Soils Exam 2

Master horizons

OAEBCR

Diagnostic horizons

Used for classifying soils

Soil phase

Subdivisions of a soil series that are separated based on properties important to land management such as slope, stoniness, texture of surface horizon, etc

Soil series

have relatively narrowly defined ranges in properties, i.e., they represent the “pure” concept of a soil type

Soil mapping unit

generally named after a soil series but often include other associated soils due to the limitations of delineating soils on a landscape

Entisols

Youngest and have an A but no B horizon; ochric epipedon over C or R

Inceptisols

Have and A and weak B (typically ochric epipedon over cambic subsoil)

Histosols

Organic soils; often wet, productive ecosystems

Gelisols

Have permafrost somewhere within the top 2 meters

Andisols

Formed from volcanic ash material

Aridisols

Occur in arid regions and have some subsoil development (B horizon present)

Mollisols

Have thick, dark A horizon and are very fertile grassland soils

Vertisols

Have swelling-clays and open cracks when dry; similar to mollisols otherwise

Alfisols

Have illuvial clay-rich subsoils (argillic horizon) and good fertility; warm, humid climates

Ultisols

Have illuvial clay-rich subsoils (argillic horizon), high acidity, and low to moderate fertility; more weathered

Oxisols

Extremely weathered, infertile, and must be fertilized and limed for agriculture; found in hot, humid tropics

Spodosols

Have illuvial Fe/Al-oxides and humus and are sandy (often E/albic horizon); found in cool coniferous forests; poor for agriculture

Factors that influence evapotranspiration

Soil and vegetation, weather, and humans (impervious surfaces)

Aquic

Wet with poor aeration; very wet (saturated)

Udic

Adequate water year-round; humid

Ustic

Moisture is limited but present during growing season; semiarid

Xeric

Most precipitation in winter with dry growing season (Mediterranean); dry summer, wet winter

Aridic

Water deficient; arid (desert)

Properties that influence soil water infiltration and storage

Soil texture, organic matter, structure, climate, topography, disturbance

Example of artificial soil drainage

Buried “tile lines” made of perforated plastic pipe

Pros of artificial soil drainage

Enhanced plant growth, improved access, reduced plant disease, more rapid soil warming, lower greenhouse gas emissions, removal of excess salts and capillary fringe effects, less frost heaving

Cons of artificial soil drainage

loss of wildlife habitat, loss of nutrient uptake by wetlands, increased leaching of nitrates, etc to groundwater, loss of soil organic matter, flooding problems

What are the three different irrigation methods

Furrow, sprinkler, and drip

Which irrigation method is the cheapest

Furrow

Which irrigation method is the most efficient

Drip

What is an environmental impact of the removal of colonial milldams

ammonium to oxidize to nitrate and flush downstream; leads to algal growth and O2 depletion

Three step involved in both wind and water erosion

Detachment, transport, and deposition

Three different types of water erosion

Sheet, rill, and gully

Sheet erosion

Relatively uniform

Rill erosion

Minor localized erosion

Gully erosion

Major localized erosion

Three different types of wind erosion

Soil creep, saltation, and suspension

Soil creep erosion

Sliding/rolling

Saltation erosion

Bouncing

Suspension erosion

Long-term/distance dispersal

Examples of BMPs

Plant presence/cover crops, soil moisture management, windbreaks, and installed soil covers

How do BMPs address erosion

Consider nutrient source, rate, application method, and timing; maximize plant uptake and minimize losses

What nutrients impact water quality

Nitrogen and phosphorous

Agriculture BMPs

nutrient management, cover crops, grazing, runoff control, mortality management

Urban BMPs

nutrient management, sediment control, bioretention, wetlands, urban forest planting

Forest BMPs

forest harvesting practices, non-urban stream restoration, shoreline erosion control

Point source pollution

directly from what caused it

Nonpoint source pollution

source is diffuse sources where the specific point of discharge is not identifiable

Animal waste management plan

<10 acres fertilized

Nutrient management plan

>10 acres fertilized or CAFOs

Elements of the Delaware Nutrient Management Plan

Plan identification, animal information, field maps, crop and nutrient information, voluntary BMPs, implementation records

Required practices of the Delaware Nutrient Management Plan

realistic yield goals, manure storage requirements, soil test and manure analysis, applications restrictions, record keeping and reporting

What is a function of nutrient cycling

Earthworms

What is a function of provision of food, fibre, and fuel

Soil organic matter

What is a function of flood regulation

Infiltration

Minimize disturbance

reduced till/no till, rotational grazing system

Maximize biodiversity

diverse crop rotations and species mixes, high soil organic matter levels, avoid factors that degrade soil, have proper pH and fertility

Maximize soil cover

plant cover crops, annual crops, and perennial crops, leave crop residues and living mulches on the ground

Maximize living roots

grow long-season or cover crop after a short-season crop, make sure soil food web has plenty of food

Species richness

number of species present in a habitat

Species evenness

the degree to which the various species are represented

Plastic soil

wet, easily molded soil

Friable soil

dryer soil, will break under pressure

How does planting a “tillage radish” as a cover crop influence soil heath, and subsequent corn or soybean growth

It helps dry out heavy clay soils to ease spring field operations and compaction and breaks apart compacted soil

What is a strategy for remediating saline soils

Applying more water than the plant needs to move salts below the rooting zone

1st definition of agroecology

a science that attempts to explain the functioning of agroecosystems

2nd definition of agroecology

a set of practices that permit farming in a more sustainable way

3rd definition of agroecology

a movement that seeks to make farming more ecologically sustainable and socially just

Recycling example

Compost application

Diversity example

Cover crops

Synergies example

Intercropping

Resilience example

Animal integration

Crop rotations relations

recycling, resilience, diversity, synergies, and efficiency

Agroforestry relations

resilience, recycling, diversity, efficiency, and synergies

two ways in which agroecosystems differ from natural ecosystems

1- Agroecosystems are human-made ecosystems, natural ecosystems are not

2- Natural ecosystems have more biological diversity than modern agroecosystems