Soil sorption and alfalfa uptake of strychnine

Using application rates of 52-1040 mg/L strychnine, sorption isotherms were developed on three Nevada soils. Strychnine was found to sorb strongly to the three soils studied; however, isotherms were all nonlinear and the extent of sorption varied with each soil. Desorption characteristics paralleled sorption isotherms, indicating reversibility. An apparent relationship between specific surface area, cation exchange capacity (CEC), and total strychnine sorption was noted. Strychnine movement through soil columns under saturated flow was also investigated for the three soils. Potential uptake of strychnine in alfalfa was investigated by applying treated milo bait to the base of alfalfa plants at rates that exceeded normal rodent treatments. Strychnine was not detected in whole alfalfa samples taken 4 and 11 d following treatment.