c     file: sdst.for

      subroutine sdst (x,dg,dg1,i)

c     + + + PURPOSE + + +
c     This subroutine initializes residue, nitorgen, and phosphorous amounts in
c     layers

c     + + + KEYWORDS + + +
c     Initialization

c     + + + LOCAL VARIABLES + + +
      integer i
      real dg, dg1, x(*)

c     + + + LOCAL DEFINITIONS + + +
c     dg    -
c     dg1   -
c     i     -
c     x     -

C      dimension x(10)

c     + + + END SPECIFICATIONS + + +

c     DATA E/'E'/
      if (x(i) .gt. 0.) go to 4
      if (i .gt. 1) go to 2
      x(1) = 1.
      go to 4
    2 x(i) = x(i-1) * dg * exp(-.01*dg)/dg1
c   3 EST(J,I)=E
    4 return
      end