MANAGEMENT EXAM 2025/2026 WITH
ACTUAL CORRECT QUESTIONS AND
VERIFIED DETAILED ANSWERS
|FREQUENTLY TESTED QUESTIONS AND
SOLUTIONS|ALREADY GRADED A+| BRAND
NEW VERSION!!|GUARANTEED PASS
How is remote sensing used to asses plant nutrient status?
sensors carried by aircraft or satellites are used to measure specific plant spectral properties at
a specific location. a previously found relationship between nutrient status and these plant
properties is then used to assess nutrient status spatially or temporally.
How does base saturation/nutrient balance affect nutrient recommendations?
the base saturation/nutrient balance approach has been suggested for Ca, Mg, and K
recommendations and has also been called cation saturation ratio. Here an optimum ratio of
cations is sought. Little scientific evidence supports this approach.
How does organic matter serve as a plant nutrient source?
as soil organic matter decomposes nutrients (primary N, P, S) are mineralized. Soil organic
matter retains cations in available forms. Plant residues are sources of nutrients as they
decompose (N, P, S, and all others). In some cases (high C:N) they will temporarily immobilize N.
Soluble nutrients (e.g. nitrate, chloride) can be leached out of the plant residues prior to
decomposition.
How can irrigation water serve as a nutrient source for plants?
irrigation water commonly contains calcium, magnesium, potassium, sulfate, and chloride and
may contain appreciable levels of metals like iron and manganese.
How can inorganic/organic fertilizer serve as a nutrient sources?
nutrients that remain in available forms (soluble, exchangeable cation, absorbed anion) from
fertilizer additions are nutrient sources for current and subsequent crops.
How can soil minerals serve as a nutrient source for plants?
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,soil minerals slowly dissolve to release nutrients
How can animal manure/processed waste water serve as a nutrient source for plants?
animal and human wastes are sources of nutrients as they decompose (N,S) and contain readily
available forms of other plant nutrients (P,K). Some animal wastes contain relatively high levels
of metals (copper)
How does urban/industrial waste serve as a nutrient source for plants?
This is a broad category and, so, plant nutrients in these wastes are quite variable. Some
mineralize N, others cause N immobilization depending on C:N ratio. These wastes may contain
high levels of metals (copper, zinc).
How does crop residue serve as a nutrient source for plants?
plant residue contains the essential elements that are returned to the soil system as the residue
decomposes and rainfall leaches soluble nutrients from the plant residue.
How do residual soil nutrients serve as a nutrient source for plants?
there is a carryover of nutrients from fertilizer and manure applications. a portion of these
nutrients may be available for subsequent crops if they remain in the soil in available forms.
How does shallow groundwater serve as a nutrient source for plants?
if plant roots reach shallow groundwater or groundwater moves to the root zone during
evapotranspiration, nutrients soluble in that groundwater can be a nutrient source.
Describe how the following influence nutrient loss/availability /// Describe environmental
conditions influencing the use of the following
**Urease inhibitors
- Designed to minimize losses from urea and ammoniacal fertilizers. N losses from urea/UAN can
occur when surface applied. If urea remains on the soil surface and is not incorporated or
moved into the soil by rainfall, it dissolves/converts to ammonium carbonate. The ammonium
carbonate increases soil pH, ammonium converts to ammonia and the ammonia is lost via
volatilization. Urease is the enzyme that controls the conversion of the urea to ammonium
carbonate.
- Urease inhibitors reduce the rate of the reaction and ammonia losses. Thus, urease inhibitors
are used where N losses occur in this manner.
Describe how the following influence nutrient loss/availability /// Describe environmental
conditions influencing the use of the following
**Nitrification inhibitors
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,- Nitrification inhibitors block the conversion of NH4+ to NO3-. In doing this, fertilizer N is
preserved in the NH4+ form. Without the inhibitor, the NH4+ is converted to NO3- which can be
leached or denitrified.
- Urease and nitrification inhibitors block microbial processes and the inhibitors effectiveness
declines as they are decomposed. Thus, environmental conditions that increase microbial
activity reduce the efficacy of these materials. They are most effective where activity is
maintained for a sufficient period of time that the crop will utilize the applied N fertilizer
effectively.
Describe how the following influence nutrient loss/availability /// Describe environmental
conditions influencing the use of the following
**Polymer coatings
- Fertilizers can be coated with polymers, plastics, and environmental S (s coated urea). These
coatings are porous or dissolve and vary in thickness. Water enters the fertilizer coatings and
dissolves nutrients making them plant available.
- Since nutrient release does not depend on microbial activity, these materials tend to release
nutrients in a more consistent manner than the organic fertilizers.
Describe how the following influence nutrient loss/availability
Describe environmental conditions influencing the use of the following
** Chelated formulations
- Used to keep nutrients in available forms. If a soil property (e.g. at high soil pH, iron forms
insoluble compounds) makes inorganic forms of the nutrient unavailable, chelates are often
used.
Anhydrous ammonia (NH3)
liquid under pressure, gas at reduced pressure (82-0-0); subject to many regulations
Urea ((NH2)2CO)
dry/granular (46-0-0); can volatilize when surface applied
Ammonium Nitrate (NH4NO3)
solid or liquid (34-0-0); can cause salt toxicity
UAN solution (Urea + NH4NO3)
liquid (28-0-0 to 32-0-0); urea portion can volatilize
Ammonium sulfate ((NH4)2SO4)
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, solid (21-0-0-24S); wont volatilize unless high soil pH; low salt toxicity potential
Triple superphosphate (TSP) ((Ca(H2PO4)2)
solid (0-46-0)
Mono-ammonium phosphate (MAP) (NH4H2PO4)
solid (11-52-0)
Diammonium phosphate (DAP) ((NH4)2HPO4)
solid (18-46-0)
Ammonium polyphosphate
liquid (10-34-0 or 11-37-0)
Potassium Chloride (MOP) (KCL)
solid (0-0-60)
Potassium sulfate (K2SO4)
solid (0-0-50)
Potassium nitrate (KNO3)
solid (13-0-44)
Potassium magnesium sulfate (K-Mag) (K2SO4 * MgSO4)
solid (0-0-22-11Mg-22S)
Define total availability
is the amount of nutrient that will ultimately be available to crop plants when the fertilizer has
reacted completely with soil and water
Define water solubility
is the portion of a fertilizer that dissolves in water over a short time releasing soluble nutrients
in the soil
Define guaranteed analysis
the minimum amount of N, P2O5, K2O, etc. in the fertilizer material. The Association of
American Plant Food Control Officials (AAPFCO) writes rules, definitions, and labeling standards
for fertilizer industry.
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