2.4. Experimental
Using an ÔArc-View version 3.1Õ Geographic Information
System (GIS), the field was divided into 25-m
grid squares to give a total of 124 ÔpotentialÕ sampling
points at each grid node (Fig. 2(a)). Twenty of these
points, which fell on or close to the existing field
boundaries, were subsequently omitted to minimise
edge eects, leaving a total of 104 ÔactualÕ sampling
points.