Application of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) generally reduced dry weight of tops and roots of corn and Pinus radiata seedlings. Simazine always increased top-root ratios of corn but generally decreased those of pine seedlings. Simazine increased significantly the uptake of N by corn in all soils; of Mg and P in limed, and of K in acidified soils. Aluminum sulfate decreased injury from simazine. Lime at 3 tons per acre mixed into the soil exerted a synergistic effect on the activity of 12 pounds per acre of simazine and killed all pine seedlings in the 7th or 8th week after sowing. The death of the seedlings was. caused by excess calcium ions and not by pH.