Erosion  Laboratory

Objectives

The erosion from the horseshoe grass cover are should be determined by had and then using the RUSLE program

Compare the two answer and explain any differences.

 

 

Lab introduction

 

Universal soil loss equation.

A= RKLSCP
where A= annual soil loss
R= erosivity of rain
K= soil erodibility factor
L and S are length and angle of slope factors
C= crop management factor
P= soil conservation factor.

 

 

 

 

R= the kinetic energy of the storm times the maximum 30 min intensity  and has values ranging form 10 to 400  Value for El Paso is 10 and for Albuquerque is 26.the units are ft tons acre/ inch hr yr  = average annual rainfall erosivity .

K is the soil erodibity factor representing the susceptibility of soil or surface material to erode, transport sediment at a given rate of runoff given a particular rainfall input as measured under a standard conditions. The standard condition is the unit plot  72.6 ft long with a 9 percent gradient , maintain in continuous fallow, tilled up and down the hill slope. The k value reflects the rat of soil loss per rainfall-runoff R erosion index. and has units of ton/ac . The values come from the soil survey table 14 and for a  harkley clay loam are 0.32 ton/ac. Values are corrected for rock factors for certain part of the United States.

See Soil Sersv4ey of Dona Ana County

LS is corrected using a graph. For a field with a 0% slope and 400 ft of length , the correction factor is 0.03. For a 2 % slope the value is 0.4. For a 9 % slope the value is 1.0

crop factor C

P conservation factor

 

Material and methods

Results

 

R= 10

K= 0.27 for for a sandy loam  

L= 350 ft

S= 3% 

ls= 0.6

c= 0.004

P= 1

 

A= 10 *0.27* 0.6*0.004 *1= 0.0064 ton/ac per year.  

find information on internet to determine the maximum allowable erosion rate to remain sustainable. Should be below 3 ton/ac