The effect of sulphur, nitrogen fertilization and inoculation with Rhizobium meliloti, on the growth and chemical content of alfalfa and sweet clover in pot culture
It is a well known fact that applications of sulphur to sulphur-deficient soils will very substantially increase the growth of legumes. However, applications of sulphur on the same soils do not necessarily increase the grain production of of cereal crops. Previous workers have suggested that the marked effects of sulphates on leguminous plants can result either from a fertilizer action on tbe host plant, or through their influence on the growth of nodule bacteria. One of the major objectives in this study was to establish which, if either, of these two factors was providing the main stimulus to the legume crop. To achieve this objective inoculated and uninoculated legumes were grown with and without sulphur and with and without nitrogen fertilizer. At a suitable stage of growth yield data, and total nitrogen content of the plants and of the medium in which they were grown, were determined.