00450    a2200145   4500020001500000082001600015100002300031245008200054260006400136300001500200440003000215650002500245650001600270700001800286  a9157643490  a338.16bTOR  aTorssell, B. W. R.  aPredicting economic optimum and nitrogen balance in the ley - ruminant system  aUppasalabDepartment of Crop Production Sciencec1990g1990  a48p.c24cm  aCrop ProductionScience 10  aProduction efficient  aAgriculture  aEagerberg, B.