A comparison of two methods of estimating the soil pore network available to protozoa

Two methods of estimating pore size distributions in different soil horizons are discussed and compared. These methods involve the use of either an image analyser or a camera lucida. The former method is rapid, but any enlargement of the original image of the soil pores yields inaccurate porosity measurements with the image analyser. The camera lucida method involves prolonged microscopical observations, but it can yield satisfactory pore size distributions of different soil horizons and when used with a microcomputer can be used to view a selected group of pores in three dimensions. The potential use of these methods in ecological studies of soil protozoa is discussed.