What are the six most important factors in determining Ca+2 availability to plants?

1. Total Ca supply 2. Soil pH 3. CEC 4. % Ca+2 saturation on CEC 5. Type of soil clay 6. The ratio of solution Ca+2 to other cations

Section 2 - Essential Plant Nutrients Flashcards by Brandon Holland

List three ways to make Se fertilization acceptable.

Se topdressing is not applied
High Se levels in edible animal tissue are prevented
Protection against Se deficiency is provided for at least one grazing season following application during the dormant season

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S is absorbed by plant roots almost exclusively as ___.

sulfate (SO₄^‐2)

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Name four ways Mg is found in soil solution.

lost in percolating water
absorbed by microorganisms
adsorbed on the CEC
reprecipitated as a secondary mineral

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P tends to stay where it’s applied and not move through the soil, unlike N and K which can be lost from the soil solution. P will accumulate thus N-P-K fertilizer ratios need to be adjusted to P=0.

True

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Rates of reaction with P are ___ therefore plants have a chance to take it up

slow

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As organic P is mineralized to inorganic P or as P is added to soil, inorganic P in solution (H₂PO₄^‐/HPO₄^‐2) not absorbed by roots or immobilized by microorganisms can be adsorbed to mineral surfaces or precipitated as secondary P compounds

True

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The concentration of the inorganic P in the soil solution is the most important single factor governing the availability of plants. Uptake of H₂PO₄^- is more rapid than HPO₄^-2 with the former being most abundant at pH < 7.2.

True

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Name 7 factors that affect P mineralization and immobilization

Microbial activity
Residues C/P ratio
Soil temperature
Soil aeration
Soil pH
Soil moisture
P fertilization

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What are the 5 available soil solutions for K Loss?

1) Adsorption
2) Leaching
3) Plant removal
4) Erosion
5) Fixation

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P concentrations in plants range between 0.1 and 0.5%, considerably ___ than N and K. Plants absorb either H2PO4‐ or HPO4‐2 (orthophosphate) depending on soil pH.

lower

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Organic P represents about __% of total soil P and typically varies between 15 and 80%.

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Solution K⁺ in ___‐textured soils may be much lower than in ___‐textured soils at any given level of exchangeable K.

fine

course

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Soil moisture: Mo deficiency is accentuated under ___ ___.

dry conditions

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K is absorbed by plant roots as __ and tissue concentration ranges from _ to _% in dry matter.

K+

1 to 5%

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___ soils need to be limed first before adding K

Acidic

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The soil pH of maximum availability for P is pH _._.

6.5

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Soils containing ___, ___, or ___ have more K than soils containing mainly kaolinitic clays, common in highly weathered soils.

vermiculite, montmorillonite, or mica

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Excessive Water and Poor Aeration: Any compact, fine-textured, calcareous soil can be Fe ___.

deficient

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Excessive Water and Poor Aeration: Waterlogged soils exhibit ___ O₂ and lower redox potential, which increases soluble Mn⁺². Mn availability can be ___ by poor aeration in compact soils and by local accumulation of CO₂ around roots and other soil microsites.

reduced

increased

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___ is a major component of bones and teeth and is important for lactating animals.

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The addition of residues low in P may ____ immobilization if there is not enough P to degrade residues.

stimulate

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Typical K deficiency symptoms in alfalfa consist of ___ ___ on the leaf edges, whereas ___ and ___ of the leaf edges are observed with corn and other grasses.

white spots

chlorosis and necrosis

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Organic Cu: Most of the soluble Cu⁺² in surface soils is ___ ___ and is more strongly bound to OM than any other micronutrient.

organically complexed

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S in Earth’s crust averages ≈ _.__%, comparable to P.

0.05

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K in primary mineral structure is \_\_\_

unavailable

Soils do have a lot of P (top 50 cm) but are mostly unavailable due to \_\_\_

fixation

The extent ___ \_ fixation depends on many factors, most importantly on soil minerals.

inorganic K

What are eight factors influencing inorganic P fixation in soils?

1. Soil minerals 2. Soil pH 3. Cation and anion effects (NH₄⁺/NO₃^-) 4. Soil OM 5. Time and temperature 6. Soil moisture 7. Fertilizer P management 8. Considerations (rate, time, type, method)

What are the six most important factors in determining Ca⁺² availability to plants?

1. Total Ca supply 2. Soil pH 3. CEC 4. % Ca⁺² saturation on CEC 5. Type of soil clay 6. The ratio of solution Ca⁺² to other cations

Exchangeable K is highly correlated to K availability to plants as exchangeable K \_\_\_, fertilizer K recommendations \_\_\_.

increases decreases

Soil Solution Mn: ___ is the common form in solution; its concentration decreases ___ \_\_\_ for each unit increase in pH.

Mn⁺² one hundredfold

Organic wastes are excellent sources of \_\_\_-\_\_\_ P, with manure accounting for \_\_% of organic P applied to cropland

plant-available 98

Surface adsorption and precipitation reactions are collectively called ___ \_\_\_ or retention

P fixation

Name eight nutrients that are immobile in plants. Deficiency symptoms show up on ___ leaves first

1. Ca 2. Cu 3. Mn 4. Zn 5. Fe 6. Mo 7. B 8. S younger

Sulfur is essential for \_\_\_

protein

Which of the following is not true about liming acid soils by applying CaCO3? A) It supplies Ca to plants B) It corrects soil acidity C) It increases crop yield D) It increases acidic cations saturation of soil colloids

D) It increases acidic cations saturation of soil colloids

What are the three Secondary Macronutrients?

1. S 2. Ca 3. Mg

K is important for many crop quality characteristics due to its involvement in the ___ and ___ of ___ to plant reproductive and storage organs and subsequent conversion into carbohydrates, proteins, oils, and other products.

synthesis and transport of photosynthates

Soil Texture: Coarse-textured, well-drained soils are ___ in B, and crops with a ___ requirement respond to B applications. Sandy soils ___ respond in the same manner.

low high don't

The quantity of K transported to the root surface by ___ and ___ \_\_\_ is related to K intensity.

diffusion and mass flow

Adequate ___ increases straw strength in cereals and increases N₂‐fixation capacity of legumes.

Texture: The potential for Cu deficiency is high in ___ leached, \_\_\_-textured soils.

excessively course

Which of the following does not affect Fe availability in soil solution? A) crop removal B) soil organic matter C) soil pH D) soil N₂ gas

D) soil N₂ gas

Co in Soils: Average total Co concentration in Earth’s crust is ≈ __ ppm. Co in soils typically range from 1 to 70 ppm and average about 8 ppm.

Cu Deficiency and Toxicity: Although not as common as with other micronutrients, Cu deficiencies do occur in sensitive crops on low Cu soils. Cu toxicity symptoms include reduced ___ \_\_\_, poorly developed and discolored root systems, and ___ \_\_\_.

shoot vigor leaf chlorosis

Soil S is present in organic and inorganic forms, although ≈ \_\_\_% of total S in noncalcareous surface soils exists as ___ \_\_.

90% organic S

Soil texture: In sandy, low OM soils, MoO₄^-2 retention is \_\_\_.

low

Mineral Mo: The average Mo concentration in the earth’s crust is __ ppm, and typically ranges from 0.2 to 5 ppm in soils. Soil minerals controlling solution MoO₄^-2 concentration are PbMoO₄ and CaMoO₄. CaMoO₄ predominates in both acidic and calcareous soils.

The percentage of P₂O₅ in Ca₃(PO₄)₂ is: (use Ca=40, P=31, and O=16 g molecular weights) A) 20 B) Impossible to calculate since there is no P2O5 in the formula. C) 23 D) 46

D) 46

Soil OM: Although lime-induced Fe deficiency occurs in ___ soils, low-OM ___ soils are often in plant-available Fe.

wet calcareous

Mg constitutes ~\_% of Earth’s crust; however, total soil Mg content ranges from 0.1% in coarse, humid-region soils to 4% in fine-textured, arid, or semiarid soils formed from high-Mg minerals.

K is essential for photosynthesis for the production and activity of specific ___ \_\_\_.

photosynthetic enzymes

Na in Plants: Na is essential for ___ plants that accumulate salts in vacuoles to maintain turgor and growth. Na⁺ concentration in ___ \_\_\_ varies from 0.01 to 10%. Many C4 plants require Na, which is specifically involved in water relations. Many C4 plants occur naturally in arid, semiarid, and tropical conditions.

halophytic leaf tissue

Name five porphyrin molecules Fe is used for in structural components.

1. cytochromes 2. hemes 3. hematin 4. Ferrichrome 5. leghemoglobin

The greatest world P resources are in ___ & \_\_\_.

Morocco & Western Sahara

A soil contains 2% OM with a 2% loss each year (SOM 58:5 C:N). The farmer wanted to increase OM to 3%. How many years will it take if she produces 10,000 lb crop residue/a (residue contains 44% C and 1% N and 70% of the residue is lost by oxidation /a/year). (Hint see page 144 Estimating Soil OM Production and SOM = 58% C, 5% N.)

\_\_\_ P: Available/exchangeable

Labile

Co is essential for the growth of some ___ \_\_\_. Plant concentration ranges from ___ to ___ ppm.

symbiotic microorganisms 0.02 to 0.5

\_\_\_ ___ generally contains low Mg, although, at rates applied to meet N or other macronutrient needs, sufficient Mg to meet most crop needs can be applied.

Organic biosolids

Cl^- is absorbed by plants through ___ and ___ . Active transport of Cl^- across ___ \_\_\_ occurs through other anion transporters.

roots and leaves plasma membranes

Soil OM: ___ forms stable complexes with high molecular-weight organic compounds (i.e., lignin, humic, and fulvic acids) that exist as soluble or insoluble complexes.

Zn⁺²

Soil solution Cu and plant available Cu are governed predominantly by solution pH and Cu adsorbed on clay and OM surfaces. Primary and secondary minerals dissolve to initially supply solution Cu, which is then adsorbed, incorporated into microorganisms, and complexed by soluble organic compounds.

True

Most of the K used for fertilizer comes from: A) mining K rich ores B) natural gas C) Western Sahara (Morocco) D) particulate deposits

A) mining K rich ores

A significant “pool” of organically complexed Cu in equilibrium with solution Cu contributes to ___ \_\_\_ to plant roots.

Cu⁺² diffusion

Interactions with Other Nutrients: ___ \_\_\_ can interact with Fe to induce Fe deficiency. (high Cu, Mn, P, induce low Fe)

Metal cations

Name four ways P ions are removed from the soil solution.

1) Precipitation reactions 2) Anion exchange reactions (outer sphere) – will be plant available 3) Reactions with Al or Fe oxide surfaces (inner-sphere) – fixation has taken place 4) Bond strength Ion

Ni is the latest nutrient to be established (in \_\_\_\_) as an essential nutrient to higher plants since the recognition of Cl- in 1954.

1987

Mainland ___ consumes the most P worldwide as of 2021

China

Organic Fe: Most animal wastes contain small quantities of \_\_\_-\_\_\_ Fe. The major benefit of an organic waste application is increased OM and associated ___ effects.

plant-available chelation

Plants take up P in the form of ___ & \_\_\_, sometimes as Soil organic phosphate as well. Mostly dependent upon pH of the soil will determine how P will be taken up.

H₂PO₄^‐ (Low pH) HPO₄^‐2(High pH)

Solution P is governed by the solubility of P minerals in the soil (Fig. 5.12). In acid soils Al and Fe phosphate minerals control solution P, while in neutral and calcareous soils Ca phosphate minerals are important. Availability of soluble phosphates is reduced by precipitation of insoluble Fe/Al or Ca phosphates.

True

Another K deficiency symptom is the ___ of stalks or stems, which causes ___ in small grains and stalk ___ in corn and sorghum.

weakening lodging breakage

P solution ___ in the presence of Fe, Al, Ca, K binding with P.

decreases

Mineral Zn content of the lithosphere is ≈ __ ppm, and Zn in soil ranges from 10 to 300 ppm (50 ppm average).

List five forms of Se present in soils.

1. Selenides 2. Elemental Se 3. Selenites 4. Selenates 5. Organic Se

Inorganic Cu: The most common source is CuSO₄. CuSO₄ is soluble in water and is compatible with most fertilizers. Soil and foliar applications are both effective, but soil applications are more common. Effectiveness is increased by thoroughly mixing Cu fertilizers into the root zone or by banding near the seed row.

True

If a plant residue contains 5000 kg N and 10 kg P, how many grams of H₂PO₄^- do you need to add to your soil to avoid net immobilization of P? (Hint: Assume C/P = 250 is taken as no net mineralization or immobilization)

5000 kg N/(10+X) kg P = 250 5000 = (250) (10+X) 5000 = 2500 + 250X 2500 = 250X **⸫ X = 10 kg P x (97/31) = 31.29**

Organic Zn: Most animal wastes contain small quantities of plant-available Zn, especially ranging from \_\_\_% to \_\_\_%. With large manure-application rates, sufficient plant-available Zn can be provided.

0.01% to 0.05%

\_\_\_ ___ is suspended phosphorus attached to particles that are filterable. A portion of this particulate P is also reactive orthophosphate and is typically analyzed along with the soluble orthophosphate.

Particulate phosphorus

The extent of inorganic ___ \_\_\_ depends on many factors, most importantly on soil pH

P fixation

Ni-deficient plants accumulate toxic levels of ___ in leaf tips because of reduced urease activity.

urea

Plant available Fe is governed primarily through ___ and ___ fractions in soils.

mineral and organic

S ___ is the conversion of organic S to inorganic SO₄^-2

mineralization

Ni has been demonstrated as essential to \_\_\_-\_\_\_ crops.

small-grain

Plants absorb Ca⁺² from the ___ \_\_\_, where mass flow and root interception are the primary mechanisms of Ca transport to the ___ \_\_\_.

soil solution root surface

Soil pH: Solution Cu ___ with ___ pH due to decreased mineral solubility and increased adsorption.

decreases with increasing

Soil Solution Cu: Solution Cu concentration is usually low, ranging between ___ and ___ M.

10^-6 and 10^-8

Soil Solution Zn⁺² is ___ (2-70 ppb), with more than half complexed by OM. Above pH 7.7, ZnOH⁺ becomes the most abundant species.

low

Exchangeable K on soil colloids is ___ \_\_\_.

readily available

P is active and mostly reactive that _______ to form compounds

phosphorylates

Soil solution K⁺ concentration optimum plant growth ranges from _ to __ ppm, depending on crop yield level.

1 to 10

\_\_\_ Ca can also be foliar applied to crops.

Chelated

What are the three abundant minerals that are not mineral?

1. C 2. O 3. H

Excess Mg occurs in soils formed from ___ \_\_\_ or influenced by ___ high in Mg.

serpentine minerals groundwaters

Because of the mobility of plant Mg⁺² and its ready translocation from ___ to ___ plant parts, deficiency symptoms often appear first on ___ leaves.

older to younger lower

\_\_\_ ___ \_\_\_(DIP): P desorbed from oxides or secondary minerals.

Dissolved inorganic P

K is essential for photosynthesis ___ \_\_\_ through leaf stomata

CO₂ absorption

K is part of many plant cell components such as proteins and chlorophyll.

False

K deficiency symptom for corn leaf is identical to N. The chlorosis that appears on older leaves makes it impossible to differentiate.

False

Adsorbed Cu: ___ is chemically adsorbed to surfaces of clays; OM; and Fe, Al, or Mn oxides.

Cu⁺²

Solute Concentration in \_\_\_: For plants to absorb and use nutrients efficiently, nutrients accumulate in ___ until transported to growing plant organs.

Vacuoles vacuoles

P content in biosolids ranges from 2 to 7%, with most present as ___ \_\_\_.

inorganic P

K in solution is \_\_\_

available

The eutrophication blamed on P in water bodies is highly exaggerated and scientifically false. Nitrogen is the cause of it all.

False

K is added to the soil solution by the ___ of ___ and cation exchange reactions as K⁺.

dissolution of minerals

Soil B exists in \_\_\_, adsorbed on ___ and Fe/Al ___ surfaces, combined with OM, and in soil solution.

minerals clay oxide

Organic B: B content in animal fertilizers ___ and may not provide ___ plant-available B to plants.

varies sufficient

\_\_\_ ___ is an important fraction is highly weathered, humid region soils containing large amounts of Al/Fe oxides.

Adsorbed SO₄^-2

The two dominant P species at normal soil pH are: A) H₂PO₄^-1 and PO₄^-3 B) H₃PO₄ and HPO4^-2 C) H₂PO₄^-1 and H₂PO₄^-2 D) H₃PO₄ and H₂PO₄^-1

C) H₂PO₄^-1 and H₂PO₄^-2

Name four nutrients in the soil that are immobile.

1. P 2. Fe⁺² 3. Zn⁺² 4. Mo

P mineralization from organic matter - (4‐10 lb/a/y) mineralized and plants need 10‐40 lb/a)

True

What are two methods of producing elemental Sulfur?

1. By-byproduct from H₂S gas 2. By traditional mining

Name three plant benefits Co has for plants.

(1) acid, highly leached, sandy soils with low total Co (2) highly calcareous soils (3) some peaty soils

Plants absorb Mn⁺² and ___ molecular weight organically complexed Mn.

low

Name 4 ways the soil solution is replenished?

1. Dissolution 2. Cation/Anion Exchange 3. Desorption 4. Organic Mineralization

\_\_\_ leaf color is also associated with P deficiency

Purple

\_\_\_, \_\_\_, \_\_\_, \_\_\_, ___ are the P forms in soil solution.

Adsorption, Absorption, Precipitation, Dissolution, Sorption

Name six symptoms Zn deficiencies that are widespread throughout the world and are identified.

1. light green, yellow, or white areas between leaf veins 2. eventual tissue necrosis in chlorotic leaf areas 3. shortening of stem or stalk internodes 4. small, narrow, thickened leaves 5. premature foliage loss 6. malformation of fruit, often with little or no yield

Diammonium phosphate (DAP) is produced by reacting 2 moles ___ with 1 mole of ___ \_\_\_.

ammonia phosphoric acid

B is one of the ___ widely applied micronutrients.

most

K is essential for photosynthesis for the maintenance of electroneutrality during ___ in \_\_\_.

photophosphorylation in chloroplasts

In addition to most inorganic Mg salts, other materials containing synthetic Mg chelates (2-4% Mg) and natural organic complexing substances (4-9%) are suited for application as foliar sprays.

True

Buffer capacity is the resistance to change, therefore Soil P in solution is buffered as well. These are all \_\_\_-\_\_\_

pH-dependent

P fertilizer may be ___ on the soil surface (liquid or dry) or it can be placed in a ___ \_\_\_.

broadcast concentrated band

Name 4 ways P mineralization occurs.

1) Conversion of organic P to inorganic P 2) Organic P -\> H₂PO₄^- 3) Precipitation 4) Adsorption

As a primary constituent of \_\_\_, Mg⁺² is essential for \_\_\_.

chlorophyll photosynthesis

If a soil has 2% OM content and mineralization rate is 1%, calculate the quantity of P mineralized (lb P/afs). Assume humus (OM) contains 58%C, 5% N and 0.5% P; C:N:P = 100:10:1

* OM is about 5% N, 0.5% P and only 1% OM is mineralized. * Total OM in an acre = 2x10⁶ x 0.02 = 40,000 lb OM * Total OM 1% mineralized 40,000 x 0.01 = 400 lb OM * 5% of mineralized OM is N = 400 x 0.05 = 20 lb N/a * 0.5% of mineralized OM is P = 400 x 0.005 = 2.0 lb P/a

Name five chemical inorganic sources of Cl.

1. Ammonium chloride (NH₄Cl) 2. Calcium chloride (CaCl₂) 3. Magnesium chloride (MgCl₂) 4. Potassium chloride (KCl) 5. Sodium chloride (NaCl)

Soil OM: Unavailable chelated Mn⁺² compounds form, causing low Mn⁺² availability in high-OM ___ and ___ soils.

peats and muck

Se in Plants: Se is not essential for plants, but it is required by animals. Plant species differ in Se uptake.

True

\_\_\_ in crops grown on coarse-textured soils are generally more susceptible to S deficiency because these soils often have low OM contents.

Immobilization

Animal and municipal wastes contain ~\_-\_% Ca by dry weight and are excellent Ca sources.

2-5%

P at High pH – fixation mostly as ___ \_\_\_

calcium phosphates

Too much P is not good due to environmental impacts such as ___ from surface water runoff

eutrophication

\_\_\_ (S₂O₃^‐2), which can also be absorbed by plants, requires less energy by the plant in ___ to S^‐2 and cysteine.

Thiosulfate conversion

Organic P exists as inositol P, phospholipids, nucleic acids, and other compounds.

True

Mg is required for the maximum activity of almost every ___ \_\_\_ involved in carbohydrate metabolism.

phosphorylating enzyme

In Mg-deficient acid soils, ___ \_\_\_ applications are recommended to increase soil pH and Mg availability.

dolomitic lime

P at low pH fixation is mainly by hydrous oxides of \_\_\_, \_\_\_, ___ and some chemical fixation by soluble \_\_\_, \_\_\_, \_\_\_.

Fe, Mn, Al Fe, Mn, Al

Under ___ soil moisture or in compacted soils, root growth is restricted, O₂ supply is reduced, and K absorption is \_\_\_.

high slowed

Calculate the percent of N, P and K, and N-P-K (=N-P₂O₅-K₂O) in the following fertilizer materials: NH₄NO₃, KCl, NH₄H₂PO₄, (NH₄)₂HPO₄, and CO(NH₂)₂ (Molecular weights, H = 1, K= 39, C = 12, N = 14, O = 16, P = 31, S = 32, Cl = 35.5, P = 39)

NH4NO3 %N = 28/80 x 100 = 35% %P = 0/80 x 100 = 0% %K = 0/80 x 100 = 0% N-P-K = 35-0-0 KCl %N = 0/74.5 x 100 = 0% %P = 0/74.5 x 100 = 0% %K = 39/74.5 x 100 = 52.35% K = %K x 1.2 = 52.35 x 1.2 = 63 N-P-K = 0-0-63 NH4H2PO4 %N = 14/115 x 100 = 12.17% %P = 31/115 x 100 = 26.96% %K = 0/115 x 100 = 0% P = %P x 2.29 = 26.96 x 2.29 = 62 N-P-K = 12-62-0 (NH4)2HPO4 %N = 14/132 x 100 = 10.61% %P = 31/132 x 100 = 23.48% %K = 0/132 x 100 = 0% P = %P x 2.29 = 23.48 x 2.29 = 54 N-P-K = 11-54-0 CO(NH2)2 %N = 28/60 x 100 = 46.67% %P = 0/60 x 100 = 0% %K = 0/60 x 100 = 0% N-P-K = 47-0-0

Plant Factors: Plant species and varieties differ in their susceptibility to Zn deficiency. \_\_\_, \_\_\_, and ___ \_\_\_ are susceptible to low Zn.

Corn, beans, and fruit trees

Soil Solution B: H₃BO₃0 I the predominant solution species over \_-\_ pH. B is transported in the soil solution to absorb plant roots by both ___ and ___ \_\_\_.

5-9 diffusion mass flow

Lignin Formation in Cell Walls: Several enzymes important to the synthesis of lignin contain Cu. Cu deficiency results in deformed ___ and \_\_\_, increasing the potential for lodging.

leaves and stems

P deficiency symptoms can appear in P-sensitive crops emerging under \_\_\_, ___ conditions, even in soils with sufficient plant-available P.

cool wet

The common B application methods are \_\_\_, \_\_\_\_, or applied as a ___ \_\_\_ or \_\_\_.

broadcast banded foliar spray dust

K is ___ in both soil and plants

mobile

Which of the following K fertilizer contains the highest K₂O%, relatively? A) K₂SO₄ B) KCl C) KNO₃ D) K₂CO₃

D) K₂CO₃

Muriate of potash is ___ (90% of all fertilizers)

KCl

There is no evidence of interactions among the micronutrients and with the secondary or major plant nutrients.

False

\_ ___ can influence the amount of K leached.

K source

A soil has a CEC = 10 meq/100 g with 40 and 2%, Ca and Mg saturation, respectively. Calculate the lbs/a of CaCO₃ and MgSO₄ needed to increase Ca and Mg saturation to 65 and 8%, respectively. (M.W. Ca=40, C=12, O=16, Mg=24, S=32).

Ca_increase = (10 meq/100 g) x (0.25) x (20 mg/meq) = 50 mg/100 g = 0.05 g/100g = 0.05 lb/100 lb = 0.05 lb x 20,000 = 1,000 lb/a CaCO₃ needed = (1,000 lb/a) x (100/40) = **2,500 lb/a** Mg_increase = (10 meq/100 g) x (0.06) x (12 mg/meq) = 7.2 mg/100 g = 0.0072 g/100g = 0.0072 lb/100 lb = 0.0072 lb x 20,000 = 144 lb/a MgSO₄ needed = 144 lb x (120/24) = **720 lb/a**

Cl^- is highly ___ in soils.

soluble

Continued ___ increases organic P mineralization decreasing soil organic P.

cultivation

Plant available Zn is governed predominantly by Zn mineral solubility, soil OM, and Zn adsorbed on clay and OM surfaces soils. Primary and secondary minerals initially dissolve to provide solution Zn, then adsorbed onto the CEC, incorporated into microbial biomass, or complex by organic compounds in solution. Like Fe, chelated Zn is essential to the transport of Zn to root surfaces for uptake.

True

%P₂O₅ = \_.\_\_ x %P %K₂O = \_.\_\_ x %K

%P₂O₅ = 2.27 x %P %K₂O = 1.20 x %K

Name six nutrients that are mobile in plants. Deficiency symptoms show up on ___ leaves first.

1. N 2. P 3. K 4. Mg 5. Cl 6. S older

Earth’s crust contains ≈ \_.\_% total Ca.

3.5

The ___ the proportion of high K minerals, the greater the potential K availability.

greater

O₂ and Photosynthesis: Most O₂ in the atmosphere originates from \_\_\_-\_\_\_ electrons in photosynthesis.

Mn-facilitated

\_\_\_ Ca⁺² uptake combined with ___ translocation of carbohydrates causes distinct symptoms in fruits and vegetable crops.

Low limited

Name two problems of excess Cl^- occur in some irrigated areas.

1. High Cl^- in the irrigation water 2. Insufficient water to leach accumulated Cl

\_\_\_\_ of the Cl^- uptake by high concentrations of NO₃^- and SO₄^-2 has been observed in many plants. The effect of Cl fertilization on ___ and ___ disease suppression has been observed on a few crops.

Depression root and leaf

Cl Functions: Cl^- is involved in ___ and ___ charge balance, which are important to biochemical processes.

osmotic and ion

What are the three fertilizer materials Ca is found in?

1. triple superphosphate (12-14% Ca) 2. calcium nitrate (19% Ca) 3. lime-ammonium nitrate (10% Ca)

The concentration of P in the soil solution is influenced by the rate and extent of P mineralization/immobilization, adsorption/desorption, and precipitation/dissolution reactions in the soil. Soils high in soluble Fe/Al react with ortho- and polyphosphates to form a variety of insoluble P compounds, depending on pH, which is largely unavailable to plants.

True

Low concentrations of V are beneficial for the growth of microorganisms, animals, and higher plants. Although essential for green algae, there is still no decisive evidence that V is necessary for higher plants. V may partially substitute for Mo in N₂ fixation by Rhizobia. It may also function in biological oxidation-reduction reactions. Increases in growth attributable to V have been reported for asparagus, rice, lettuce, barley, and corn. V requirement of plants is 62 ppb, whereas normal V concentration in plants averages approximately 1 ppm.

True

Soil solution Mg⁺² concentration typically ranges from _ to __ ppm in temperate region soils.

5 to 50

Photosynthesis and Respiration: Photosynthesis (reducing CO₂ to carbohydrates) and respiration (oxidizing carbohydrates to CO₂) involve the transfer of electrons that requires \_\_\_.

K is essential for photosynthesis for ___ \_\_\_. K provides much of the osmotic “pull” that draws water into plant roots.

water relations

What are the 3 main processes for Sulfur mining?

1. Open-pit mining 2. Underground mining 3. Frasch method

Inorganic Zn: __ \_\_ is the most common Zn fertilizer source. Inorganic Zn sources are satisfactory fertilizers because they are soluble in soils.

Zinc sulfate

K⁺ is absorbed by roots or immobilized by microorganisms or can be adsorbed to mineral surfaces or precipitate as secondary K compounds.

True

K is involved in the ___ of ___ important to energy utilization, starch synthesis, N metabolism, and respiration.

activation of enzymes

Interaction with Other Nutrients: Other metal cations ___ Zn⁺² uptake. This antagonistic effect is prevalent with Cu⁺² and Fe⁺².

inhibit

In ___ pH soils, elevated levels of exchangeable Al⁺³and Mn⁺² create an unfavorable root environment for nutrient uptake. More K⁺ can be adsorbed to CEC, reducing potential K leaching losses.

low

Soil Moisture: B deficiency is often associated with ___ weather, where low soil moisture reduces B release from OM and B uptake through ___ B ___ to absorbing root surfaces.

dry reduced transport

What are the 4 available soil solutions for K Gain?

1. Atmospheric deposition 2. Plant residues & Animal Manures 3. Inorganic fertilizers 4. Slowly available potassium minerals

What are the 8 Micronutrients?

1. Mn 2. Mo 3. Cl 4. B 5. Fe 6. Zn 7. Cu 8. Ni

Today most P fertilizer production is based on acidification of apatite from ___ \_\_\_.

phosphate rock

\_\_\_ P: Fixed/non-exchangeable P

Nonlabile

What are the 4 advantages of P banding?

1. Early crop growth enhancement 2. The concentration of P to minimize soil contact and reaction 3. Placement in the root zone 4. Minimize contact with Fe, Al, Ca, K which can precipitate

Primary K Minerals come from ___ and \_\_\_.

Feldspars and Mica

P manure is highly variable nutrient content and ranges between: N = XX - XX% P = XX-XX% K \> XX%

N = 25-90% P = 50-100% K \> 85%

The primary Ca sources are liming materials such as CaCO₃, CaMg(CO₃)₂, and others applied to neutralize soil acidity.

True

Name five free nutrients in the soil that are mobile.

1. NO₃^- 2. SO₄^-2 3. Ca⁺² 4. Mg⁺² 5. K⁺

P immobilization when C/P ratio \> XXX:1 (P \< 0.2%)

300

Organic Cl: Because of the solubility and mobility of Cl^-, most animal and municipal wastes are ___ in Cl^-.

low

What are the three Primary Macronutrients?

1. N 2. P 3. K

B fertilization rates depend on plant species, soil cultural practices, rainfall, liming, soil OM, and other factors.

True

Name five ways the soil solution nutrients are reduced.

1. Precipitation 2. Adsorption 3. Absorption 4. Sorption 5. Immobilization

Interactions with Other Nutrients: High Zn, Fe, and P concentrations in soil solution can ___ Cu adsorption by roots and ___ Cu deficiency.

depress intensify

Ca, Mg, and S are primary essential macronutrients, and they are all catalysts in plant metabolism.

False

List four items that Zn rates depend on.

1. the crop 2. Zn source 3. method of application 4. the severity of Zn deficiency

\_\_\_\_\_\_\_\_\_\_\_\_is the transfer of energy‐rich H₂PO₄^‐ molecules from ATP to energy‐requiring substances in the plant

Phosphorylation

\_\_\_ P: P left in the soil after fertilization

Residual

Mn and Lignin Synthesis: Like Cu, Mn activates several ___ that synthesize several amino acids and phenols important to ___ production.

enzymes lignin

Although it has been suggested that plants also absorb soluble, low-molecular-weight organic P compounds (i.e., nucleic acid and phytin), these P compounds are likely converted to H₂PO₄^‐in the \_\_\_.

rhizosphere

\_\_\_ ___ \_\_\_ (DRP) is a measure of the dissolved (soluble) phosphorus compounds that are readily available for use by plants and algae. Dissolved reactive phosphorus concentrations are an indication of a waterbody’s ability to support nuisance algal or plant growths (algal blooms).

Dissolved reactive phosphorus

P supply to plant roots is greatly enhanced by a ___ relationship between plant roots and fungal microorganisms called \_\_\_.

symbiotic mycorrhizae

Mg in clay minerals is ___ \_\_\_ by leaching and exhaustive cropping.

slowly depleted

Occluded and Coprecipitated Cu: A ___ fraction of soil Cu is occluded in various mineral structures, such as clay minerals and Fe, Al, and Mn oxides.

significant

Plants contain \_-\_% Mg⁺²

0.1-0.4%

\_\_\_ \_\_\_briefly increases with distance, peaks, and then decreases. pH decreases due to acidic solution.

Extractable P

Gains: fertilization, mineralization OM, desorption, particulate deposition, dissolution, weathering

True

Si in Plants: Plants absorb Si as silicic acid (H₄SiO₄0). Although no biochemical role for Si in plants has been identified, it has been proposed that enzyme-Si complexes form that act as protectors or regulators of photosynthesis and enzyme activity. The beneficial effects of Si have been attributed to partial remediation of toxic effects of high soil Mn⁺², Fe⁺², or Al⁺³; plant disease resistance; greater stalk strength and resistance to lodging; increased availability of P; reduced transpiration; and improved drought tolerance.

True

\_\_\_\_ P: P dissolved in extractants (Mehlich 1 or 3, Bray-P, Olsen, etc. (see Huluka and Evans, 1991)

Extractable

Name four ways fertilizers can correct ruminant Co deficiency.

1. adding it to feed, salt licks, or drinking water 2. direct injection 3. using Co bullets (oral tablets) 4. fertilizing forage crops with small amounts of C

Ca⁺² is essential for ___ \_\_\_ and \_\_\_; therefore, deficiency symptoms are primarily exhibited in ___ \_\_\_ of rapid cell division.

cell division and elongation meristematic regions

The main forms of Mo in soil include primary and secondary minerals, exchangeable Mo held by Fe/Al oxides, Mo in soil solution, and organically bound Mo. Although Mo is an anion in solution, the relationships between these forms are like those of other metal cations.

True

\_\_\_ ___ occurs when the potassium content of plants surpasses what is required for optimal growth.

Luxury consumption

Two soils have a CEC = 5 meq/100 g and a 25 meq/100 g. Calculate the exchangeable K content for both soils in lb/a.

Soil A (lb/a) = (5 meq/100 g) x (39 mg/meq) = 195 mg/100 g = 0.195g/100g = 0.195 lb x 20,000 = 3,900 lb K/a Soil B (lb/a) = (25 meq/100 g) x (39 mg/meq) = 975 mg/100 g = 0.975g/100g = 0.975 lb x 20,000 = 19,500 lb K/a

K is essential for photosynthesis for ___ of \_\_\_. Once CO₂ is assimilated into sugars during photosynthesis, they are transported from leaves to fruits, roots, tubers, and grains where they are stored or used for growth.

translocation of assimilates

Excessive amounts of Mo are \_\_\_, especially to grazing animals. High-Mo ___ may occur in wet, high-pH, and high OM soils.

toxic forage

Calcium, magnesium, and sulfur are taken up by plants as Ca^-2, Mg^-2, and SO₄⁺², respectively.

False

Organically Complexed B: OM represents a ___ potential source of plant-available B in soils, which ___ with increasing OM.

large increases

Organic S: There is a close relationship between organic C, total N, and total S n soils. The C:N:S ratio in most well-drained, noncalcareous soils is about \_\_\_.

120:10:1.4

Plant roots absorb \_\_\_, which is involved in many enzymatic activities.

Zn⁺²

\_\_\_‐\_\_\_ fertilizer or ___ P applied to soil increases P in soil solution

Water-soluble biosolid

S cycle, forms, gains, and losses in soil are similar to which of the following essential nutrient comparatively? A) N B) K C) Mg D) P

A) N

Cell Turgor: For rapid gas exchange by leaves during active photosynthesis, the epidural guard cells of stomates are turgid, caused by ___ \_\_\_ from neighboring cells.

K⁺ pumped

Soil pH: MoO₄^-2 availability, unlike that of other micro-nutrients increases approximately ___ per unit increase in soil pH.

tenfold

Plant essential micronutrients are needed in such very small amounts and thus they do not cause any chlorosis when deficient and no toxicity when too much in soil.

False

Inorganic Mn: Manganese sulfate is the most common Mn source and is soil or foliar applied. Natural organic complexes and chelated Mn are also available and are usually foliar applied. Broadcast application of Mn chelates, and natural organic complexes is not normally advised because soil Ca or Fe can replace Mn in these chelates, and the freed Mn is usually converted to unavailable forms. Also, more available chelated Ca or Fe enhance Mn deficiency.

True

B is ___ needed by animals, fungi, or microorganisms. Its primary function is in the plant ___ \_\_\_ \_\_\_.

not cell wall structure

\_\_\_ ___ represents the entrapment of K⁺ between the layers of 2:1 clays, predominantly ___ \_\_\_.

K fixation hydrous mica

Chelate Dynamics: Numerous soluble organic compounds in the soil can complex, or chelate, \_\_\_, and other micronutrients.

Fe⁺³

Name three sources of Na-containing fertilizers.

1. K fertilizers with NaCl impurities 2. NaNO₃ (~25% Na) 3. Multiple nutrient fertilizers with Na

Mn Deficiency and Toxicity: Because of its essential role in photosynthesis, root and shoot growth rates are reduced in Mn deficient plants. As a result, N and P accumulate, which increases the potential for root and leaf diseases. Mn is immobile in the plant, so ___ leaves initially exhibit deficiency symptoms.

younger

Cl concentration is \_\_\_% to \_\_\_% in Earth’s crust and occurs primarily in igneous and metamorphic rocks.

0.02% to 0.05%

Ca deficiency is uncommon but can occur in highly \_\_\_, ___ acid soils.

leached, un-limed

Soil contains 2% soil organic matter (SOM) with an annual decomposition rate of 1%. Calculate the amount of N and P mineralized (lb/afs) from SOM (Assume humus SOM = 58% C, 5% N and 0.5% P)?

Total OM in an acre = 2x10⁶ x 0.02 = 40,000 lb OM Total OM 1% mineralized = 40,000 x 0.01 = 400 lb OM N mineralized = 400 lb OM x 0.05 = 20 lb N/afs P mineralized = 400 lb OM x 0.005 = 2.0 lb P/afs

Reduced Inorganic S (S^-2 and S^o): Sulfides do not exist in well-aerated soils. In normal submerged soils well supplied with Fe, the H₂S liberated from OM is almost completely removed from the solution by reaction with Fe⁺² to form FeS, which undergoes conversion to pyrite (FeS₂).

True

Soil OM: Higher B availability in ___ soils compared with subsurface soils is related to increased soil OM.

surface

The majority of Cl^- in soils originates from ___ trapped in parent material, from marine \_\_\_, and from volcanic \_\_\_.

salts aerosols emissions

Organic Mo - Only small quantities of Mo occur in ___ wastes (0.0001–0.0005% Mo), although with most manures, average application rates will provide sufficient plant-available Mo. Mo content in ___ waste is usually low, averaging 0.0001% Mo.

animal municipal

Adequate ___ is associated with increased root growth

Mg⁺² is absorbed by plants from the ___ \_\_\_ and, like Ca⁺², is supplied to plant roots predominantly by ___ \_\_\_.

soil solution mass flow

P mobility in soil is ____ or \_\_\_\_

little or none

K in organic wastes (manure and sewage sludge) occurs predominantly as ___ \_\_\_K⁺.

soluble inorganic

Soil Aeration - Normal root function is strongly dependent on an adequate ___ supply.

O₂

Interaction with Other Nutrients: ___ levels of Cu, Fe, or Zn can reduce Mn⁺² ___ by plants.

High uptake

The equilibrium among solution, exchangeable, organic, and mineral forms determines Mn availability to plants. The major processes are Mn oxidation-reduction and complexing solution Mn with natural organic chelates. Like Fe, the continuous cycling of OM significantly contributes to soluble Mn. Factors influencing the solubility of soil Mn include pH, redox, and organic complexation. Soil moisture, aeration, and microbial activity influence redox, while complexation is affected by OM and microbial activity.

True

Mineral Cu: Cu concentration in Earth’s crust averages about \_\_-\_\_ ppm.

50-70

Dissolved P needs to stay below 0.03 mg/L to avoid eutrophication issues (waterway and oceanic).

True

The relative mobility of B in plants ___ among species.

varies

%K₂O = %K x \_.\_\_

1.20

Solution Mo: The extremely low concentration of solution Mo is reflected in the low Mo content of ___ material. At solution concentrations 74 ppb, Mo is transported to plant roots by ___ \_\_\_, while Mo diffusion to plant roots occurs at levels 64 ppb.

plant mass flow

Name 5 out of 9 P fertilizer sources.

1. Triple super phosphate (TSP) -\> 0‐44‐0 2. Diammonium phosphate – DAP -\> 3. Monoammonium phosphate – MAP -\> 4. Ammonium polyphosphate (APP) 5. Monopotassium phosphate (KH₂PO₄) -\> 0‐51‐35 6. Dipotassium phosphate (K₂HPO₄) -\> 0‐41‐41 7. Rock phosphate – not a soluble source of P -\> 8. Bone Meal – organic, ~ 9% P₂O₅ 9. Struvite (and closely related Brushite) – mineral from sewage sludge processing, also has Mg

Mineral B: B occurs in low concentrations in Earth’s ___ and in most ___ rocks. Total B in soils varies between __ and __ ppm. The main B mineral in soils is \_\_\_, relatively insoluble borosilicate.

crust igneous 2 and 200 tourmaline

Weathering of mica to vermiculite in clay minerals: * K Content = ~10% Mica, CEC = 0 * K Content = 6-8% & 4-6% Hydrous Mica, CEC = 30-50 * K Content = \<1% Vermiculite, CEC = 150

True

In cruciferous S-deficiency crops, it may develop as a reddish color on the undersides of the leaves, turning redder as it progresses and resulting in paler-than-normal blossoms and severely impaired seed set.

True

The ___ \_\_\_ treatment process of bones and P minerals (apatite) was patented in the mid-1800s.

sulfuric acid

B-deficiency symptoms vary with crop species but commonly affect both ___ and ___ \_\_\_.

root top growth

S cycling in the soil-plant-atmosphere continuum is similar to N since both have ___ components, inorganic and organic. Their occurrence in soils is mainly associated with \_\_\_.

gaseous OM

Si in Soils: Si is the second most abundant element in Earth’s crust, averaging ≈ \_\_\_Si, while Si content in soils is 5% to 40%.

28%

Plant Factors: Although ___ of both Fe⁺³ and Fe⁺² to the root occurs, Fe⁺³ is reduced to Fe⁺² before \_\_\_. Some plants exhibit a unique mechanism to tolerate low Fe availability.

diffusion absorption

The most essential function of P in plants is in ____ \_\_\_\_ and transfer ___ and \_\_\_.

energy storage ATP ADP

The quantity of P mineralized in soils ___ with increasing organic P content

increases

O₂ and Photosynthesis: ___ is important Mn function in the photosynthetic production of carbohydrates from CO₂ and the evolution of O₂.

Cl^-

Plant factors: Crops vary in their sensitivity to ___ solution Mo

low

Interactions with Other elements: When ___ availability is high, plants can tolerate ___ B availability. Under ___ Ca supply, many crops exhibit ___ B tolerance.

Ca higher low lower

Weather Effects: Under dry soil conditions Mn availability is \_\_\_. In saturated soils, soluble Mn⁺² can increase to ___ levels.

reduced excessive

Mo is absorbed as the weak acid ___ that can form complexes with other anions such as phosphomolybdate. Mo ___ may explain why Mo can be absorbed in relatively large amounts without any apparent toxicity. Mo content of plants is normally low (\_\_\_ - ___ ppm), because of extremely low MoO₄^-2 in solution.

molybdate complexation 0.2–2

\_\_\_ can block K in the clay interlayers (non-expanding clays).

NH₄

Which of the following fertilizer contains the highest percentage of sulfur? A) K₂SO₄ B) H₂SO₄ C) (NH₄)₂SO₄ D) S

D) S

B adsorbed by plants is predominantly undissociated ___ \_\_\_. The anion forms exist when soil pH \> \_.

boric acid 7

\_\_\_ ___ is the most common B source.

Sodium tetraborate

\_ is the most absorbed by plants except N.

\_\_\_ cycling in soils is very similar to that described for Fe and Zn.

Nonexchangeable K in Secondary minerals is ___ \_\_\_

slowly available

K ___ is a slow process compared with the mass flow and is limited to distances of only 1-4 mm. ___ accounts for approximately \_\_% of K absorption by roots

diffusion Diffusion 90

In most soils, K ___ \_\_\_ are small, except in coarse‐textured or organic soils in humid regions or under irrigation.

leaching losses

Peak Phosphorus is predicted to occur in 20XX-20XX, non-renewable and finite resource.

2040-2050

Organic Cu: Although most animal wastes contain small quantities of plant-available Cu, elevated Cu levels occur in swine manure because of Cu added to the feed. As with Fe and Zn, the primary benefit of an organic waste application is increased OM and associated natural chelation properties that increase Cu availability.

True

\_\_\_ is the process or technique of treating a material with acid. Treating phosphate rock with acid is a good example of \_\_\_.

Acidulation acidulation

Continued application of wastes based on crop N requirements will substantially ___ soil P.

increase

Good correlations have been obtained relating P taken up by plants and chemical soil tests.

True

Ni content of plants normally ranges from 0.1 to 1.0 ppm and is supplied to plants as \_\_\_.

Ni⁺²

Climatic Conditions: Zn deficiencies are more pronounced during \_\_\_, ___ seasons and often disappear during warmer weather.

cool, wet

Zn Adsorption: The mechanism of Zn⁺³ adsorption does not occur to any great extent on the ___ compared to Ca⁺² and Mg⁺².

CEC

Which of the following is a beneficial but not an essential plant nutrient? A) Ni B) Cl C) Se D) Al

C) Se

Plant-growth limiting deficiencies are generally rare in areas of significant atmospheric ___ - \_\_\_.

Cl-deposition

Na in Soils: Na content in Earth’s crust is about \_\_\_%, while soils contain 0.1-1%. Low Na in soils indicates weathering of Na from Na-containing minerals. Soil solutions contain between 0.5 and 5 ppm Na⁺ in temperate regions.

2.8%

Early sources of phosphate fertilizer were mostly animal-based \_\_\_, \_\_\_, \_\_\_.

bones, guano, manure

In addition to the cell wall structure, B is essential for the normal ___ of water, nutrients, and photosynthetic sugars too rapidly developing ___ such as root tips, leaves, buds, and storage tissues.

transport tissues

Mineral Fe is the ___ most abundant element, comprising about \_% of Earth’s crust.

fourth 5

Fe/Al Oxides: Mo is strongly adsorbed to Fe/Al ___ \_\_\_.

oxide surfaces

Adsorbed B: B adsorption and desorption can ___ solution B, which ___ B leaching potential. It is a major form of B in \_\_\_, high-B soils.

buffer reduces alkaline

Mn⁺² moves to the root surface by ___ of chelated Mn⁺², like Fe. Solution Mn⁺² is ___ under low pH and low O₂ conditions.

diffusion increased

Ca⁺² is essential for the ___ of carbohydrates and nutrients.

translocation

Soil pH and Bicarbonate: Fe deficiency is most often observed on \_\_\_-pH and ___ soils in ___ regions, but it can occur in acid soils low in total Fe.

high-pH calcareous arid

Application of \_\_\_may result in elevated levels of Ni in crop plants. Plant ___ have recently been identified from wild mustard, Thlaspi goesingense, which enable plants to accumulate high levels of Ni.

biosolids genes

When released through weathering of primary rocks, Mn will combine with O₂ to form ___ \_\_\_.

secondary minerals

P mineralization occurs when C/P \< XXX:1 (P\>0.3%)

200

Soil pH: B availability ___ with increasing soil pH, especially at pH \> 6.5. Liming acid soils can cause a ___ B deficiency in susceptible plants.

decreases temporary

Initial ___ \_\_\_ appears as light green leaves, ultimately turning yellow.

S deficiency

\_\_\_ and ___ \_\_ fractions buffer the increase in solution P through P adsorption on mineral surfaces, precipitation as secondary P minerals, and immobilization as microbial or organic.

Inorganic organic P

How many lbs of KCl (muriate of potash, 60% K₂O) is needed to increase a 0.1 meq K⁺/100 g soil to 0.3 meq/100 g soil? (Assume molecular weight K=39, O=16, Cl=35.5 and 1 acre = 2 million lbs.)

K_increase = (0.2 meq/100 soil) x (39 mg K/meq) = 7.8 mg K/100 g = 0.078 g K/100 g = 0.078 lb K x 20,000 = 1,560 lb K/a KCl needed = 1,560 lb K/a x (39 + 35.5)/39 = **2,980 lb/a**

P mobility in plants is \_\_\_\_\_

mobile

Soil pH: Zn⁺² availability ___ with ___ soil pH.

decreases increasing

There are eight plant essential micronutrients, five are taken up as anions, and three as cations.

False

Accumulation of ___ leaves under Ca⁺² stress decreases ___ content of stems and roots, which impairs normal ___ function.

carbohydrate carbohydrate root

B fertilizers should be uniformly soil-applied because of the ___ range between ___ and \_\_\_.

narrow deficiency and toxicity

Soil Solution Fe: Compared with other cations, the solubility of common Fe minerals in the soil is very low depending on pH. For each pH unit increase, Fe⁺³ concentration decreases a thousandfold. And, Fe⁺² decreases a hundredfold for each unit increase in pH.

True

What are five genotype differences relating to crops sensitivity to Cu?

1) differences in Cu absorption rates 2) greater soil exploration 3) increased Cu solubility 4) more efficient Cu transport from roots to shoots 5) lower Cu requirement

Photosynthesis is CO₂ assimilation therefore if _ is increased then respiration increases as well.

P Loss: fixation by soil oxides, plant uptake, adsorption, immobilization, precipitation, leaching, runoff, erosion, etc

True

The original source of soil S is ___ \_\_\_ minerals that ___ during weathering from S^-2 to SO₄^-2.

metal sulfide oxidize

Carbohydrate and Lipid Metabolism: If photosynthesis is impeded by ___ deficiency during the vegetative growth stage, then carbohydrate production and plant growth are reduced.

Nearly all chloride (Cl^-) in soils exists in ___ \_\_\_.

soil solution

Organic Mn: Mn concentration in most animal wastes is like Zn, ranging from __ to \_\_%Mn. Average application rates of most manures will provide sufficient plant-available Mn. As with Fe, Zn, and Cu, the primary benefit of an organic waste application is increased OM and associated natural chelation properties increasing Mn availability.

0.01 to 0.05%

A soil contains 2% OM with a 2% loss each year (8:1 N:S). A clover crop grown on this soil yields 10,000 lbs/a (N:S = 12:1, 3% N content). 1. Calculate the amount of S mineralized each year (lbs/a) 2. Is the mineralized S enough for S needed? 3. How many lbs/a of CaSO₄.2H2O would be required if S mineralized in (b) is not enough?

1. Calculate the amount of S mineralized each year (lbs/a) Total OM in an acre = 2x10⁶ x 0.02 = 40,000 lb OM Total OM 2% Mineralized = 40,000 x 0.02 = 800 lb OM N mineralized = 800 lb OM x 0.05 = 40 lb N/afs S mineralized = 40 lb N/afs / 8 = **5.0 lb S/afs** 1. Is the mineralized S enough for S needed? S needed = ((10,000 lbs/a) x 0.03) / 12 = **25 lb S/afs** S needed is greater than S mineralized therefore addition S will be required. 1. How many lbs/a of CaSO₄.2H₂O would be required if S mineralized in (b) is not enough? S required = 25 – 5.0 = **20.0 lb S/afs**

Fe toxicities commonly occur in plants grown on ___ and/or ___ drained soils.

acid poorly

The stability of phosphate enables it to participate in the numerous energy capture, transfer, and recovery reactions that are vital for plant growth.

True

Foliar B application is practiced for ___ tree fruit crops, often combined with pesticides.

perennial

Flooding: When soils are submerged, the concentration of many nutrients increases, but not \_\_\_.

K is essential for photosynthesis through ___ synthesis.

ATP

Estimate the annual excess P applied with 3 t/a swine waste (2%N; 1.5%P), where crop yield is 3 t/a (0.3% P).

Excess P = Applied – Crop Yield Removed = (3 t/a x 0.015) – (3 t/a x 0.003) = 0.036 P t/a

\_\_\_ and ___ are closely associated with animal nutrition and are essential for energy transfer and utilization.

P and Ca

Inorganic Mo - Mo fertilizers are generally applied at ___ rates (0.03–1 lb/a), depending on the application method. Mo solutions are soil or ___ applied or applied as a seed coating. Seeds treated with a solution of ___ molybdate are widely used because of the low application rates needed. To obtain the satisfactory distribution of the small quantities of Mo applied to soil, Mo sources are sometimes combined with ___ fertilizers. Foliar spray applications with NH₄^- or Na-molybdate are also effective in correcting \_\_\_.

low foliar Na N-P-K deficiencies

Mineral Mn: Mn concentration in Earth’s crust averages ≈ ___ ppm, and Mn is found in most Fe-Mg rocks.

1000

\_ ___ increases crop damage by bacterial and fungal diseases, insect and mite infestation, and nematode and virus infection.

K stress

With increasing P deficiency, the dark green color changes from a \_\_\_-\_\_\_ to \_\_\_-\_\_\_.

greyish green bluish-green

While Ca⁺² is important for \_\_\_, Ca⁺² is generally ___ in the plant.

translocation immobile

Inorganic Fe: Fe ___ is one of the most difficult micronutrient deficiencies to correct in the field. Fe deficiencies are corrected mainly ___ application of inorganic Fe.

chlorosis foliar

Monoammonium phosphate (MAP) is produced by reacting 1-mole ___ with 1 mole of ___ \_\_\_.

ammonia phosphoric acid

Rock phosphate is mined for P fertilizer and this resource will last for millions of years even if its current use is increased many folds.

False

Fe is absorbed by roots as ___ or \_\_\_.

Fe⁺² or Fe⁺³

Cl^- Deficiency and Toxicity Symptoms: Chlorosis in ___ leaves and an overall wilting of plants are the most common symptoms.

younger

Which of the following does not contribute to soil solution K? A) K fixation by 2:1 minerals B) adding K containing fertilizers to soil C) K desorption from exchangeable K D) mica dissolution

A) K fixation by 2:1 minerals

\_\_\_ ___ is characterized by a reduced plant growth rate, where plants are stunted, thin-stemmed, and chlorotic.

S deficiency

K is not a component of ___ \_\_\_ in plants.

biochemical compounds

Solution SO₄^-2 is transported to roots by ___ \_\_\_ and ___ and can be leached through the soil profile.

mass flow and diffusion

\_ ___ generally increases with increasing OM content.

S availability

List three primary sources of Si fertilizers.

1. Calcium silicate slag (CaAl₂Si₂O₈) 18-21% Si 2. Calcium metasilicate (CaSiO₃) 31% Si 3. Sodium Metasilicate (NaSiO₃) 23% S

\_\_\_\_ is an essential element in DNA and RNA that contain the genetic code of the plant

Soil Moisture and Temperature - With low soil moisture, water films around soil particles are thinner and discontinuous, resulting in a more tortuous path for K⁺ diffusion to roots. Increasing K levels or soil moisture content increases K diffusion.

True

Total Mn in soils is between ___ and ___ ppm, averaging about ___ ppm. Mn in soils occurs as various oxides and hydroxides coated on soil particles, deposited in cracks and veins, and mixed with Fe oxides and other soil conditions.

20 and 3,000 600

Small quantities of SO₂ can be absorbed through plant ___ and utilized by plants.

leaves

Section 2 - Essential Plant Nutrients Flashcards

(340 cards)