1 $Which of the following processes describes the conversion of organic nitrogen into plant-available inorganic forms ()?$

A.

Nitrification

B.

Mineralization

C.

Immobilization

D.

Denitrification

2 $In the process of nitrification, which bacteria are primarily responsible for oxidizing ammonium () to nitrite ()?$

A.

Nitrobacter

B.

Nitrosomonas

C.

Thiobacillus

D.

Rhizobium

3 $Under anaerobic conditions, nitrate () is reduced to gaseous nitrogen forms (). What is this process called?$

A.

Ammonification

B.

Volatilization

C.

Denitrification

D.

Fixation

4 $Which form of nitrogen is most susceptible to leaching losses in soil due to its negative charge repelling soil colloids?$

A.

B.

C.

Organic N

D.

5 $Ammonia volatilization is represented by which of the following chemical equilibria?$

A.

B.

C.

D.

6 $At what C:N ratio does net immobilization of nitrogen generally occur in the soil?$

A.

< 10:1

B.

< 20:1

C.

> 30:1

D.

Exactly 15:1

7 $Which enzyme is essential for biological nitrogen fixation to break the triple bond of dinitrogen ()?$

A.

Urease

B.

Nitrogenase

C.

Phosphatase

D.

Amylase

8 $What is the dominant ionic form of phosphorus available to plants in acidic soils (pH < 6.0)?$

A.

B.

C.

D.

9 $In highly acidic soils, phosphorus availability is primarily limited by fixation with which elements?$

A.

Calcium and Magnesium

B.

Iron and Aluminum

C.

Potassium and Sodium

D.

Sulfur and Chlorine

10 $In alkaline or calcareous soils, phosphorus fixation occurs primarily through the formation of insoluble compounds with:$

A.

Aluminum

B.

Iron

C.

Calcium

D.

Manganese

11 $The movement of phosphorus from soil to plant roots occurs primarily via:$

A.

Mass flow

B.

Diffusion

C.

Root interception

D.

Infiltration

12 $Which clay mineral is most associated with the fixation of Potassium () in its interlayers?$

A.

Kaolinite

B.

Illite / Vermiculite

C.

Gibbsite

D.

Goethite

13 $Potassium is absorbed by plants primarily as:$

A.

B.

C.

D.

14 $The concept of 'Luxury Consumption' is most commonly associated with which macronutrient?$

A.

Nitrogen

B.

Phosphorus

C.

Potassium

D.

Calcium

15 $Which form of Calcium is part of the cation exchange capacity (CEC) and easily available to plants?$

A.

Mineral Calcium (Feldspars)

B.

Exchangeable Calcium ()

C.

Precipitated Calcium Carbonate

D.

Organic Calcium

16 $The primary mechanism for Calcium and Magnesium transport to plant roots is:$

A.

Diffusion

B.

Mass Flow

C.

Chemotaxis

D.

Fixation

17 $Magnesium acts as the central atom in which vital plant molecule?$

A.

ATP

B.

Chlorophyll

C.

Cytochrome

D.

DNA

18 $In which form is Sulphur primarily absorbed by plant roots?$

A.

B.

C.

D.

19 $The transformation of elemental sulfur () to sulfate () in soil is an oxidation process primarily carried out by:$

A.

Rhizobium

B.

Thiobacillus

C.

Azotobacter

D.

Mycorrhizae

20 $Which nutrient is a structural component of the amino acids cysteine, cystine, and methionine?$

A.

Potassium

B.

Phosphorus

C.

Sulphur

D.

Magnesium

21 $Micronutrients are generally most available to plants in which pH range?$

A.

pH 4.0 - 5.0

B.

pH 5.5 - 7.0

C.

pH 7.5 - 8.5

D.

pH > 9.0

22 $Which micronutrient is unique because its availability increases as soil pH increases (becomes more alkaline)?$

A.

Iron ()

B.

Manganese ()

C.

Molybdenum ()

D.

Zinc ()

23 $Iron deficiency in plants, often observed in calcareous soils, is commonly known as:$

A.

Iron toxicity

B.

Lime-induced chlorosis

C.

Bronzing

D.

Necrosis

24 $Which organic compounds are commonly used in fertilizers to prevent metal micronutrients (like Fe, Zn) from precipitating in the soil?$

A.

Surfactants

B.

Chelates

C.

Polymers

D.

Nitrification inhibitors

25 $Boron is primarily absorbed by plants in the form of:$

A.

B.

(Boric acid)

C.

D.

26 $Which micronutrient is essential for the synthesis of the plant hormone auxin (Indole Acetic Acid)?$

A.

Copper

B.

Zinc

C.

Manganese

D.

Chlorine

27 $The reduction of Manganese from (insoluble) to (soluble) is favored by which soil condition?$

A.

High pH (Alkaline)

B.

High Redox Potential (Aerobic)

C.

Low Redox Potential (Waterlogged/Anaerobic)

D.

Drought

28 $Which form of Chlorine is absorbed by plants?$

A.

(gas)

B.

(Chloride ion)

C.

D.

29 $Nickel () is the most recently classified essential micronutrient. It is a critical component of which enzyme?$

A.

Nitrogenase

B.

Urease

C.

Peroxidase

D.

Nitrate Reductase

30 $An antagonistic relationship exists between Phosphorus () and which micronutrient, where high P levels can induce a deficiency?$

A.

Boron

B.

Zinc

C.

Molybdenum

D.

Chlorine

31 $The term 'Mulder's Chart' refers to:$

A.

Soil texture classification

B.

Nutrient interactions (Synergism and Antagonism)

C.

pH vs Nutrient Availability

D.

Crop rotation schedules

32 $High levels of Potassium () fertilizer often induce a deficiency in which secondary nutrient due to cation competition?$

A.

Sulphur

B.

Magnesium

C.

Phosphorus

D.

Chlorine

33 $Which ratio is often analyzed to assess the potential for Potassium availability relative to other cations?$

A.

C:N ratio

B.

N:P:K ratio

C.

K / (Ca + Mg) ratio

D.

Fe:Mn ratio

34 $What happens to Phosphorus availability in soil if Calcium Carbonate () is added in excess?$

A.

Availability increases drastically

B.

Availability decreases due to fixation as Ca-phosphates

C.

No change occurs

D.

Phosphorus becomes volatile

35 $Copper () binds very tightly to which soil component, often leading to deficiency in peat or muck soils?$

A.

Sand particles

B.

Organic Matter

C.

Kaolinite clay

D.

Water

36 $Which nutrient interaction is generally considered Synergistic?$

A.

N and K (at proper levels)

B.

Ca and Mg

C.

P and Zn

D.

Na and K

37 $The conversion of organic Sulfur to inorganic Sulfate is dependent on:$

A.

Only chemical hydrolysis

B.

Microbial activity (C:S ratio)

C.

Leaching

D.

Volatilization

38 $What is the oxidation state of Iron in the ferrous form, which is absorbed by plants?$

A.

B.

C.

D.

39 $Which of the following equations represents the hydrolysis of Urea in the soil?$

A.

B.

C.

D.

40 $Phosphorus moves through the soil solution to the root surface primarily over distances of:$

A.

Several centimeters

B.

Very short distances (cm)

C.

Meters

D.

It does not move

41 $Which of the following soil colloid types has the highest affinity for specifically adsorbing Phosphate anions?$

A.

Humus

B.

2:1 Clays (Montmorillonite)

C.

Amorphous Fe and Al oxides (Allophane)

D.

Sand

42 $Manganese toxicity is most likely to occur in:$

A.

Well-limed soils

B.

Acidic soils with pH < 5.5

C.

Sandy soils

D.

Calcareous soils

43 $The 'Quantity/Intensity' (Q/I) relationship is typically used to describe the buffering capacity of which nutrient?$

A.

Nitrogen

B.

Potassium

C.

Sulfur

D.

Boron

44 $Which anion is known to competitively inhibit the uptake of Molybdenum?$

A.

Sulfate ()

B.

Nitrate ()

C.

Chloride ()

D.

Phosphate ()

45 $The structural lattice of chlorophyll contains 4 Nitrogen atoms and 1 Magnesium atom. This highlights the importance of N-Mg interaction in:$

A.

Root growth

B.

Photosynthesis

C.

Water uptake

D.

Respiration

46 $In the context of nutrient movement, 'Mass Flow' relies primarily on:$

A.

Concentration gradient

B.

Plant transpiration rate

C.

Root growth rate

D.

Soil temperature

47 $Which element is involved in osmoregulation and stomatal opening/closing?$

A.

Calcium

B.

Potassium

C.

Phosphorus

D.

Iron

48 $The primary reservoir of Nitrogen in most surface soils is:$

A.

Mineral rocks

B.

Organic Matter

C.

Soil atmosphere

D.

Groundwater

49 $Which nutrient is required for the synthesis of the enzyme urease?$

A.

Zinc

B.

Nickel

C.

Cobalt

D.

Iron

50 $Soluble salts in soil can impede water uptake. Which interaction explains the mitigation of sodium () toxicity by adding Calcium ()?$

A.

Synergism

B.

Ion Exchange / Displacement

C.

Precipitation

D.

Fixation

Unit 2 - Practice Quiz