CCA - Certified Crop Advisor Soil and Water Conservation Questions and Answers 1 — Questions and Answers
Question 1: A producer is experiencing concentrated flow erosion forming small, defined channels across a sloping field after heavy rainfall. These channels are shallow enough to be removed by normal tillage operations. What is the most accurate term for this type of water erosion?
- Sheet erosion
- Rill erosion (Correct answer)
- Gully erosion
- Splash erosion
Correct answer: Rill erosion
Rill erosion is characterized by the formation of small, well-defined channels caused by concentrating runoff. A key feature is that these channels, or rills, are small enough to be smoothed over by standard tillage equipment. Sheet erosion is the more uniform removal of soil in a thin layer, gully erosion involves larger channels too deep to be crossed by farm machinery, and splash erosion is the initial detachment of soil particles by raindrop impact.
Question 2: A farmer wants to implement contour farming to reduce soil erosion on a field with a 6% slope. Which of the following is the most critical principle for the successful implementation of this practice?
- Establishing a series of broad-based terraces across the slope.
- Planting alternating strips of row crops and sod-forming crops.
- Orienting all tillage and planting operations as close to level across the slope as possible. (Correct answer)
- Installing a grassed waterway down the steepest part of the slope.
Correct answer: Orienting all tillage and planting operations as close to level across the slope as possible.
The fundamental principle of contour farming is to perform all farm operations, including plowing, planting, and cultivating, on or near the contour of the land. This creates hundreds of small ridges or dams that slow water runoff, increase infiltration, and reduce erosion. While terraces, strip cropping, and waterways are also valuable conservation practices, they are distinct from the core concept of contour farming. Contour farming is most effective on slopes between 2% and 10%.
Question 3: Which of the following conservation practices is specifically designed to be a densely vegetated area that intercepts surface runoff from upslope areas to slow water flow, trap sediment, and filter nutrients and pesticides before they reach water bodies?
- Cover crop
- Grassed waterway
- Windbreak
- Filter strip (Correct answer)
Correct answer: Filter strip
A filter strip, also known as a buffer strip, is an area of vegetation established between a potential pollutant source (like a crop field) and a body of water. Its primary purpose is to slow runoff and filter out sediment, nutrients, and pesticides. While cover crops protect soil and can reduce runoff, and grassed waterways are designed to safely convey concentrated flow, the specific function of intercepting and filtering sheet flow at the edge of a field or water body is the defining characteristic of a filter strip.
Question 4: Which of the following is NOT a primary benefit of using cover crops in a soil and water conservation plan?
- Increased soil organic matter
- Reduced soil compaction
- Elimination of the need for subsurface drainage (Correct answer)
- Suppression of weed growth
Correct answer: Elimination of the need for subsurface drainage
Cover crops provide numerous benefits, including increasing soil organic matter, improving soil structure to reduce compaction, and suppressing weeds through competition and allelopathy. However, they do not eliminate the need for subsurface drainage. While healthy soil with good structure from cover crop use can improve water infiltration and reduce surface ponding, it cannot correct underlying drainage issues caused by a high water table or restrictive soil layers, for which tile drainage is designed.
Question 5: A CCA is advising a client on tillage systems. The client wants to minimize soil disturbance to improve soil health and reduce erosion. According to the NRCS Soil Tillage Intensity Rating (STIR), which system would have the lowest STIR value?
- Moldboard plow followed by a finishing disk
- Chisel plow followed by a field cultivator
- No-till planting directly into previous crop residue (Correct answer)
- Strip-till into previous crop residue
Correct answer: No-till planting directly into previous crop residue
The Soil Tillage Intensity Rating (STIR) is a numerical value that quantifies the level of soil disturbance from tillage operations, with lower numbers indicating less disturbance. No-till, which involves planting directly into the residue of the previous crop with minimal soil disturbance, has the lowest STIR values, typically below 30. Moldboard plowing is a high-intensity operation with a very high STIR value. Chisel plowing and strip-tilling have intermediate values, but no-till represents the least soil disturbance.
Question 6: A producer has a natural drainage area in a large field where runoff concentrates, threatening to form a large gully. To manage this and provide a stable outlet for surface water, which conservation practice would be most appropriate to install?
- Contour buffer strips
- A grassed waterway (Correct answer)
- A field border
- Terraces
Correct answer: A grassed waterway
A grassed waterway is a shaped or graded channel that is planted with suitable vegetation to safely convey concentrated water flow at a non-erosive velocity. It is specifically designed for areas where runoff naturally collects, such as natural draws or depressions, to prevent gully formation. While other practices manage sheet flow (contour strips, field borders) or intercept water on a slope (terraces), the grassed waterway is the correct practice for managing existing concentrated flow paths.
CCA - Certified Crop Advisor Soil and Water Conservation Questions and Answers 1
A producer is experiencing concentrated flow erosion forming small, defined channels across a sloping field after heavy rainfall.
These channels are shallow enough to be removed by normal tillage operations.
What is the most accurate term for this type of water erosion?