Corn root length for plants grown with FGD applications was not different from that of used-wallboard treatment. Byproducts enhanced corn root growth but not that of soybean. Soybean was more sensitive to the materials than corn; therefore one should take into account the crop to which these materials will be applied. The reduction observed in soybean root length with increasing byproduct application rate may not occur if these materials are applied to soil which has higher buffering capacity than sand. Also in this study cups were not allowed to drain compared to field condition where drainage will occur.