Soil and Water Erosion Overview

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Questions and Answers

Which type of erosion involves the removal of soil by the impact of raindrops?

Rill Erosion

Gully Erosion

Tunnel Erosion

Splash Erosion (correct)

Which factor does NOT influence soil erodibility?

Soil Color (correct)

Surface Sealing

Soil Structure

Soil Texture

What is the primary agent in water erosion processes?

Water (correct)

Wind

Gravity

Ice

Which of the following is a type of gully erosion?

Streambank Erosion Signup and view all the answers

What does runoff erosivity primarily depend on?

Rainfall and Runoff Characteristics Signup and view all the answers

Which erosion type results in larger channels that can carry significant water flow?

Gully Erosion Signup and view all the answers

Which statement accurately describes rainfall erosivity?

It is a measure of the potential impact of rainfall on erosion. Signup and view all the answers

Which erosion process is likely to occur on steep slopes with high rainfall intensity?

Gully Erosion Signup and view all the answers

What is the impact of straight rows combined with residue cover on the quality of small grains?

Demonstrates both poor and good quality depending on conditions Signup and view all the answers

Which combination of cultivation methods provides the best quality for legumes when contoured and terraced?

Legume rotations combined with contoured and terraced methods Signup and view all the answers

What percentage cover is associated with non-cultivated lands like pasturelands and grasslands?

75% cover Signup and view all the answers

What quality score is assigned to ungrazed woods according to the given descriptions?

55 Signup and view all the answers

Which of the following has the highest reported quality score among the cultivation methods for small grains?

Straight rows with residue cover Signup and view all the answers

What is one of the main roles of world soils in modern management?

Store carbon to offset CO2 emissions Signup and view all the answers

What environmental condition makes arid lands more susceptible to erosion?

Strong wind activity Signup and view all the answers

Which geographic area represents the smallest proportion of productive lands?

Arid areas Signup and view all the answers

What does wind erosion primarily affect in relation to the eroding soil?

It alters properties and processes Signup and view all the answers

Which equation is used to express the widening of an ephemeral gully with successive rain storms?

$ \Delta W = 1 - exp(-t^*) W_f - W_i$ Signup and view all the answers

Which factor significantly contributes to the amount of soil eroded by gully erosion?

Size of the gully (length and area) Signup and view all the answers

What can result from wind erosion in terms of landscape features?

Development of sand dunes Signup and view all the answers

How does land misuse affect soil over time?

It leads to rapid degradation Signup and view all the answers

Which climate factor primarily affects the magnitude of water erosion?

Precipitation Signup and view all the answers

How does vegetative cover influence water erosion?

It absorbs and intercepts falling raindrops. Signup and view all the answers

What effect does topography have on soil erosion?

It increases with the steepness of the field slope. Signup and view all the answers

Which soil property directly affects the intensity of erosion?

Organic matter content Signup and view all the answers

What is the primary role of precipitation intensity in relation to water erosion?

It is the most critical factor affecting erosion. Signup and view all the answers

How does surface residue cover affect water erosion?

It sponges up raindrops. Signup and view all the answers

Which statement is true regarding soil topography and erosion?

Erosion risk increases on steeper slopes. Signup and view all the answers

Which soil type is more easily eroded according to the content?

Sandy soils Signup and view all the answers

Which cropping system emphasizes alternating different types of crops in the same field?

Crop Rotations Signup and view all the answers

What is a main benefit of no-till farming in soil management?

Enhances soil structural properties Signup and view all the answers

What is the primary purpose of buffer strips in agricultural systems?

Reduce water pollution Signup and view all the answers

Which cropping practice involves growing more than one crop simultaneously in the same field?

Intercropping Signup and view all the answers

What is an expected outcome of agroforestry systems on soil erosion?

Reduction in soil erosion Signup and view all the answers

Which factor does NOT influence the effectiveness of filter strips?

Type of irrigation used Signup and view all the answers

What benefit does conservation tillage provide compared to conventional tillage?

Maintains soil moisture levels Signup and view all the answers

Which type of agricultural practice is specifically aimed at improving nutrient cycling?

Crop Rotations Signup and view all the answers

What is NOT a potential challenge of no-till farming?

Increased soil erosion Signup and view all the answers

What is an essential consideration when designing a riparian buffer?

Type of vegetation used Signup and view all the answers

Which practice directly enhances soil biological properties in agriculture?

Cover Crops Signup and view all the answers

Which mechanism is primarily focused on pollutant removal in agricultural runoff management?

Buffer Strips Signup and view all the answers

Which system can have a positive impact on decreasing nutrient erosion into aquatic ecosystems?

Agroforestry Signup and view all the answers

What is a benefit of utilizing contour farming?

Prevents soil erosion Signup and view all the answers

Study Notes

Soil Erosion

1.8.1 Soil Erosion in Africa and Haiti: Soil erosion is a significant issue in Africa and Haiti.
1.8.2 Drylands: Drylands are particularly vulnerable to wind erosion.
1.8.3 Magnitude of Wind Erosion: The magnitude of wind erosion is influenced by factors such as wind velocity, soil texture, and vegetation cover.
1.9 Current Trends in Soil and Water Conservation: Soil and water conservation practices are crucial for mitigating erosion and ensuring sustainable land management.

Water Erosion

2.1 Types: Water erosion occurs in various forms.
- 2.1.1 Splash Erosion: The impact of raindrops on soil dislodges particles, leading to splash erosion.
- 2.1.2 Interrill Erosion: Interrill erosion involves small, shallow channels forming between rills.
- 2.1.3 Rill Erosion: Rill erosion involves the formation of small, well-defined channels, often visible.
- 2.1.4 Gully Erosion: Gully erosion is characterized by the development of deep, well-defined channels.
- 2.1.5 Tunnel Erosion: Tunnel erosion occurs when water infiltrates beneath the soil surface and erodes the soil from within.
- 2.1.6 Streambank Erosion: Streambank erosion occurs along the edges of streams and rivers, where flowing water undercuts the banks.
2.2 Processes: Water erosion processes involve the detachment and transport of soil particles.
2.3 Factors: Factors influencing water erosion include rainfall intensity, soil properties, vegetation cover, and topography.
2.4 Agents: Water is the primary agent of water erosion.
2.5 Rainfall Erosivity: Rainfall erosivity is a measure of the potential of rainfall to cause soil erosion.
2.6 Runoff Erosivity: Runoff erosivity refers to the ability of runoff water to detach and transport soil particles.
- 2.6.1 Estimation of Runoff: Various methods are used to estimate runoff volume and peak runoff rates, such as the Rational method or the SCS Curve Number method.
- 2.6.2 Time of Concentration: The time of concentration is the time it takes for water to flow from the most distant point in a watershed to the outlet.
- 2.6.3 Runoff Volume: Runoff volume refers to the total amount of water that flows over a watershed in a given time.
- 2.6.4 Characteristics of the Hydrologic Groups: Soils are grouped based on their infiltration characteristics. These groups affect runoff volume and peak rates.
- 2.6.5 Peak Runoff Rate: The peak runoff rate is the maximum rate at which water flows over a watershed.
2.7 Soil Properties Affecting Erodibility: Various soil properties influence its susceptibility to erosion.
- 2.7.1 Texture: Soil texture, describing the proportions of sand, silt, and clay, affects soil erodibility.
- 2.7.2 Structure: Soil structure, the arrangement of soil particles, influences water infiltration and runoff, thus affecting erodibility.
- 2.7.3 Surface Sealing: Surface sealing is the formation of a compacted layer on the soil surface that reduces infiltration and increases runoff.

Why Conserve Soil?

Soil is a vital resource for human survival and is essential for food production, fiber production, and other ecosystem services.
Soil is a finite resource, meaning that it cannot be replenished at the same rate at which it is being lost.
The loss of soil through erosion, compaction, and salinization is a serious threat to agricultural production, and ultimately, sustainability.

Soil Management

Soils are managed to meet increasing food demands, filter air, purify water, and store carbon.
Soil is a non-renewable resource over the human timescale, meaning it can't be replenished quickly enough to keep up with our needs.
Land misuse leads to rapid soil degradation.
Productive lands are finite and less abundant in humid areas compared to dry subhumid and semiarid areas.
Wind can move and erode soil up and down slopes, polluting both air and water.
Arid areas are more prone to wind erosion than humid ecosystems, but any cultivated soil can be eroded by wind in windy environments.
Wind erosion damages the eroding soil and negatively impacts nearby areas where deposition occurs.
Landscapes susceptible to wind erosion often have wind ripples.

Gully Formation

Gully widening from repeated rainfall can be calculated using a formula that takes into account initial and final channel width, and erosion rate.
The total amount of soil eroded by gullies can be estimated by measuring gully size and relating it to soil bulk density.

Water Erosion Factors

Climate factors like precipitation, humidity, temperature, evapotranspiration, solar radiation, and wind velocity influence water erosion.
Precipitation is the primary driver of water erosion, with its amount, intensity, and frequency determining the erosion's magnitude.
Vegetative cover reduces erosion by intercepting, adsorbing, and slowing down the erosive energy of raindrops.
Soil topography determines runoff velocity and influences erosion.
Convex fields erode more readily than concave areas due to surface creeping of soil by gravity.
Soil properties such as texture, organic matter content, macroporosity, and infiltration affect erosion.
Plant morphology, like its height and canopy structure, impacts the effectiveness of vegetation cover in reducing erosion.
Antecedent water content influences erosion by defining the available pore space for rainwater absorption.
Soil aggregation affects the rate of detachment and transportability of soil particles.
Clay particles transport more easily than sand.

Runoff Erosivity

Runoff erosivity is the potential of runoff to cause erosion, depending on factors like rainfall intensity, slope, and soil properties.
Higher rainfall intensity and steeper slopes increase runoff erosivity.
Different soil types have varying runoff erosivity, with coarse-textured soils generally having higher runoff erosivity due to lower infiltration rates.
Land management practices like crop rotations, cover crops, and contour farming can reduce runoff erosivity, leading to lower erosion rates.

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Description

Explore the critical issues of soil erosion, focusing on regions like Africa and Haiti. This quiz covers the types of water erosion, including splash, interrill, rill, and gully erosion, as well as factors influencing wind erosion. Additionally, understand the importance of soil and water conservation practices for sustainable land management.