It had been supposed that unbalanced mineral nutrition was a possible causal factor for the declination of the artificial pastures(rye grass+white clover)on Nanshan cattle farm, Chengbu county, Hunan province. A trial of trace—element application on the farm shown that the pasture was in need of Mo, Zn and B. Lime applied to the soil would improve the efficiency of Mo but reduce the efficiency of Zn at the same time. So it was suggested that lime should not be used ...