Soil Flashcards
How is soil important for an arborist
relationship between tree root systems and the characteristics of soils in which they grow has a greater influence on the tree health than any other single factor. By knowing more about soil texture, structure, pH, and water holding capacity, the arborist will be better equipped to manage trees in an urban environment.
What is Soil
Soils are usually dominated by the geology of the soil parent material. By volume, ideal soils are composed of 45% mineral materials ( sand, silt, clay ), 50% open or pore space, and 5% organic matter and organisms. Over time soils develop layers due to rainfall, heating and cooling, chemical reactions and biological activities
What is the Soil profile
normally consists of five major horizons ( O, A, E, B, and C, ),
These layers can be distingui- shed by differences in color, texture, and smell, which can indicate varia- tions in drainage, organic and mineral content, and other characteristics changes.
What is the O layer
O horizon, is the organic layer of the top of the layer of soil profile that comprises of organic material in various stages of composition. It provides a source of nutrients for plants, and it buffers the soil from climatic extremes
What is A layer
is organic matter content is significantly less than that of the O horizon ( less than 20 percent organic matter). The A horizon contains most of the fine roots of trees and is typically biologically active. Although it is primarily composed of inorganic material ( sand, silt, and/ or clay), the A horizon is normally rich rich in organic matter, which gives this horizon its characteristic dark color
What is the E Horizon
when it exists, is found in these surface horizons and is lighter in color
What is the B Horizon
occurs below the A horizon ( and the E horizon, if present). It is a zone of accumulation where materials that have leached from the surface mix with soil particles from the lower parent materials.
What is the C layer
the deepest layer just above the bedrock and is composed of partially weathered parent material. Soil in this horizon is continually changing through the physical, chemical, and biological weathering of the parent material.
What area is the most favorable area for tree roots to grow
Most of the fine absorbing roots are most frequently found in the upper 6-10 inches of soil, and rarely are there any tree roots below than 3-4 ft.
What is Organic Matter
includes plants and animals that are alive, dead, or in some stage of decomposition. Organic matter improves soil structure, which results in increase water infiltration following rains and increase water- holding capacity of the soil; it also enhances root growth into more permeable soil (nitrates)
What is Pore Space
Refers to the amount of pores , or open space, between soil particles. Pore space may be formed due to the movement of roots, worms, and insects
Soil Texture affects this
What is Soil Texture
refers to relative fineness or coarseness of the soil particles, specifically the proportions of sand, silt, and clay
What is Loam Soil
a mixture of sand, silt and clay
very desirable medium that is used by farmers, gardeners, landscapers and property owners because of its very beneficial qualities.
What is Clay Soil
comprised of very fine mineral particles and not much organic materials. The resulting soil is quite sticky
What is Sandy Soil
generally coarse textured until 50 cm deep and consequently retain few nutrients and have a low water holding capacity. Q.palms
What is Silt Soil
Slippery when wet, not grainy or rocky. Soil itself can be called silt if its silt content is greater than 80%. When deposits of silt are compressed and the grains are pressed together, rocks such as siltstone form. Silt is created when rock is eroded, or worn away, by water and ice.
