00322nam a2200109Ia 450000500170000000800410001708200140005810000200007224500680009226000440016030000080020420260224040832.0260224s9999||||xx |||||||||||||| ||und||  a631.8 COL  aColwell, J. D.  0aComputations studies of soil fertility& fertilizer requirements  aSlough : Commonwealth Agr.Bureauxc1978  a297