Question 1

Wind erosion accounts for about what percent of the total soil erosion losses in the United States?

Accepted Answer

Wind erosion accounts for about 35% of the total soil erosion losses in the United States.

Question 2

In one field trial comparing no-till and conventional tillage,soil samples taken after 15 years without liming revealed that the pH of the upper 15 cm was lower on the no-till plot than on the conventional plot.Which of the following most likely accounts for this difference?

Accepted Answer

C

Question 3

In explaining erosion processes to a friend,which of the following would you say about accelerated erosion?

Accepted Answer

Accelerated erosion is significantly influenced by the splash effect of raindrops on bare soil, which can dislodge soil particles and increase erosion rates. This contrasts with natural geological erosion processes, which are typically slower and less influenced by human activities.

Question 4

Conservation tillage systems are said to have all of the following advantages but one over conventional tillage systems

Accepted Answer

Conservation tillage systems often rely on herbicides for weed control, which can be more toxic than mechanical weed control methods used in conventional tillage.

Question 5

The U.S.Department of Agriculture has developed soil-loss tolerance limits (T values)for different soils.Which of the following is the highest T value assigned for most soils in this country (Mg/ha)?

Accepted Answer

The answer of The U.S.Department of Agriculture has developed soil-loss...

Question 6

Which of the USDA land use capability classes (LUC)is most suitable for the production of row crops?

Accepted Answer

Class I lands are the most suitable for the production of row crops because they have the fewest limitations, requiring the least amount of management and conservation practices.

Question 7

The R factor of the Universal soil-loss equation is concerned with _____.

Accepted Answer

The R factor in the Universal Soil Loss Equation (USLE) represents rainfall and runoff, which are climate-related factors influencing soil erosion.

Question 8

You have been asked to produce continuous corn on five different soils using both no-till and conventional management systems.Yields on the no-till and conventional-till systems are about the same on all but one of the soils.In which of the following suborders would the poor-performing soil most likely be classified?

Accepted Answer

Borolls are characterized by clay accumulation in the subsoil, which can lead to poor drainage and aeration. This can hinder root development and ultimately lead to decreased yields in crops. The other suborders listed do not have this characteristic and therefore would be less likely to have a soil that performs poorly under both no-till and conventional management systems.

Question 9

Which of the following statements is true?

Accepted Answer

Rill erosion channels are small enough that they can be smoothed out or removed by ordinary cultivation practices, unlike larger gully erosion channels.

Question 10

A soil has been managed using a no-till system for 10 years following many years of conventional tillage operations.Which of the following changes in surface soil properties would you expect due to the no-till management system?

Accepted Answer

No-till management system helps to increase the organic matter content of the soil. This is because the undisturbed soil allows organic matter to accumulate, and the residue left from previous crops acts as a source of organic matter. Therefore, the organic matter content would increase in the surface soil as a result of the no-till management system. The other options are not expected changes due to no-till management. The earthworm population would likely increase, soil pH would not necessarily increase, aggregate stability would improve due to the increase in organic matter, and bulk density would decrease due to the improved soil structure.

Question 11

The revised universal soil-loss equation (RUSLE)differs from USLE in all ways but one of the following.

Accepted Answer

The answer of The revised universal soil-loss equation (RUSLE)differs from...

Question 12

Wind erosion is generally not affected by _____.

Accepted Answer

Soil pH does not have a significant impact on wind erosion. The other factors listed can affect the susceptibility of soil to wind erosion. Soil moisture can affect the cohesion of soil particles, soil crusting can increase surface roughness and reduce soil detachment, bulk density can affect wind erosion susceptibility by affecting the stability of soil aggregates, and soil texture can impact both soil detachment and deposition.

Question 13

About what percentage of the total non-federal government owned rural lands is considered suitable for cultivation according to USDA land use capability classes (if appropriate management practices are employed)?

Accepted Answer

The answer of About what percentage of the total non-federal...

Question 14

On which of the land use capability classes is suggested use restricted to non-production purposes,only wildlife and recreational purposes being appropriate?

Accepted Answer

Class VIII lands are those that are most severely limited, making them unsuitable for cultivation or any form of agricultural production. The suggested uses for these lands are restricted to non-production purposes, such as wildlife habitat and recreational activities, due to their limitations which may include factors like very steep slopes, poor soils, or other significant constraints.

Question 15

To be classified as a conservation tillage practice,a system must leave at least what portion of the soil surface covered with plant residues?

Accepted Answer

Conservation tillage involves leaving a certain amount of plant residues on the soil surface to protect the soil from erosion, increase soil organic matter, and improve soil structure. The minimum amount of plant residue required to be left on the soil surface to be classified as conservation tillage is 30%. Therefore, choice C is the correct answer.

Question 16

The P factor in the Universal soil-loss equation is concerned with all but one of the following:

Accepted Answer

The P factor in the Universal soil-loss equation is concerned with precipitation and its effect on soil erosion, not contour tillage, strip-cropping, terraces or vegetative covers.

Question 17

"Living" terraces involving rows of deep rooted grasses planted on the contour would be considered as contributing to which factor in the Universal soil-loss equation?

Accepted Answer

The "living" terraces, which involve planting rows of deep-rooted grasses on the contour, contribute to the P factor in the Universal Soil Loss Equation (USLE). The P factor represents the support practice factor, which includes practices that reduce the amount of erosion under specific conditions, such as contour farming, strip cropping, terracing, and cover crops.

Question 18

If you want to maximize the quantity of vegetative cover on soil which of the following tillage practices would you use?

Accepted Answer

No-tillage is the best choice for maximizing vegetative cover on soil as it leaves crop residues on the surface, which helps to retain soil moisture and nutrients, and also provides a protective cover for seeds and plants. Conventional moldboard plow, ridge tillage, strip till, and stubble mulch involve soil disturbance, which can disrupt existing vegetation and reduce the amount of vegetative cover.

Question 19

The universal soil-loss equation (USLE)suggests that soil erosion loss is a product of all but one of the following factors:

Accepted Answer

The USLE factors that contribute to soil erosion loss are climate, slope length, slope steepness, vegetative cover, and soil erodibility. Soil drainage is not a factor included in USLE.

Question 20

Which of the following statements about soil erosion is not true?

Accepted Answer

The answer of Which of the following statements about soil...

Quiz 17: Soil Erosion and Its Control