Yorkshire fog

Seedlings of five native tussock species grown in the glasshouse on mountain subsoil showed outstanding responses to nitrogen and phosphorus fertiliser in combination. The most vigorous species was silver tussock but this produced less dry matter than an introduced grass, Yorkshire fog, grown on the same soil. Tussocks in general responded positively to applications of magnesium and potassium but growth was depressed by lime.

The low level of plant nutrients in exposed high-altitude subsoils, and the effects of soil frost and needle ice on plants attempting to colonise these subsoils combine to make natural revegetation very difficult. Artificial revegetation trials established in 1965 at three sites in the Canterbury mountains tested the effect of a fertiliser mixture which supplied a wide range of nutrients, and compared ten herbaceous species as providers of an initial protective cover, and of a cover that would persist.