was due primarily to _____.

Accepted Answer

A) high calcium and magnesium levels in the irrigation waters 
B) high levels of calcium-containing salt in the irrigation water 
C) inadequate equipment and power to properly cultivate the soil 
D) poor internal drainage of the soils 
E) destructive wars in the region 
A) high calcium and magnesium levels in the irrigation waters 
B) high levels of calcium-containing salt in the irrigation water 
C) inadequate equipment and power to properly cultivate the soil 
D) poor internal drainage of the soils 
E) destructive wars in the region

Question 20

Normal alkaline soils often exhibit deficiencies of available iron and manganese.

Accepted Answer

A) True 
 B)False

Saline-sodic soils are characterized by all but which one of the following?

Which of the following comparisons of the three different classes of salt-affected soils is correct?

Which of the following plants would be most apt to tolerate high soil salinity?

The cation exchange capacities of alkaline soils are commonly lower than those of comparable soils in humid regions.

Saline soils are characteristic of arid and semiarid areas with poor internal drainage.

The cation exchange capacities of alkaline soils are generally higher than those of acid soils (Vertisols excepted).Which of the following characteristics of alkaline soils most likely accounts for this high CEC?

Sodic soils generally have better physical conditions than either saline or saline-sodic soils.

Lack of adequate drainage in irrigation projects leads to the accumulation of CaCO₃ that is responsible for the high pH values above 8.5.

Sulfuric acid is sometimes added to irrigation water to help in the reclamation of sodic soils.

Removal of excess salts from the soil profile is a requisite for the reclamation of a saline soil.

If you wanted to reduce the percentage sodium saturation from 30% to 5% in a sodic soil with a CEC of 20 cmol_c/kg, how many cmol_c's of CaSO₄ would need to react with 1 kg of this soil?

The growth of plants on sodic soils is constrained by all but one of the following:

Gypsum plus irrigation reduces the pH of sodic soils by replacing sodium from the exchange complex and removing it from the soil.

In desert areas, the soil under scattered clumps of natural vegetation is usually depleted of nutrients compared to the unvegetated soil between clumps.

The presence of neutral salts in salt-affected soils helps keep the pH from rising above 8.5.

Which of the following characteristics of irrigation water is most apt to stimulate the formation of a sodic soil?

The high pH of sodic soils is due to the high saturation of the colloidal complex with calcium.

A homeowner in New Mexico attempted to grow azaleas in a well drained soil (pH 7.5) but the plants were stunted and the leaves were yellow.What is the most likely cause of this constraint?

The degradation of irrigated soils across the once very productive "Fertile Crescent" of the Middle East was due primarily to _____.

Normal alkaline soils often exhibit deficiencies of available iron and manganese.

The Soils Around US

Formation of Soils From Parent Materials

Soil Classification

Soil Architecture and Physical Properties

Soil Water: Characteristics and Behavior

Soil and the Hydrologic Cycle

Soil Aeration and Temperature

Soil Colloids: Seat of Soil Chemical and Physical Activity

Soil Acidity

Organisms and Ecology of the Soil

Soil Organic Matter

Nitrogen and Sulfur Economy of Soils

Soil Phosphorus and Potassium

Micronutrients and Other Trace Elements

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Geographic Soils Information

Prospects for Global Soil Quality

Filters

Exam 10: Soils of Dry Regions: Alkalinity, Salinity, and Sodicity

Saline-sodic soils are characterized by all but which one of the following?

Which of the following comparisons of the three different classes of salt-affected soils is correct?

Which of the following plants would be most apt to tolerate high soil salinity?

The cation exchange capacities of alkaline soils are commonly lower than those of comparable soils in humid regions.

Saline soils are characteristic of arid and semiarid areas with poor internal drainage.

The cation exchange capacities of alkaline soils are generally higher than those of acid soils (Vertisols excepted).Which of the following characteristics of alkaline soils most likely accounts for this high CEC?

Sodic soils generally have better physical conditions than either saline or saline-sodic soils.

Lack of adequate drainage in irrigation projects leads to the accumulation of CaCO3 that is responsible for the high pH values above 8.5.

Sulfuric acid is sometimes added to irrigation water to help in the reclamation of sodic soils.

Removal of excess salts from the soil profile is a requisite for the reclamation of a saline soil.

If you wanted to reduce the percentage sodium saturation from 30% to 5% in a sodic soil with a CEC of 20 cmolc/kg, how many cmolc's of CaSO4 would need to react with 1 kg of this soil?

The growth of plants on sodic soils is constrained by all but one of the following:

Gypsum plus irrigation reduces the pH of sodic soils by replacing sodium from the exchange complex and removing it from the soil.

In desert areas, the soil under scattered clumps of natural vegetation is usually depleted of nutrients compared to the unvegetated soil between clumps.

The presence of neutral salts in salt-affected soils helps keep the pH from rising above 8.5.

Which of the following characteristics of irrigation water is most apt to stimulate the formation of a sodic soil?

The high pH of sodic soils is due to the high saturation of the colloidal complex with calcium.

A homeowner in New Mexico attempted to grow azaleas in a well drained soil (pH 7.5) but the plants were stunted and the leaves were yellow.What is the most likely cause of this constraint?

The degradation of irrigated soils across the once very productive "Fertile Crescent" of the Middle East was due primarily to _____.

Normal alkaline soils often exhibit deficiencies of available iron and manganese.

The Soils Around US

Formation of Soils From Parent Materials

Soil Classification

Soil Architecture and Physical Properties

Soil Water: Characteristics and Behavior

Soil and the Hydrologic Cycle

Soil Aeration and Temperature

Soil Colloids: Seat of Soil Chemical and Physical Activity

Soil Acidity

Organisms and Ecology of the Soil

Soil Organic Matter

Nitrogen and Sulfur Economy of Soils

Soil Phosphorus and Potassium

Micronutrients and Other Trace Elements

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Geographic Soils Information

Prospects for Global Soil Quality

Filters

Lack of adequate drainage in irrigation projects leads to the accumulation of CaCO₃ that is responsible for the high pH values above 8.5.

If you wanted to reduce the percentage sodium saturation from 30% to 5% in a sodic soil with a CEC of 20 cmol_c/kg, how many cmol_c's of CaSO₄ would need to react with 1 kg of this soil?