2008-05-30_PERMIT FILE - M2008035

• Permit No: M2008035
• IBM Index Class Name: PERMIT FILE
• Doc Date: 5/30/2008
• Doc Name: New 112c application
• From: Yuma County
• To: DRMS
• Email Name: CBM
• Media Type: D
• Archive: No

Custom Soil Resource Report
Available water capacity refers to the quantity of waterthat the soil is capable of storing
for use by plants. The capacity for water storage is given in inches of water per inch
of soil for each soil layer. The capacity varies, depending on soil properties that affect
retention of water. The most important properties are the content of organic matter,
soil texture, bulk density, and soil structure. Available water capacity is an important
factor in the choice of plants or crops to be grown and in the design and management
of irrigation systems. Available water capacity is not an estimate of the quantity of
water actually available to plants at any given time.
Linear extensibility refers to the change in length of an unconfined clod as moisture
content is decreased from a moist to a dry state. It is an expression of the volume
change between the water content of the clod at 1/3- or 1/10-bar tension (33kPa or
10kPa tension) and oven dryness. The volume change is reported in the table as
percent change for the whole soil. The amount and type of clay minerals in the soil
influence volume change.
Linear extensibility is used to determine the shrink-swell potential of soils. The shrink-
swell potential is low if the soil has a linear extensibility of less than 3 percent; moderate
if 3 to 6 percent; high if 6 to 9 percent; and very high if more than 9 percent. If the
linear extensibility is more than 3, shrinking and swelling can cause damage to
buildings, roads, and other structures and to plant roots. Special design commonly is
needed.
Organic matter is the plant and animal residue in the soil at various stages of
decomposition. In this table, the estimated content of organic matter is expressed as
a percentage, by weight, of the soil material that is less than 2 millimeters in diameter.
The content of organic matter in a soil can be maintained by returning crop residue to
the soil.
Organic matter has a positive effect on available water capacity, water infiltration, soil
organism activity, and tilth. It is a source of nitrogen and other nutrients for crops and
soil organisms.
Erosion factors are shown in the table as the K factor (Kw and Kf) and the T factor.
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by water.
Factor K is one of six factors used in the Universal Soil Loss Equation (USLE) and the
Revised Universal Soil Loss Equation (RUSLE) to predict the average annual rate of
soil loss by sheet and rill erosion in tons per acre per year. The estimates are based
primarily on percentage of silt, sand, and organic matter and on soil structure and Ksat.
Values of K range from 0.02 to 0.69. Other factors being equal, the higher the value,
the more susceptible the soil is to sheet and rill erosion by water.
Erosion factor Kw indicates the erodibility of the whole soil. The estimates are modified
by the presence of rock fragments.
Erosion factor Kf indicates the erodibility of the fine-earth fraction, or the material less
than 2 millimeters in size.
Erosion factor T is an estimate of the maximum average annual rate of soil erosion by
wind and/or water that can occur without affecting crop productivity over a sustained
period. The rate is in tons per acre per year.
Wind erodibility groups are made up of soils that have similar properties affecting their
susceptibility to wind erosion in cultivated areas. The soils assigned to group 1 are the
most susceptible to wind erosion, and those assigned to group 8 are the least
susceptible. The groups are described in the "National Soil Survey Handbook."
Wind erodibility index is a numerical value indicating the susceptibility of soil to wind
erosion, or the tons per acre per year that can be expected to be lost to wind erosion.
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