Soil Management & Fertilization Techniques Flashcards

What is biochar and how can it benefit tree soil health?

Answer: It is pyrolyzed organic material that improves soil structure, water retention, nutrient holding capacity, and microbial habitat when incorporated into the root zone

Biochar is organic matter (wood, agricultural waste) heated in a low-oxygen environment. The resulting porous carbon material improves soil water retention, CEC, microbial colonization, and soil structure when mixed into the root zone.

What is the difference between macronutrients and micronutrients in tree nutrition, and why is this distinction important?

Answer: Macronutrients (N, P, K, Ca, Mg, S) are needed in large quantities; micronutrients (Fe, Mn, Zn, Cu, B, Mo) in trace amounts — both are essential, and excess micronutrients can be toxic

Macronutrients are required in relatively large amounts for structural and metabolic functions. Micronutrients are needed in very small (trace) quantities but are equally essential — and importantly, even slight excess of micronutrients can cause toxicity.

How does gypsum (calcium sulfate) improve sodic soils for tree growth?

Answer: Calcium ions from gypsum displace sodium ions on clay particles, improving soil structure and reducing sodium toxicity to roots

Gypsum provides calcium ions that replace sodium ions on the cation exchange sites of clay particles. This reduces sodium toxicity, restores clay particle aggregation (improving structure and drainage), and the displaced sodium can be leached from the profile.

What is the principle behind foliar fertilization and when is it most appropriate for trees?

Answer: It involves spraying liquid fertilizer on leaves for direct absorption through stomata and cuticle, best used for rapid correction of micronutrient deficiencies

Foliar fertilization sprays dissolved nutrients directly onto leaves, where they are absorbed through stomata and the leaf cuticle. It is most useful for quickly correcting micronutrient deficiencies (like iron chlorosis) while longer-term soil corrections take effect.

What is the environmental concern with phosphorus runoff from over-fertilization of landscape trees, and how can arborists minimize this risk?

Answer: Excess phosphorus washes into waterways causing algal blooms, oxygen depletion, and aquatic ecosystem damage — arborists should test soil and apply phosphorus only when deficiency is confirmed

Phosphorus is the primary nutrient triggering eutrophication — algal blooms in lakes and streams that deplete dissolved oxygen and kill aquatic life. Arborists should only apply phosphorus when soil tests confirm deficiency, not as a default component of fertilizer programs.

How does the use of compost tea as a soil drench differ from applying solid compost as a soil amendment for trees?

Answer: Compost tea primarily introduces beneficial microorganisms and their metabolites to the root zone as a liquid inoculant, while solid compost provides sustained organic matter, nutrients, and soil structure improvement

Compost tea is a liquid extract that delivers a concentrated dose of beneficial microorganisms and soluble nutrients to the root zone. Solid compost provides longer-term benefits: sustained nutrient release, soil structure improvement, and ongoing microbial habitat.