soil test 2
Magnesium deficiency symptoms occur first in older plant leave T or F?
true
Phosphhorus plays an important role in the plant processes of photosynthesis and respiration T or F?
true
Since potassium is considered an immobile nutrient in most soils, is should be incorporated whenever possible for most crops T or F?
true
Plants take up K by (passive or active) uptake.
• Active uptake (K+)
. What are the two sources of K loss from the soil?
• Leaching (sandy soils) • Crop removal
For the two most common K fertilizers, answer the following: a. names
• Muriate of potassium or potassium chloride • Sul-Po-Mag or K-Mag (Potassium-magnesium Sulfate)
What are the effects of K on plants?
•Drought resistance (helps regulate the stomata) •Reduced lodging •Disease resistance •Improves crop quality
Describe the functions of K in a plant
•Enzymatic reactions (ATP & ADP). •Protein synthesis. •Photosynthesis. •Carbohydrate metabolism. •Translocation of food. •K remains in sap and is not part of a structural component
Describe the K deficiency symptoms in plants.
•Mobile in the plant (N, P & K) •Shows up in older leaves first because nutrients is moved to newer leaves •Crop symptoms-firing starts on edge of the leaves then moves in
Describe the functions of P in a plant.
-Energy storage & transfer (ATP) -Respiration. -Photosynthesis. -Cell division & growth. -Transfer of genetic information (RNA & DNA).
What are the effects of P on plants?
-Root development. -Early spring growth & seedling vigor. -Tillering of small grains & grasses. -Resistance to drought ( WUE) & cold temps. -Hastens maturity & grain dry down. -Increases yield.
. Name and describe the factors affecting P availability
-Type & amount of clay. -Timing & method of application. -Aeration. -Compaction. -Moisture. -Temp. -Phosphate status in soil. -Other nutrients. -Soil pH. -Crop grown.
What three properties of anhydrous ammonia causes damage to living organisms?
1. At the point of the knife, the temperature will be -28F freezing everything that contacts itj 2. The pH is high (9.5-10) for a short period in the injection zone resulting in a toxic condition 3. The affinity of NH3 for water draws water from living cells, killing them
Name the five sources of sulfate for plants. Which one is the most important source?
1. Soil organic matter-most important 2. Manure 3. Atmospheric Sulfur 4. Sulfate in water 5. Subsoil Sulfur
Review the factors affecting P availability on pp. 5-4 & 5-5.
1. Type of clay 2. Amount of clay 3. Time and Method of application 4. Aeration 5. Compaction 6. Moisture 7. Temperature 8. Phosphate Status of soil 9. Other nutrients 1o. Soil pH
Ammonium polyphosphate
10-34-0
Maximum total salt content in a 2 x 2 band is _____ lbs/A for corn & ______ lbs/A for soybeans.
100 corn 70 for soybeans
What is the optimum critical N:S ratio for legumes
11:1
Recommended knife spacing for anhydrous ammonia application for winter wheat?
12-18''
What is the optimum critical N:S ratio for non legume
15:1
what is 2x2 placement
2 in below and 2 in to the side of the seed
Most crops receive less than ______% of fertilizer P during the first year following application.
30
Recommended knife spacing for anhydrous ammonia application for corn
30-40''
Depth of application in the spring for anhydrous ammonia is a minimum of what for small grains
5''
Review advantages and disadvantages of broadcasting and banding of phosphorus fertilizer.
5-7
Phosphorus generally would be most available to plants with a pH of?
6.5
Depth of application in the spring for anhydrous ammonia is a minimum of what for row crops
7"
In plants magnesium is?
A component of chlorophyll molecule Involved in phosphorus metabolism Part of the plant enzyme systems
Why are sulfur deficiencies more common than they used to be?
Air pollution regulations have become stricter which means less atmospheric sulfur
. What are two common fertilizer sources of sulfur?
Ammonium thiosulfate (12-0-0-26S) Elemental sulfur (90%)
What form is calcium taken up by plants?
Ca++
Know the forms of calcium fertilizers and recognize the chemical formulas.
Calcite (CaCO3) Dolomite (CaCO3+MgCO3) Gypsum (CaSO4
Describe the methods of potassium fertilizer application.
Can either be broadcast or banded near the seed. it is an immobile nutrient and should be incorporated for most crops. However topdressing is effective on perennial crops
The most important source of potash for the U.S. comes from what region?
Canada In US Newmexico and utah
DAP
Diammonium Phosphate 18-46-0
How does P move to plant roots?
Diffusion
P & K primarily move to plant roots by (diffusion, mass flow or root interception).
Diffusion
What two forms of P do plants take up (be familiar with the names, symbols and associated pHs)?
Dihydrogen phosphate or primary orthophosphate (acid) → H2PO4- (-1 charge) Monohydrogen phosphate or secondary orthophosphate (alkaline) → HPO4 -2 (-2 charge)
How can dry weather induce potassium deficiency?
Dry weather droughty conditions `looks like K deficiency as well
What are the three sources of P loss from the soil?
Erosion Surface runoff Crop removal
Ammonium thiosulfate is an excellent choice for a pop-up fertilizer placed with the seed because it contains N as well as S. T or F
False
An important result of banding phosphorus applications is to reduce soil-to-phosphorus contact thus increasing the rate of fixation to less soluble phosphate forms T or F?
False
Most nitrogen fertilizer comes from the synthetic fixation of atmospheric nitrogen using UAN as a base product. T or F?
False
A non-nutrient use of sulfur would include its foliar application as a ____ in several crops
Fungicide
Describe the sulfur deficiency symptoms in plants (what other nutrient deficiency do this symptoms appear like).
General yellowimg and stunting and are offten difficult to differentiate from other plant problems -Begin on young leaves while Mistaken for N Deficiency
Phosphorus losses from the soil by erosion are ___ losses from leaching
Greater than
Describe the calcium deficiency symptoms in plants.
Growing points of both tops & roots. Immobile in plant. Acid soils. Field deficiencies are rare --> high soil acidity limits growth first
Describe the functions of magnesium in a plant.
Heart of chlorophyll. Involved in photosynthesis. Aids in phosphate metabolism. Activates several enzyme systems.
What is not an advantage of anhydrous ammonia as a nitrogen fertilizer
Ideal application via sprinkler irrigation
Inorganic Phosphorus
Inorganic (P fixation) reaction with elements that makes the nutrients unavailable
Rock phosphate was one of the earliest P fertilizers but is no longer widely used. Why?
It has low availability to plants
How do you convert potash to elemental potassium and vice versa?
K = K2O x 0.83 K2O = K x 1.2
SUL-PO-MAG is an excellent fertilizer source of
K, S, Mg
The analysis of potassium fertilizer, as displayed on a fertilizer bag is reported as percenatge of?
K2O
Potassium content is expressed in what form (name and symbol) in fertilizers?
K2O (potash)
chemical formula , % potash, form (dry or fluid) of Sul-Po-Mag or K-Mag (Potassium-magnesium Sulfate)
K2SO4 . 2MgSO4 22% K20, 11% Mg and 22% S
chemical formula , % potash, form (dry or fluid) of Muriate of potassium or potassium chloride
KCl 60-63% K2O and 45% chloride dry
In comparing ammonium nitrate fertilert to urea, ammonium nitrate is _______ than urea
Less subject to volatillization losses
Salt injury to seed or seedlings from phosporus banded in the row is ____ from nitrogen or potatssium banded at the same rate
Less than
What substances in the soil cause P fixation at acid and alkaline pHs?
Low pH--> Al and Fe High pH-->Ca
(MAP or DAP) may be used safely applied in direct seed contact without causing germination damage.
MAP
Three most common sources of phos
MAP-dry DAP-dry Ammonium polyphosphate-liquid
Dolomitic lime is an economical source of _____ for use on acid soils
Mg
The livestock disease of grass tetany may result from a deficiency of _____ in forage used for feed.
Mg
Map
Monoammonium phosphate 11-52-0
What two primary nutrients are considered when determining a fertilizer's salt index.
N and K2O (potassium oxide)
Organic phosphorus
Organic (plant residues and manure)-broken down with mineralization (conversion of organic to inorganic)
How do you convert phosphate to elemental phosphorus and vice versa?
P = P2O5 x 0.44 P2O5 = P x 2.29hn
Which equations correctly expresses the conversion of phosphate (P2O5) to elementat phosphorus (p)?
P=P2O5 x 0.44
Phosphorus content is expressed in what form (name and symbol) in fertilizers?
Phosphate P2O5
On a bag of commercial fertilizer, all of the phosphorus content indicated by the fertilzer grade is __ phosphorus
Plant-available
Which of the following is the preferred potassium fertilizer for tobacco and other chloride-intolerant crops
Potassium sulfate
Describe the functions of calcium in a plant.
Promotes root formation, leaf development and root nodulation. Inside the plant it forms calcium pectate that gives strength to cell walls
Describe the P deficiency symptoms in plants.
Purpling or browning • Respiration decreases before photosynthesis slows sugars accumulate • Sugars used to make anthocyanin (purple pigment). -Stunting. -Poor tillering in small grains & grasses. -Dead areas on leaves, stems & fruit. -Nothing visual on some crops. -Reduced yield.
Fixation refers to the process by which phosphorus is?
Retained in a less soluble form by the soil
What is the raw material from which most of the phosphorus fertilizers are produced?
Rock phosphate
_____ is not a phosphorus deficiency symptom in crops?
Rosetting of upper leaves Reduced tillering of small grains, Abnormal coloration, and delayed maturity are deficiency conditions
a. Elemental sulfur is unavailable to plants until what happens?
S is unavailable to plants until converted by soil bacteria into sulfate
What symptoms would be seen on the seedling roots as a result of this "burn."
Seedling roots may look brown or burned and seedlings will appear wilted
Soils in the Great Plains are high in K compared to the eastern states. Why?
Soils in the great plains have been subjected to less precipitation and weathering than in the more humid eastern states.
What is the name and chemical symbol of the form of sulfur taken up by plants?
Sulfate (SO4)
Describe the functions of sulfur in a plant.
Sulfur is needed for seed production, oil in oil seed crops and nodulation in legumes -Activates vitamins & enzyme systems (nitrate reductase).
Fall application of anhydrous ammonia should be delayed until the soil temperature is below 50 F. Why?
The potential for denitrification, leaching and other losses. nitrate forms are more subject to loss
What substance gives potassium a red color?
The red color is caused by iron in the KCI
Proper application depth is the single most important way to avoid seedling toxicity from anhydrous ammonia. T or F?
True
Volatilization loss from surface-applied urea is of most concern under which two conditions?
Warm temperatures and heavy surface crop residues
______ is a benefit of an adequate soil phosphorus level on crops?
a. Encourages root development b. Improves resistance to drought and cold stress c. Hastens maturity d. none of the above D
b. What four factors will increase the availability of sulfate to plants from elemental sulfur?
a. Warm temperature b. Adequate soil moisture c. Good aeration d. Fine-sized particles of S ground to pass an 80-100 mesh screen
Plants take up P by (passive or active) uptake
active uptake.
What is another name for rock phosphate
apatite
Explain what happens when seedling roots experience "burn."
dehydration of the seedling roots.
How does K move to plant roots?
diffusion
Most of the cost of manufacturing anhydrous ammonia is due to the expense of the (hydrogen or nitrogen) source?
hydrogen
Which of the following statements relative to calcium as a plant nutrient element is not correct?
is a constituent of chlorophyll
Why doesn't calcium leach from the soil?
it is immobile and occupies 70-90% of the soils CEC
What % of the nitrogen fertilizers sold in the U.S. today is organic?
less than .5 %
Fertilizer placed in direct contact with the seed is also referred to as a _______________ placement.
pop up placement
What is the most common type of potassium fertilizer?
potash
Rank the following crops from most to least tolerant of seed-placed fertilizer: grain sorghum, corn, small grains and soybean.
small grains, corn, sorghum, soybean
