Question 11 pts Biological N fixation only occurs in leguminous plants Flag this

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Question 11 pts

Biological N fixation only occurs in leguminous plants

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Question 21 pts

High activity clays are excellent for building homes with foundations.

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Question 31 pts

The quantity of biomass carbon (living biomass) is related to the annual amount of plant residue made by primary producers.

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Question 43 pts

You collect a soil core from the field under natural field conditions as would be present after a week of prolonged rainfall, and measure the following properties of the soil.

Total Volume of the intact core (VT, cm3)  300 cm3

Mass or weight of moist soil (ms + mw, g) 550 g

Mass or weight of the soil after drying (ms, g) 400 g

Water Density (g/cm3) 1.0 g/cm3

What is the value for the “dry” bulk density (g/cm3) for your soil sample?

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Question 52 pts

Which of the following would be effective at lowering the pH of a soil currently having a pH of 8.5? Select all that are true.

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Question 62 pts

Which statements best describe the term granular structure? Select all that are true.

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Question 72 pts

Physical weathering processes _____________.

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Question 82 pts

The hydrometer method of determining soil texture is based on Stoke’s law for the settling of particles in a liquid medium. Which of the following influences the rate at which a soil particle settles? Select all that are true.

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Question 92 pts

The soil forming factors operate independently from one another.

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Question 102 pts

A soil moisture regime tells you:

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Question 112 pts

Which of the soil components listed below has the greatest capacity for pH-dependent nutrient exchange?

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Question 122 pts

The layers of contrasting material found when one digs a hole in the ground are called___________.

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Question 132 pts

If you were describing a soil that had more organic material than it had mineral material, you would most likely classify that soil to which order?

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Question 142 pts

Prior to the 1920s, biological N fixation was the primary source of N used to maintain and sustain the fertility of agricultural soils. In order for this form of N to be used by plants, it must be ________ ?

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Question 152 pts

You determine that a soil has 52% sand and 10% silt size particles. Using a texture triangle you determine that this soil has                            [ Select ]                       ["sandy clay", "clay loam", "sandy clay loam"]         texture and                            [ Select ]                       ["62", "16", "38"]         percent clay.

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Question 162 pts

The infiltration rate (cm/h) of a soil with a high portion of water stable aggregates would be expected to _____________ even after a prolonged period of rainfall.

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Question 172 pts

Nitrate is the most mobile form of nitrogen in the soil and would be expected to have the highest availability to plants. Why is nitrate not used as the sole source of nitrogen in most common manufactured fertilizers ?

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Question 182 pts

Select all that are true: The best way to stimulate the activities of Earthworms is to _____________ .

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Question 192 pts

The loam textural class is not centered at 33% clay, 33% silt, and 33% sand because loam is based on equality of the functions of sand, silt, clay in soil and it takes less clay to express its functions than it does the other two.

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Question 202 pts

Which of the following statement(s) is true for a soil with a low pH value? Select all that are true.

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Question 212 pts

Visualize a soil that is very shallow to bedrock and well drained. The soil texture is loam and the slope of the land is approximately 1-3%. Which of the following uses is most appropriate for this soil?

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Question 222 pts

Which of the following Munsell soil colors would indicate a soil with the greatest amount of organic matter in it?

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Question 232 pts

Keeping disturbed soil covered with mulch or an erosion blanket serves which of the following purposes? Select all that are true.

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Question 242 pts

Cyanobacteria found as free-living organisms, or as a symbiotic partners in a lichen, are sometimes referred to as "pioneering" species for their ability to:

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Question 252 pts

What is the dominant gas released from the soil when aerobic mineralization of the organic residues takes place?

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Question 262 pts

The majority of the decomposition of plant residues is accomplished by which of the following groups of organisms?

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Question 272 pts

Soils in which one of the following suborders would be more likely to occur in Alaska than in Texas?

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Question 282 pts

Which of the following is not a soil-forming (pedogenic) process?

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Question 292 pts

Arthropods, mesofauna detritivores, partially digest plant residues and produce fecal pellets with significant remaining food value. It is for this reason they are commonly referred to as:

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Question 302 pts

Biological processes largely influence the formation of water stable aggregates. Which of the following factors play a role in water stable aggregation? Select all that are true.

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Question 312 pts

Farmers have used dung and cow manure to supply N and other nutrients to plants since the beginning of agriculture, over 14,000 years ago. What process still has to be operating before the organic N in manure is available to plants?

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Question 322 pts

The pink/red color of rhizobium root nodules signifies the presence of a protein known as leghemoglobin. The major function of this molecule is to _________ .

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Question 332 pts

Earthworm middens can be observed near to, or covering the entrance to their burrows. They can be easily recognized as ___________.

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Question 342 pts

A soil with the taxonomic designation "vertic hapludalf" is ____________.

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Question 352 pts

What is CEC?

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Question 362 pts

Recall that we describe soil colors using the Munsell system. Which of the following sets of soil color terms consists of only Munsell hues?

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Question 372 pts

A “soil profile” consists of _______________.

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Question 382 pts

Which of the following is not one of the functions of soils?

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Question 392 pts

Which of the following terms refers to a soil's texture?

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Question 402 pts

Visualize a deep soil profile containing clays that shrink when dry and expand when wet. A person thinking about developing on this land would best do which of the following?

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Question 412 pts

As bulk density increases what is the effect on the soil’s porosity?

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Question 422 pts

Which of the following soil orders is matched correctly with its properties?

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Question 432 pts

"When there is adequate available soil N for plant uptake, the need to form nodules is minimal. This is because _________?"

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Question 442 pts

"The mycorrhizal association is a symbiotic relationship, which occurs with most higher plant species and certain fungi. This association carries with it benefits and costs for both partners. The fungi receives sugars from the higher plant and does not have to compete with saprophytic fungi for food sources. The plant benefits from ____________ ?"

Select all that are true.

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Question 452 pts

Which soil order below is most likely to have a high CEC value (say 43 cmolc/kg) due primarily to permanently charged exchange complexes?

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Question 462 pts

In the presence of increasing sodium ions, clay in soils will tend to _____________

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Question 472 pts

The majority of the arthropod activity is found ____________ ?

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Question 482 pts

Regardless of whether you use indicator drops, litmus paper, or a pH electrode to measure pH, what you are actually measuring is:

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Question 492 pts

Earthworms thrive in soils with which of the following attributes? Select all that are true.

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Question 502 pts

Silicate clay accumulation is most common in the ____________ horizon.

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Question 512 pts

The pores between mineral grains and humus form a network of irregular “capillary tubes.” When a soil column is saturated from the bottom, water will move upward in the soil column and reach a final maximum height. This height is related to which of the following factors? Select all that are true.

True

Explanation / Answer

Question-11

Ans- True

Explanation- By the help of a type of soil bacteria (called rhizobia) leguminous plants can fix the Nitrogen in their roots in a form that can be usable by the plants and also animals. The reationship between the leguminous plant and rhiozobia is called symbiotic relation.

Question- 21

Ans- False

Explanation- High activity clays contain illite and montmorillonite in it.

Question- 52

Ans- adding pine needles, adding elemental sulfur and adding organic matter can lower the PH of soil.

Question- 72

Ans- Physical weathering process break down rocks and sediments into smaller pieces.

Explanation- Physical weathering is simply a preocess where the rocks break down into smaller pieces without changing its chemical composition.

Question- 122

Ans- soil Horizon

Question- 132

Ans- Histosol

Question- 502

Ans- B

Explanation- Accumulation occurs at the Zone of illuviation i.e. the B horizon where as the leaching process occurs at the Zone of elluviation i.e the A,E horizon.

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