Exam 15: Micronutrients and Other Trace Elements

Which of the following micronutrients becomes more available for plant uptake as soil pH is increased from pH 6 to pH 8?

Because many chelating agents are naturally occurring, a kilogram of zinc generally costs less in the form of zinc-chelate than in the form of zinc sulfate.

Molybdenum occurs in the soil solution as a complex anion similar to that formed by phosphorus.

Which method of application generally would require the greatest amount of iron to alleviate an iron deficiency in an orange grove?

Where the available supply of iron and zinc are low, deficiency of these elements can often be overcome by larger than normal applications of phosphorus fertilizer.

Simply spraying a solution to coat the seeds before planting often provides enough of which micronutrient to meet the needs of the crop?

Interveinal yellowing of the oldest leaves on a plant is a symptom that suggest a deficiency of Mn or Fe.

In the future, as food production is increased in countries around the world, micronutrient deficiencies are likely to become less of a problem than they are today.

Plant symptoms such as aborted fruits, dead terminal buds, and misshapen new leaves suggest a deficiency of which micronutrient?

Iron deficiency is most likely to occur under which of the following soil conditions?

A soluble iron chelate with a very high stability constant will be less effective as a fertilizer material than one with a lower stability constant.

Which micronutrient is particularly critical for legume plants because of its place in the nitrogenase enzyme that allows Rhizobia-infected legumes to utilize atmospheric nitrogen?

Once a micronutrient ion is introduced into the soil as a chelate, it will remain in that form until taken up by a plant or a microorganism.

In an alkaline soil, much of the iron in most iron chelates is rapidly replaced in the chelate complex by which other metallic nutrient?

Mycorrhizae help plants avoid toxicities of zinc, copper, and other micronutrients by decreasing the uptake of these elements from soil into the plant shoot.

When organic amendments such as animal or green manures are added to soils, micronutrient availability generally is enhanced by the production of natural chelating agents.

Dicot plants are thought to remove chelated micronutrients from their organic ligands before taking metallic cations into their roots.

Most micronutrients play essential roles in plant metabolism as enzyme activators.

Azaleas, pin oaks and other acid-soil loving forest plants have evolved very efficient mechanisms for extracting iron from soils.

Dolomitic limestone is a good material to fertilize acid soils with both for both Ca and Mg.