Isotopic studies on the uptake of sulphur by pasture plants

摘要

Abstract A method for the direct introduction of 35S isotope into different soil depths under field conditions to study the uptake of sulphur by pasture plants is described. This method was designed to minimise bias and contamination during the introduction of the isotope. It involved the horizontal introduction of the isotope enclosed in water-soluble capsules. Recovery of 35S by the pasture plants indicated that when 35S was introduced at a depth of 22 cm the area above ground in which pasture plants were labelled extended little more than 15 cm from the line of placement. This lateral spread of 35S in the pasture plants varied according to the soil and the depth of application. The results may be explained in terms of the extent and nature of root development in the soil profile.