List four factors of soil formation
Answers
Answer:
so,the new formed soil .It was perfect for farming
Answer:
Minnesota is a land of geologically young soils with many different parent materials (Figure 1). The common factor among Minnesota soils is that they were formed by the last glacier in the northern United States, 11,000 to 14,000 years ago.
This may seem like a long time but is considered recent in the context of soil formation and geology. Figure 1 lists five major parent materials: Till, loess, lacustrine, outwash and till over bedrock.
Till
Till is predominant in the south-central, west-central and southwestern parts of the state. As the last glacier was melting, these materials were deposited.
Soils formed in this material generally have silty clay loam to silty clay textures, many different rock sizes and poor internal drainage. The poor drainage has a large influence on nitrogen management and cultural practices.
Loess
Loess is windblown, silt-sized material deposited after the glacier melted. These silt deposits can range in depth from a few inches to many feet. Soils formed in loess generally have silt loam textures and no rocks.
Most soils formed in loess occur in southeastern Minnesota where the loess deposits are on top of limestone or sandstone. Because of the porous state of the underlying materials in southeastern Minnesota, the soils are generally well-drained.
Loess in southwestern Minnesota is deposited over glacial till. Soils formed in this material are generally poorly drained and behave similarly to soils formed in glacial till. Erosion is a major concern for these soils because of the silt loam texture. Residue management becomes an important factor in maintaining high productivity.
Lacustrine
Lacustrine parent materials result from sediment deposited in lakes formed by glacial meltwater. The lakes existed long enough that the large particles, such as rocks and sand, were deposited immediately after the lake was formed, while the smaller clay-sized particles were deposited later.
An example is the soil formed under Glacial Lake Agassiz in northwestern Minnesota and eastern North Dakota (Red River Valley of the North). Soils formed in lacustrine deposits have clay, clay loam and silty clay loam textures, poor internal drainage and no rocks. Many soils in northwestern Minnesota were formed in lacustrine material.
Outwash
Outwash is material deposited on the edges of fast-running rivers from the melting ice of receding glaciers. This includes rocks, gravel, sand and other materials large enough to drop out of the water flow, as the river current continued transporting smaller particles.
Soils formed in outwash are excessively well-drained and have sand and sandy loam textures. Examples of Minnesota areas with soils formed in outwash include the Anoka Sand Plain, North Central Sands and Bonanza Valley regions in east-central, north-central and central Minnesota, respectively.
Till over bedrock
Till bedrock deposits occur in northeastern Minnesota. Materials from the glacier were deposited over bedrock, similar to south-central Minnesota but with material from different glacial ice.
There are also significant areas of soils formed directly from bedrock. These soils tend to be shallow and aren’t extensively used for crop production.
Climate
annual precipitation
Figure 2: Normal annual precipitation in Minnesota.
Temperature and precipitation
Temperature and precipitation influence how fast parent materials weather and, thus, soil properties such as mineral composition and organic matter content.
Temperature directly influences the speed of chemical reactions. The warmer the temperature, the faster reactions occur. Temperature fluctuations increase physical weathering of rocks.
Precipitation governs water movement in the soil. The amount of water the soil receives and the amount of evapotranspiration that occurs influence water movement. Normal annual precipitation in Minnesota is the least in the northwest corner at 16 inches, and increases as you go toward the southeast corner, where 34 inches is the normal annual precipitation (Figure 2).
Evapotranspiration
Evapotranspiration is the combination of water evaporated from the soil surface and water transpired by growing plants. As air temperatures increase, evapotranspiration increases. High evapotranspiration relative to precipitation means less water is available to move through the soil.
In Minnesota, the greatest evapotranspiration occurs in the southwestern part of the state and decreases as you go toward the northeastern corner.
Annual precipitation
Figure 3: Annual precipitation minus evapotranspiration (ET).
Moisture index
A leaching index or moisture index (Figure 3) is calculated by subtracting evapotranspiration from precipitation. This index is an indicator of average soil moisture conditions.
o
Explanation:
please mark as brainlist answer