c     file name: setbd.for

      real function setbd (sand, clay, om)

c     + + + PURPOSE + + +
c     the following function estimates settled soil bulk density from
c     intrinsic properties. see Rawls (1983) Soil Science 135, 123-125.

c     + + + AUTHOR + + +
c     Imam Elminyawi

c     + + + KEY WORDS + + +
c     wind erosion, soil processes, ....

c     + + + ARGUMENT DECLARATIONS + + +
      real clay, sand, om

c     + + + LOCAL VARIABLES + + +
      integer i, j
      real mbdtv (0:10,0:10), mbd

c     + + + LOCAL DEFINITIONS + + +
c     clay      - clay content
c     i
c     j
c     mbdtv
c     mbd       - mineral bulk density without organic matter
c     om        - organic matter
c     sand      - sand content
c     setbd     - settled bulk density

c     + + + END SPECIFICATIONS + + +

      data mbdtv /1.48,1.25,1.00,1.06,1.16,1.22,1.30,1.39,1.45,1.51,1.52
     &           ,1.52,1.40,1.19,1.25,1.32,1.40,1.52,1.58,1.63,1.65,0.
     &           ,1.52,1.40,1.25,1.35,1.45,1.53,1.60,1.64,1.72,0.,0.
     &           ,1.52,1.40,1.29,1.41,1.50,1.57,1.63,1.68,0.,0.,0.
     &           ,1.50,1.40,1.35,1.43,1.53,1.61,1.64,0.,0.,0.,0.
     &           ,1.46,1.40,1.40,1.43,1.53,1.62,0.,0.,0.,0.,0.
     &           ,1.45,1.40,1.38,1.42,1.50,0.,0.,0.,0.,0.,0.
     &           ,1.42,1.37,1.33,1.33,0.,0.,0.,0.,0.,0.,0.
     &           ,1.33,1.32,1.20,0.,0.,0.,0.,0.,0.,0.,0.
     &           ,1.23,1.18,0.,0.,0.,0.,0.,0.,0.,0.,0.
     &           ,1.15,0.,0.,0.,0.,0.,0.,0.,0.,0.,0./

      j = nint(clay*100.0/10.0)
      i = nint(sand*100.0/10.0)

      mbd = mbdtv(i,j)

      setbd = 100.0/ (((om*100.0) / 0.224)  + (100 -(om * 100.) )/ mbd)

      return
      end