Question 1

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

Accepted Answer

A) True 
 B)False  False

Question 2

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 D

Question 3

Saline soils are characterized by _______.

Accepted Answer

A) high CaCO3 levels near the soil surface 
B) sodium adsorption ratios of 13 or higher 
C) electrical conductivity of standard saturated paste of less than 4 dS/m 
D) pH values of less than 8.5 
E) low chloride and sulfate contents 
A) high CaCO3 levels near the soil surface 
B) sodium adsorption ratios of 13 or higher 
C) electrical conductivity of standard saturated paste of less than 4 dS/m 
D) pH values of less than 8.5 
E) low chloride and sulfate contents D

Question 4

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 5

Normal alkaline soils are characterized by all but which one of the following?

Accepted Answer

A) low levels of available iron 
B) high levels of molybdenum 
C) high levels of exchangeable sodium 
D) low levels of available manganese 
E) low levels of available boron 
A) low levels of available iron 
B) high levels of molybdenum 
C) high levels of exchangeable sodium 
D) low levels of available manganese 
E) low levels of available boron

Question 6

Irrigation of a saline-sodic soil with water very low in salts could lead to the formation of a sodic soil.

Accepted Answer

A) True 
 B)False

Question 7

Sodic soils generally have a poor physical condition.To what is this most likely due?

Accepted Answer

A) low organic matter content 
B) impact of raindrops on the soil surface 
C) dispersal of the Na saturated soil colloids 
D) precipitation of the Ca2+ and Mg2+ ions as carbonates 
E) high content of smectite in the soils 
A) low organic matter content 
B) impact of raindrops on the soil surface 
C) dispersal of the Na saturated soil colloids 
D) precipitation of the Ca2+ and Mg2+ ions as carbonates 
E) high content of smectite in the soils

Question 8

Phosphate availability is constrained in alkaline soils by the presence of iron and aluminum oxides.

Accepted Answer

A) True 
 B)False

Question 9

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 10

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 11

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

Accepted Answer

A) True 
 B)False

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

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 14

A farmer started irrigating a soil some 10 years ago but in recent years yields have declined and the soil physical condition has deteriorated.Which of the following most likely accounts for this situation?

Accepted Answer

A) high content of Ca and Mg in the irrigation water 
B) failure to use conservation tillage to reduce salt accumulation at the soil surface 
C) high SAR of the irrigation water 
D) excessive drainage of the soil 
E) high gypsum content in the soil 
A) high content of Ca and Mg in the irrigation water 
B) failure to use conservation tillage to reduce salt accumulation at the soil surface 
C) high SAR of the irrigation water 
D) excessive drainage of the soil 
E) high gypsum content in the soil

Question 15

If you want to reclaim a saline soil,which of the following practices would you most likely use?

Accepted Answer

A) Add CaCO3 to reduce the exchangeable Na+ level. 
B) Leach the soil with low salt containing water. 
C) Leach the soil with water having a high SAR ratio. 
D) Leach the soil with water high in Ca2+ and Mg2+. 
E) Leach the soil with water high in bicarbonates. 
A) Add CaCO3 to reduce the exchangeable Na+ level. 
B) Leach the soil with low salt containing water. 
C) Leach the soil with water having a high SAR ratio. 
D) Leach the soil with water high in Ca2+ and Mg2+. 
E) Leach the soil with water high in bicarbonates.

Question 16

Attempts to leach the excess salts from a saline-sodic soil resulted in a marked reduction of crop yields.To what is this most likely due?

Accepted Answer

A) deficiency of iron and manganese 
B) increase in percentage sodium saturation 
C) removal of Ca2+ and Mg2+ ions from the exchange complex 
D) increase in the soil pH 
E) increase in the Al3+ concentration 
A) deficiency of iron and manganese 
B) increase in percentage sodium saturation 
C) removal of Ca2+ and Mg2+ ions from the exchange complex 
D) increase in the soil pH 
E) increase in the Al3+ concentration

Question 17

Gypsum is the most widely used chemical for the reclamation of sodic soils.What characteristic likely accounts for this popularity?

Accepted Answer

A) Gypsum is abundant and low priced. 
B) Gypsum is quite insoluble so it remains in the soil for long periods of time. 
C) Gypsum provides sulfates that attract Na+ from the exchange complex. 
D) Gypsum forms sulfuric acid that helps reduce the soil pH. 
E) Gypsum reacts with Na+ ions to form insoluble Na2SO4. 
A) Gypsum is abundant and low priced. 
B) Gypsum is quite insoluble so it remains in the soil for long periods of time. 
C) Gypsum provides sulfates that attract Na+ from the exchange complex. 
D) Gypsum forms sulfuric acid that helps reduce the soil pH. 
E) Gypsum reacts with Na+ ions to form insoluble Na2SO4.

Question 18

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 19

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 20

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

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

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

Saline soils are characterized by _______.

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

Normal alkaline soils are characterized by all but which one of the following?

Irrigation of a saline-sodic soil with water very low in salts could lead to the formation of a sodic soil.

Sodic soils generally have a poor physical condition.To what is this most likely due?

Phosphate availability is constrained in alkaline soils by the presence of iron and aluminum oxides.

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

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

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

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

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

A farmer started irrigating a soil some 10 years ago but in recent years yields have declined and the soil physical condition has deteriorated.Which of the following most likely accounts for this situation?

If you want to reclaim a saline soil,which of the following practices would you most likely use?

Attempts to leach the excess salts from a saline-sodic soil resulted in a marked reduction of crop yields.To what is this most likely due?

Gypsum is the most widely used chemical for the reclamation of sodic soils.What characteristic likely accounts for this popularity?

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

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

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

The Colloidal Fraction: 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

Calcium,magnesium and Trace Elements

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Geographic Information About Soils

Prospects for Global Soil Quality As Affected by Human Activities

Filters

Exam 10: Soils of Dry Regionsalkalinity,salinity and Sodicity

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

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

Saline soils are characterized by _______.

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

Normal alkaline soils are characterized by all but which one of the following?

Irrigation of a saline-sodic soil with water very low in salts could lead to the formation of a sodic soil.

Sodic soils generally have a poor physical condition.To what is this most likely due?

Phosphate availability is constrained in alkaline soils by the presence of iron and aluminum oxides.

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

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

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

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

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

A farmer started irrigating a soil some 10 years ago but in recent years yields have declined and the soil physical condition has deteriorated.Which of the following most likely accounts for this situation?

If you want to reclaim a saline soil,which of the following practices would you most likely use?

Attempts to leach the excess salts from a saline-sodic soil resulted in a marked reduction of crop yields.To what is this most likely due?

Gypsum is the most widely used chemical for the reclamation of sodic soils.What characteristic likely accounts for this popularity?

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

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

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

The Colloidal Fraction: 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

Calcium,magnesium and Trace Elements

Practical Nutrient Management

Soil Erosion and Its Control

Soils and Chemical Pollution

Geographic Information About Soils

Prospects for Global Soil Quality As Affected by Human Activities

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?