Exam 37: Soil and Plant Nutrition

In west Texas, cotton has become an important crop in the last several decades. However, in this hot, dry part of the country there is little rainfall, so farmers irrigate their cotton fields. They must also regularly fertilize the cotton fields because the soil is very sandy. The figure below shows the record of annual productivity (measured in kilograms of cotton per hectare of land) since 1960 in a west Texas cotton field. Use these data to answer the following questions. -If you were the county agriculture agent, what would be the best advice you could give the farmer who owns the field under study in the above figure?

Which two elements make up more than 90% of the dry weight of plants?

If an African violet has chlorosis, which of the following elements might be a useful addition to the soil?

Which of the following, if used as a fertilizer, would be most immediately available for plant uptake?

What soil(s)is (are)the most fertile?

Which of the following elements is incorrectly paired with its function in a plant?

Which of the following habitats would most likely have a high proportion of species of plants that are in symbiotic association with nitrogen-fixing bacteria?

Micronutrients are needed in very small amounts because

What is a major function of magnesium in plants?

In what way do nitrogen compounds differ from other minerals needed by plants?

Synthesis of which of the following compounds in a mature leaf would be least impacted by a temporary soil nitrogen deficiency?

Two groups of tomatoes were grown under laboratory conditions, one with humus added to the soil and one a control without humus. The leaves of the plants grown without humus were yellowish (less green)compared with those of the plants grown in humus-enriched soil. The best explanation for this difference is that

Which of the following essential nutrients plays an essential role in the opening and closing of the stomatal aperture?

All of the following contributed to the dust bowl in the American southwest during the 1930s except

Why does overwatering a plant kill it?

How would you determine if certain minerals are essential for plant growth?

In the 1640s, Jan Baptista van Helmont planted a small willow in a pot that contained 90.9 kg of soil. After five years, the plant weighed 76.8 kg, but only 0.06 kg of soil had disappeared from the pot. What did van Helmont conclude from this experiment?

A group of 10 tomato plants are germinated and maintained in a large tray with no drainage. After several weeks they all begin to wilt and die despite repeated watering and fertilization. The most likely cause of this die-off is

Rhizobacteria aid plant growth in all the following ways, except

Which of the following elements, if increased in concentration, would increase the stability of cell walls?