What is the unit used in USLE?
A represents the potential long-term average annual soil loss in tonnes per hectare (tons per acre) per year. This is the amount, which is compared to the “tolerable soil loss” limits.
How is USLE calculated?
The Universal Soil Loss Equation, or USLE, predicts the average annual soil loss “A” per unit area. The equation is A = R x K x L x S x C x P and multiplies various factors to arrive at the annual erosion rate.
What is K in USLE?
In the Universal Soil Loss Equation (USLE), the soil erodibility factor (K) corresponds to the collective effects of the detachment susceptibility of soil and the sediment transportability as well as the amount and rate of runoff under a given rainfall erosivity.
How is USLE LS factor calculated?
The equations for calculating LS in the RUSLE are:(1) LS = L ⋅ S (2) L = λ / 22.13 m (3) m = β / 1 + β (4) β = sin θ / 3 ⋅ sin θ 0.8 + 0.56 (5) S = 10.8 ⋅ sin θ + 0.03 θ < 9 % S = 16.8 ⋅ sin θ − 0.5 θ ≥ 9 % where λ is the slope length (m), m is a variable length-slope exponent, β is a factor that varies with slope …
What is the difference between USLE and RUSLE?
RUSLE also captures better than USLE that long rains can saturate the soil, leading to reduced intake and greater erosional runoff. In contrast with USLE, RUSLE can handle converging and diverging terrain and considers areas with net sedimentation.
Why is USLE important?
The Universal Soil Loss Equation (USLE) is hailed as one of the most significant developments in soil and water conservation in the 20 thcentury. It is an empirical technology that has been applied around the world to estimate soil erosion by raindrop impact and surface runoff.
What is soil K factor?
The K Factor is an index which quantifies the relative susceptibility of the soil to sheet and rill erosion. • K Factor is used in the RUSLE2 soil loss prediction equation. Values range from 0.02 for the least erodible soils to 0.64 for the most erodible.
Why is the USLE important?
What is the difference between USLE and Musle?
The (MUSLE) model (Williams 1975), is a modified version of the USLE model (Wischmeier and Smith 1965). This model replaced the rainfall factor (R) with instantaneous peak flows and total runoff factor to predict soil erosion.
What is the limitation of USLE?
The most commonly cited limitation of the (R)USLE models is their reduced applicability to regions outside of the United States of America (Aksoy and Kavvas, 2005; Naipal et al., 2015; Sadeghi et al., 2014). The original USLE was formulated based on soil erosion studies on agricultural land in the USA.
Who developed USLE?
The USLE was developed in the U.S., based on soil erosion data collected beginning in the 1930s by the U.S. Department of Agriculture (USDA) Soil Conservation Service (now the USDA Natural Resources Conservation Service).
What is K value for soil?
What is the K Factor? The K Factor is an index which quantifies the relative susceptibility of the soil to sheet and rill erosion. K Factor is used in the RUSLE2 soil loss prediction equation. Values range from 0.02 for the least erodible soils to 0.64 for the most erodible.
What is Erosivity and erodibility?
Abstract. Conceptually, rainfall erosivity is the capacity of rain to produce erosion, whereas soil erodibility is the susceptibility of the soil to be eroded.
Where is USLE model used?
The USLE or one of its derivatives are main models used by United States government agencies to measure water erosion.
What modified USLE?
The Modified Universal Soil Loss Equation (MUSLE) (Williams 1975) was developed as a watershed-based model to estimate the sediment yield produced by each individual storm event.
What is K value of subgrade?
Relation of load, deflection and modulus of subgrade reaction (k). The value of k is in terms of MPa/m (pounds per square inch per inch of deflection, or pounds per cubic inch – pci) and ranges from about 13.5 MPa/m (50 pci) for weak support, to over 270 MPa/m (1000 pci) for strong support.
What does a high K factor mean?
K factor is soil erodibility factor which represents both susceptibility of soil to erosion and the rate of runoff, as measured under the standard unit plot condition. Soils high in clay have low K values, about 0.05 to 0.15, because they resistant to detachment.
What is the unit of a in the USLE equation?
The term ‘A’ of universal soil loss equation (USLE) represents the annual soil loss per unit area per unit time. Since, the factors LS, C and P are dimensionless, hence unit of A is the multiplication of the units of factor R and K, only. The SI unit of A is the “kg per sq. m or metric tons per hectare”.
What is the SI system of measurement?
The SI is intended to be an evolving system; units and prefixes are created and unit definitions are modified through international agreement as the technology of measurement progresses and the precision of measurements improves.
What is the SI unit of length?
Unit of length, meter (m): Meter is the SI unit of length and is defined by taking the fixed value of the speed of light in vacuum. It is expressed as m.s -1.
What does USLE stand for?
Background. The Universal Soil Loss Equation (USLE) predicts the long-term average annual rate of erosion on a field slope based on rainfall pattern, soil type, topography, crop system and management practices. USLE only predicts the amount of soil loss that results from sheet or rill erosion on a single slope and does not account