Fertilizer Sources and Application Flashcards
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Read the first 7 Fertilizer Sources and Application flashcards as text
Which fertilizer application timing strategy delivers nitrogen closest to peak crop demand, minimizing leaching risk?
Answer: Split application with starter plus side-dress at V6
Split application—starter at planting plus side-dress near peak uptake—synchronizes nitrogen supply with the period of highest crop demand, reducing leaching losses.
The '4R' nutrient stewardship framework stands for right source, right rate, right time, and:
Answer: Right place
The 4R framework stands for Right Source, Right Rate, Right Time, and Right Place—collectively improving nutrient use efficiency and environmental stewardship.
Which micronutrient fertilizer is most commonly applied to correct iron deficiency chlorosis in soybeans grown on calcareous soils?
Answer: Chelated iron (Fe-EDTA or Fe-EDDHA) applied as foliar or soil application
Chelated iron forms (EDTA or EDDHA) remain plant-available in high-pH calcareous soils where inorganic iron is rapidly fixed, making them the most effective treatment.
What is the primary environmental concern associated with excessive phosphorus fertilization on sandy soils near water bodies?
Answer: Phosphorus leaching leading to eutrophication of surface waters
On coarse sandy soils, phosphorus can leach into groundwater and reach surface water bodies, causing algal blooms and eutrophication.
Fertigation through drip irrigation is most advantageous because it:
Answer: Delivers soluble nutrients directly to the root zone with high precision and efficiency
Fertigation via drip irrigation places nutrients precisely in the active root zone, improving uptake efficiency and reducing runoff and volatilization losses.
Which of the following is a liming material rather than a fertilizer, but is often applied to improve nutrient availability?
Answer: Calcitic limestone (CaCO3)
Calcitic limestone is a liming material that raises soil pH, improving the availability of most macro and micronutrients rather than supplying large amounts of plant-available nutrients directly.
Nitrogen in urea-ammonium nitrate (UAN) solution is present in which three forms?
Answer: Urea, ammonium, and nitrate
UAN solution contains urea-N (~50%), ammonium-N (~25%), and nitrate-N (~25%), giving it a blend of fast- and slower-release nitrogen fractions.