00309nam a2200109Ia 450000500170000000800410001708200120005810000200007024500610009026000400015130000080019120260224040835.0260224s9999||||xx |||||||||||||| ||und||  a633 OSC  aOschwald, W.R.  0aCrop residue management systems: proceeding of symposium  aAmerican: Society of Agronomyc1979  a248