Introduction of lucerne into acid soils

The key to pasture improvement in the tussock country of the South Island is in the introduction of high-producing legumes. White, red and alsike clovers have been widely used with considerable success. Lucerne, as yet, is much less important, even though it has been shown by Iversen (1965) that on droughty soils it can produce much more dry matter than conventional pastures. One of the main reasons for the lesser use of lucerne is the difficulty in establishing the plant by surface sowing methods, particularly in acid soils. Lucerne is particularly sensitive to acid soil conditions which affect establishment and growth in several ways. There are two possible approaches to overcoming problems of establishing lucerne on acid soils. The usual method is to modify the soil environment to suit the plant, by heavy broadcast liming. This is often uneconomic in tussock country owing to high transport costs. Another approach is to select strains of R. meliloti and species of lucerne which are more tolerant of acid soils. The latter approach has distinct possibilities, but, at present, it is a relatively new field. At Lincoln College an attempt is being made to combine both approaches in overcoming establishment problems in the tussock country