Soil Erosion & Sedimentation Control Training - Unit 3

Explanation
The best way to prevent erosion is to remove the minimum amount of vegetation and re-establish it as soon as possible. Vegetation, such as plants and trees, plays a crucial role in preventing erosion. The roots of vegetation help hold the soil in place, preventing it from being washed away by water or blown away by wind. By removing as little vegetation as possible and quickly replanting or re-establishing it, the soil can be protected from erosion and its negative effects on the environment.

Explanation
In order to stabilize with vegetation, a critical area should be difficult to disturb. This means that it should be challenging to disrupt the natural state of the area, allowing vegetation to grow and stabilize the soil. Therefore, the correct answer is "difficult, disturbed."

Explanation
A non-critical area is an area on which vegetation can be established without difficulty. This means that the area does not require any special effort or challenges to stabilize the vegetation or provide water for its growth. The vegetation can grow naturally and easily in this area without any complications or obstacles.

Explanation
Sensitive areas are those areas next to lakes or streams that can be easily damaged by sediment. Lakes and streams are vulnerable to sediment runoff, which can negatively impact their water quality and ecosystem. Sediment can clog waterways, smother aquatic plants and animals, and disrupt the natural flow of water. Therefore, it is important to protect these sensitive areas from sediment erosion and runoff to maintain the health and integrity of lakes and streams.

Explanation
Vegetation stabilization can be achieved through two different methods: temporary and permanent. Temporary stabilization refers to the use of short-term measures that provide immediate but temporary stability, such as erosion control blankets or temporary vegetation cover. On the other hand, permanent stabilization involves the use of long-term measures that establish a permanent vegetation cover, such as the planting of trees or the establishment of grasses and shrubs. Both methods have their own advantages and disadvantages depending on the specific needs and conditions of the area requiring stabilization.

Explanation
Legumes furnish nitrogen to the soil, which is an important plant nutrient. Nitrogen is a vital component of proteins, enzymes, and chlorophyll, all of which are essential for plant growth and development. Legumes have a unique ability to form a symbiotic relationship with nitrogen-fixing bacteria in their root nodules. These bacteria convert atmospheric nitrogen into a form that plants can utilize, thus enriching the soil with nitrogen. This makes legumes an excellent choice for crop rotation or cover cropping to improve soil fertility and promote healthy plant growth.

Explanation
When selecting plant materials for stabilization, it is important to consider various factors such as site use and maintenance, slopes, soil, climate, and soil moisture content. These factors play a crucial role in determining the suitability of plant materials for stabilizing the area. The site use and maintenance factor helps ensure that the selected plants can thrive in the specific site conditions and are compatible with the intended use of the area. Slopes are important to consider as they can affect the stability of the plants and their ability to prevent erosion. Soil conditions, including its composition and fertility, are crucial for the successful growth of plant materials. Climate is another important factor as it determines the environmental conditions that the plants will be exposed to, including temperature, rainfall, and sunlight. Lastly, soil moisture content is important to consider as it affects the water availability for the plants. Overall, considering these factors ensures that the selected plant materials are suitable for stabilizing the specific site.

Explanation
The on-site soil conditions that should be considered include soil moisture content, fertility, and acidity. Soil moisture content is important because it affects the availability of water to plants and can impact their growth. Fertility refers to the nutrient content of the soil, which is crucial for plant health and productivity. Acidity, or pH levels, is important because it affects the availability of nutrients in the soil and can impact plant growth. Nitrogen content is not mentioned in the answer, so it is not applicable in this case.

Explanation
Subsoils are generally low in fertility and are acidic. This means that subsoils typically have a lack of essential nutrients required for plant growth and development, making them less fertile. Additionally, the acidity of subsoils can further hinder nutrient availability and uptake by plants, further contributing to their low fertility.

Explanation
Topsoil should be saved at the beginning of grading operations for later use. This is because topsoil is the uppermost layer of soil that is rich in nutrients and organic matter, making it valuable for plant growth. By saving the topsoil, it can be reused in landscaping or gardening projects, helping to maintain soil fertility and reduce the need for additional fertilizers. Additionally, saving topsoil can also help prevent erosion and soil degradation, promoting sustainable land management practices.

Explanation
When slopes are steeper, the vertical structures may be more effective to control erosion than vegetation. This is because vertical structures, such as retaining walls or gabion baskets, can provide a stronger barrier against the force of gravity and water flow on steep slopes. Vegetation alone may not be able to withstand the erosive forces on steep slopes and may be easily uprooted or washed away. Therefore, using vertical structures with a slope ratio of 2:1 is likely to be more effective in preventing erosion on steep slopes.

Explanation
Most grasses prefer a soil pH of no lower than 5.5, while legumes prefer a pH no lower than 6.5. This means that grasses can tolerate slightly more acidic conditions than legumes.

Explanation
Soil testing is a method that can determine the amount of lime and/or fertilizer required for good vegetative growth. By analyzing the composition and nutrient levels in the soil, soil testing provides valuable information about the soil's fertility and pH levels. This information helps farmers and gardeners make informed decisions about the type and quantity of lime and fertilizer to apply, ensuring optimal conditions for plant growth.

Explanation
Soil slippage occurs when the soil loses its stability and slides down a slope. Poor bonding refers to the lack of cohesion between soil particles, which weakens the soil structure and makes it prone to slippage. Slope steepness plays a role as well, as steeper slopes increase the force of gravity acting on the soil, making it more likely to slide. High moisture content also contributes to soil slippage, as it reduces the friction between soil particles and makes the soil more prone to movement.

Explanation
The correct answer includes four methods for establishing vegetation: seeding, sprigging, sodding, and planting a root-balled or container grown shrub or tree. These methods involve different techniques to introduce and grow vegetation in an area. Seeding refers to the process of sowing seeds directly into the soil, sprigging involves planting small sections of grass or plants, sodding is the process of laying down pre-grown grass or plants in the form of sod, and planting a root-balled or container grown shrub or tree involves transplanting a fully grown plant with its root system intact. These methods provide options for establishing vegetation based on the specific needs and conditions of the area.

Explanation
Sprigging involves planting sprigs of live vegetation. Sprigs are small sections of plants that include stems, leaves, and roots. This method of planting is commonly used for grasses and groundcovers, where small sections of the plant are placed in the soil to establish new growth. Unlike seedlings, which are young plants grown from seeds, sprigs are already mature sections of plants that can quickly establish and grow in the desired area. Therefore, the correct answer for this question is sprigs.

Explanation
Seeding and mulching should be done as soon as the seedbed is ready because seeding refers to the process of planting seeds in the soil to establish new plants, while mulching involves covering the soil with a layer of organic material to conserve moisture, suppress weeds, and regulate soil temperature. By seeding and mulching early, the seeds have a better chance of germination and the mulch helps to create a favorable environment for the seeds to grow by providing moisture and reducing competition from weeds.

Explanation
Mulch is a material that is spread over the soil surface to insulate it from extreme temperatures, such as intense heat and cold. It acts as a protective layer, preventing the soil from losing moisture due to evaporation and reducing the impact of temperature fluctuations. Therefore, mulch helps to conserve moisture in the soil, making it the correct answer.

Explanation
Straw is the most commonly used mulch material because it is readily available, affordable, and easy to apply. It helps to retain moisture in the soil, suppress weed growth, and regulate soil temperature. Straw also breaks down slowly, providing nutrients to plants over time. Additionally, it is lightweight and can be easily moved or spread around plants. Overall, straw is a versatile and effective mulch option for gardeners and landscapers.

Explanation
The two types of maintenance required for vegetation stabilization are follow-up and periodic. Follow-up maintenance refers to the ongoing care and monitoring of the vegetation after it has been initially established, such as regular watering, pruning, and weeding. Periodic maintenance, on the other hand, involves scheduled and less frequent activities like fertilizing, aerating, and reseeding to ensure the long-term health and stability of the vegetation.

Explanation
Areas planted in the fall should be inspected in the spring because this is the time when the plants have had time to establish themselves and start growing. By inspecting in the spring, any issues or problems with the plants can be identified and addressed early on, allowing for necessary actions to be taken to ensure their health and proper growth. Additionally, spring is a critical time for many plants as they enter their active growing season, making it important to assess their condition and provide any necessary care or maintenance.