Nonionic Surfactant‐soil Interaction Effects on Barley Growth1

Abstract

AbstractResearch was conducted to integrate previously reported independent observations on surfactant adsorption, microbial degradation, uptake, and translocation, and on surfactant effects on plant growth in solution and soil cultures. Adsorption isotherms were measured for two nonionic surfactants and three soil materials. The shape of the adsorption isotherm was dependent upon both surfactant and soil properties. Barley (Hordeum vulgare L.) plants were grown in solution culture containing various concentrations of surfactant and in soil wet with surfactant solutions. Application of surfactant solution to soil reduced its toxicity to plants because of surfactant adsorption by the soil. The adsorption isotherm was used to calculate concentration of surfactant remaining in solution after application to soil. The effect of surfactant on plant growth was approximately the same in solution and soil cultures when the results were compared on the basis of solution concentration in the soil following adsorption. Less than 1% of the surfactant applied to soil was taken up and translocated in the barley plants. The difference between amount of a 14C‐labeled soil penetrant (an alkyl polyoxyethylene ether) applied and recovered in the soil and plant at the end of the experiment agreed with expected microbial degradation rates previously measured.