Plant Nutrition and Fertilization Flashcards

Which fertilization practice is recommended to reduce nutrient runoff into waterways in the US?

Answer: Use split applications and slow-release products

Split applications and slow-release products reduce nutrient loading in runoff by limiting the amount of soluble nutrients present in the soil at any one time.

Which micronutrient deficiency causes 'little leaf' or 'rosette' symptoms in fruit trees and ornamentals?

Answer: Zinc

Zinc deficiency causes shortened internodes and clustered small leaves ('little leaf' or 'rosette') because zinc is required for auxin synthesis.

The cation exchange capacity (CEC) of a soil influences its ability to:

Answer: Retain and supply positively charged nutrients

CEC measures how many cations (Ca²⁺, Mg²⁺, K⁺, NH₄⁺) a soil can hold on negatively charged exchange sites, directly affecting nutrient retention.

Foliar fertilization is most effective for correcting deficiencies of which type of nutrients?

Answer: Immobile micronutrients such as iron and manganese

Foliar sprays are particularly effective for immobile micronutrients like iron, manganese, and zinc because they bypass soil chemistry issues that limit uptake.

Compost is valued as a soil amendment partly because it improves nutrient retention. This is mainly due to its contribution of:

Answer: Cation exchange capacity via humus

The humic substances in finished compost carry significant negative charge, increasing CEC and the soil's ability to hold cations against leaching.

When is the BEST time to apply granular fertilizer to established deciduous trees in the US?

Answer: Late fall after leaf drop or early spring before bud break

Late fall or early spring applications allow nutrients to become available as roots resume active growth without stimulating lush growth that can be damaged by late frosts.