00473naa a2200145 a 450000100080000000500110000800800410001910000180006024501170007826000090019565000090020470000170021370000210023077300760025118357362013-09-25       1981    bl ---       0--  u    #d1 aBOLTON, E. F.  aEffect of fall and spring plowing at three depths on soil bulk density, porosity and moisture in Brookston clay.  c1981  aSolo1 aDIRKS, V. A.1 aMCDONNELL, M. M.  tCanadian Agricultural Engineering, Ottawagv. 23, n. 2, p. 71-76, 1981.