Soil Formation

What is Soil? Soil is a combination of particles of rocks, minerals, and organic matter produced through the weathering process

What process makes soil?

Weathering and Organic Decay

What is Organic Matter?

Organic Matter is materials which have come from Living Things

What are Soil Horizons?

Soil Horizons are Distinct zones in the soil that develop as a result of the weathering process

Soil Horizons

A - Horizon A : topsoil: upper layer of soil with a matrix of inorganic material; much organic matter (HUMUS) and many creatures; zone of greatest biological activity

B - Horizon B : accumulation layer: minerals leached from layer A, precipitate or accumulate here, sometimes forming an impermeable barrier

C - Horizon C : weathered rock: little organic material, perhaps large roots; directly above solid Rock

The Thickness and Depth of Soil Horizons depends on:

The Thickness and Depth of Soil Horizons depends on: - Length of Weathering - Composition of Parent Material - CLIMATE

What does Biologic Activity mean?

Biologic Activity is the presence and actions of plant and animal life within a soil

Changes that occur as a Soil becomes More Mature

Changes that occur as a Soil becomes More Mature 1 - Increased Depth

Changes that occur as a Soil becomes More Mature 2 - Development of Distinct Horizons

Changes that occur as a Soil becomes More Mature 3 - Additional Plant Growth

Changes that occur as a Soil becomes More Mature 4 - Increased Permeability and Capillarity

Changes that occur as a Soil becomes More Mature 5 - Increased Animal Activity

What is Humus? Humus it the decayed plant and animal matter in the A horizon

What do the arrows represent on the top of the soil profiles What do the arrows represent on the top of the soil profiles? Time and Weathering

What is the most important factor influencing or determining the composition of soil?

What is the most important factor influencing or determining the composition of soil? CLIMATE

What does Parent Rock mean with respect to Soil?

Parent rock is the original rock that the sediment which makes up the major part of the soil weathered from.

What is Transported Soil?

Transported Soil is soil made of sediment that has been moved by an agent of erosion

What is Residual Soil?

Residual Soil is soil that has developed directly over the parent material

If a forest soil and a prairie soil have the same parent rock from which they are made, why will the two soils be different?

Forests and Prairies have different Organic Matter and different Climates associated with them.

Soil Conservation

Soil Conservation Plowing Furrows Strip Cropping Terracing Cover Crops Wind Belts

PLOWING breaks up hard layers forming from leaching

Strip Cropping

Terracing

Terracing is one of the oldest and most efficient means of saving soil and water (Pipkin and Trent, 1997). A terrace is a flattened area that catches and temporarily stores or slows water run-off on moderate to steep slopes (USDA Soil Conservation Service, 1992). By slowing down the rate of surface water run-off, terracing can significantly reduce soil erosion. The art of terracing is an ancient soil conserving practice that has been used for many centuries to prevent soil erosion within agricultural land. In central China, for example, where steep slopes are underlain by erodible deposits of wind-blown silts, terracing has been a major factor in reducing soil loss (Skinner and Porter, 1997). Terracing has been used in China for centuries to 3

Cover Crops

COVER CROPS IN AGRICULTURE - AN OLD NEW CONCEPT History COVER CROPS IN AGRICULTURE - AN OLD NEW CONCEPT History. Cover crops were used by the Romans and Ancient Greeks as green manures, along with animal manures, to improve soil fertility. Since the Roman and the Greek empires occupied the semi-arid and arid regions around the Mediterranean Sea along Southern Europe, West Asia and North Africa, they used winter annual legumes such as vetch (Vicia spp.) and clover (Trifolium spp.) to fix nitrogen, recycle nutrients, add organic matter to the soil, and reduce soil erosion. Because rain in that region fell during the winter months (November through February), they took advantage of the rainy, mild season to grow the legumes and plow them under by the end of the rainy season at which time they seeded their main wheat crop. PRESENT USES OF COVER CROPS Cover crops have more uses in present agriculture than they had in the past. The expansion in use is the result of new species and varieties with better adaptation to adverse climatic conditions including high and low temperature, drought, flood and soil salinity tolerance, high biomass and nitrogen fixing efficiency, and resistance to pests. In addition, there have been great advances in management practices of these cover crops to meet the needs of changing agriculture, particularly in the area of sustainable agricultural systems which reduce soil and nutrient losses and conserve natural resources.

Wind Belts

Wind Belts

Furrows