NITROGEN IN SOIL & PLANT GROWTH

These flashcards cover key concepts and vocabulary related to nitrogen in soil and plant growth, focusing on its roles, cycling, and impact on the environment.

Nitrogen

A macronutrient essential for plant growth, vital for amino acids, chlorophyll, and nucleic acids.

Amino acids

Building blocks of proteins that require nitrogen.

Chlorophyll

The green pigment in plants essential for photosynthesis that contains nitrogen.

Nucleic acids

Molecules such as DNA and RNA that contain nitrogen.

Chlorosis

A plant deficiency symptom characterized by yellowish or pale green colors due to low nitrogen.

Nitrate

An inorganic form of nitrogen (NO3-) that plants can absorb; contributes to potential leaching losses.

Ammonium

Inorganic form of nitrogen (NH4+) that can be absorbed by plants.

Immobilization

The process where soil microorganisms bind inorganic nitrogen into organic forms.

Mineralization

The process where microorganisms convert organic nitrogen into inorganic nitrogen.

Nitrification

Bacterial oxidation of ammonium to nitrate in soils.

Denitrification

Bacterial reduction of nitrate to nitrogen gas (N2), a significant loss of nitrogen from soil.

Hypoxia

A condition resulting from excessive nitrogen in aquatic environments, leading to low oxygen levels.

Fates of ammonium

Five possible outcomes for ammonium in soil including plant uptake, volatilization, immobilization, mineralization, and leaching.

N-fixation

The conversion of atmospheric nitrogen (N2) into a usable form for plants, primarily through bacteria.

Haber-Bosch process

An industrial method for synthesizing ammonia from nitrogen and hydrogen, requiring significant energy.

Biological N fixation

The conversion of atmospheric nitrogen into ammonia by bacteria, often in symbiotic relationships with plants.

High C:N ratio

Organic residues that, when decomposed, can lead to nitrogen immobilization.

Low C:N ratio

Organic residues that tend to release nitrogen when decomposed.

Organic nitrogen

Forms of nitrogen found in living organisms or organic matter.

Inorganic nitrogen

Mineral forms of nitrogen in the soil like ammonium and nitrate.

Plant available nitrogen

The fraction of nitrogen in soils that is readily available for plant uptake.

Ammonium fixation

The process by which ammonium is trapped or strongly bound by clay minerals.

Oversupply of nitrogen

Excess nitrogen leading to reduced fruit/grain quality and delayed plant maturity.

Leaching

The loss of nitrate from soil through water movement, causing environmental issues.

Soil fertility

The ability of soil to provide essential nutrients to plants, often impacted by nitrogen availability.

Nitrogen cycle

The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms.

Nitric acid

A strong acid (HNO3) produced in soil from nitrification processes.

Soil pH

A measure of acidity or alkalinity in soil that influences nutrient availability, including nitrogen.

Saturated soils

Soil conditions that favor denitrification and possible nitrogen loss.

Nitrosomonas

Bacteria involved in the first step of nitrification converting ammonium to nitrite.

Nitrobacter

Bacteria involved in the second step of nitrification converting nitrite to nitrate.

Fertilizer application

The addition of nutrients, specifically nitrogen, to soil for enhancing crop production.

Symbiotic relationship

Mutually beneficial interactions between certain plants (e.g., legumes) and nitrogen-fixing bacteria.

Eutrophication

Excessive nutrients in water bodies leading to algal blooms and oxygen depletion.

Bacterial reduction

The process by which bacteria transform nitrate into nitrogen gas, known as denitrification.

Environmental Protection Agency (EPA)

The U.S. governmental agency responsible for regulating and maintaining environmental quality.

Nutrient cycling

The movement and exchange of organic and inorganic matter back into the production of living matter.

Nitrogen leaching

The process of nitrogen compounds being washed away from the soil into groundwater.

Nitrate depression period

The time periods when nitrate levels are reduced in the soil due to microbial activity.

Wet and dry deposition

The processes by which nitrogen compounds are deposited from the atmosphere into the soil.

Nitrate (NO3-)

A negatively charged ion representing one of the key forms of nitrogen in soil.

Biomass nitrogen

Nitrogen found in the biomass of organisms in the soil, playing a role in nitrogen cycling.

Nitrogen deficiency symptoms

Visible indicators in plants showing a lack of sufficient nitrogen, such as stunted growth.

Nitrate contamination

The presence of excessive nitrate in water supplies, which can have health implications.

Hydrolysis

Chemical breakdown of a compound due to reaction with water, relevant in nitrogen mineralization.

Environmental factors

Various conditions such as temperature, moisture, and pH that affect nitrogen processes in soil.

Symbiotic N-fixation

Nitrogen fixation that occurs in mutualistic relationships between legumes and specific bacteria.