AGR1110 Lecture 6 Topic 2: Crop Production and Soils

Flashcards covering key concepts from AGR1110 Lecture 6, Topic 2, including global land use, soil components, soil types, soil degradation, pests, and pest/weed management strategies.

Earth's Surface Land Area

29% of Earth's surface, totaling 149 Million km².

Habitable Land

71% of the land surface (104 Million km²), excluding glaciers and barren land.

Agricultural Land Use

50% of habitable land (51 Million km²), with 77% for livestock and 23% for crops.

O Horizon

The top layer of soil, mostly organic matter such as decomposing leaves.

A Horizon (Topsoil)

Mostly minerals from parent material with incorporated organic matter, good for plants and organisms.

E Horizon

A soil layer leached of clay, minerals, and organic matter, leaving concentrated sand and silt particles; often found in older and forest soils.

B Horizon

A soil layer rich in minerals that leached (moved down) from the A or E horizons and accumulated here.

Parent Material

The deposit at Earth’s surface from which the soil developed.

Bedrock

A mass of rock (e.g., granite, basalt) that forms the parent material for some soils, located under the C horizon.

Soil Orders

Classifications of soils generally based on distinctive sets of soil horizon characteristics.

Luvisolic Soil Order

Predominant in the agricultural soils of S.W. Ontario.

Brunisolic Soil Order

Primarily found in Manitoba.

Chernozemic Soil Order

Mostly found in Saskatchewan.

Soil Texture

Defined by the percentage of sand, silt, and clay particles in the soil; fixed for a given soil and influences water interaction.

Soil Structure

How the sand, silt, and clay particles are bound together; can be changed by farming practices.

Heavy Soils

Soils with high clay content that present challenges with drainage, tillage, and colder temperatures.

Light Soils

Soils with higher sand content.

Acidic Soil

A soil condition common in wet regions (tropics, sub-tropics, parts of Ontario/Quebec) due to leaching of Ca++ and Mg++ by heavy/acid rains, leading to nutrient unavailability and aluminum toxicity.

Aluminum Toxicity

A problem in acidic soils where aluminum becomes soluble and hinders nutrient availability for plants.

Salinization

The increasing amounts of salt in soil, caused by moisture evaporation drawing underground salt to the surface, particularly in arid, high-temperature regions.

Topsoil Loss

The degradation of the uppermost layer of soil, primarily due to erosion (water/wind) and tillage; nature replaces one inch in approximately 500 years.

Soil Degradation

Loss of agricultural land qualities due to erosion, salinization, acidity, and poor agricultural practices; ~40% of global agricultural land is degraded.

Erosion

The wearing away, detachment, and movement of soil or rock by natural agents (rain, wind, ice, gravity) or anthropogenic agents (tillage).

Causes of Soil Erosion

Wind, water, and tillage.

Erosion Reduction Practices

Techniques like reduced tillage, waterways, cover crops, and windbreaks used to minimize soil loss.

Pest

An organism that competes with a crop for resources or uses the crop as a resource, leading to economic loss.

Pest Management

The strategy of reducing pest populations to levels that do not cause economic loss, rather than complete elimination.

Pathogen

A type of pest causing diseases, including bacterial, viral, and fungal organisms.

Pathogen Management Methods (Prevention)

Cultivar selection, removal of secondary hosts, sanitation, crop rotation, timely planting, adequate nutrients, and avoiding disease-promoting microclimates.

Pathogen Management Methods (Protection)

Application of fungicides.

Stem Rust (Puccinia graminis)

A wheat disease for which barberry serves as a secondary host, where the pathogen can build up inoculum.

Genetic Resistance (Sr31)

A successful gene from rye transferred into wheat, providing resistance to stem rust and increasing grain yield.

Weed Management Methods

Competition (narrow rows, high plant density), allelopathy, mechanical/physical removal (tillage, burning, mowing, flooding), and herbicides.

Allelopathy

The chemical inhibition of one plant (e.g., weeds) by another (e.g., winter rye, brassicas) through the release of chemical compounds.

Herbicides

Chemicals used to kill or inhibit the growth of unwanted plants (weeds).

Pre-emerge Herbicide

A type of herbicide applied before weeds emerge from the soil.

Post-emerge Herbicide

A type of herbicide applied after weeds have emerged from the soil.

Selective Herbicide

A type of herbicide designed to kill specific types of weeds without harming the crop.

Non-selective Herbicide

A type of herbicide that kills most plant types it contacts.

EPSP Synthase

An enzyme essential for the synthesis of aromatic amino acids (Tryptophan, Tyrosine, Phenylalanine), which is the cellular target of the herbicide Round-Up (Glyphosate).

Herbicide Resistance

The inherited ability of a weed population to survive and reproduce after exposure to a herbicide dose that would normally be lethal.

Strategies to Limit Herbicide Resistance

Crop rotation, use of cover crops, rotation of herbicides with different modes of action, and applying the correct dose (not too low).