The ecology of tussock grasslands: Some soils of the tussock grasslands
This paper discusses soils of the fescue tussock grasslands and the snow tussock grasslands of the South Island. These cover the floors and mountain slopes of the dry in- land basins, mountain valleys and adjoining mountains. I have chosen these grasslands because the question of their utilisation is quite important. The soils fall into three categories, namely, the Alexandra, Omarama and Kaikoura soils. They belong to a se- quence in which the degree of weathering, which is the distinguishing character of the soils, increases from the Alexandra to the Kaikoura soils.
The Alexandra soils are present in the driest parts of ihe basins under rainfalls of 12in. to 17in., and support mainly desert plants, the original tussock cover having been destroyed by burning and grazing. These soils have progressed little further than the weathering of the rock. Minerals are fresh, grain size is large, the soil contains many large grains, and the mineral particles are almost free from colloid coat- ings. The colour of the sub-soil, therefore, approximates the colour of the broken rock, which is grey to brown grey.