depth increments in centimeters will be: 25-35 and at 15 em intervals below 35 em. 0-2, 2-5, 5-10, 10-15, 15-25, If a soil horizon is encountered the interface lines will be chosen as the increments from the horizon rather than the fixed nominal increments from the surface. Locations.for the collection of soil samples will be chosen on the basis of (1) random selection and (2) ground or aerial survey meter readings. These are described below: ++ Aa leAnN sameal A attae|eR tn 8 9 a tin a A. . _ Samples collected on-the basis of random selection. i. Each island will be divided by a narrow grid, (i.e., approximately 2500 points or 50' x 50' grid whichever is smaller), All areas defined by such a grid will be numbered. If stratification is desired and in order, the strata will be chosen and indicated on the grid network. co Individual sample areas will then be chosen within each stratification or grid by selection of the appropriate coordinate number utilizing random number tables. The number of samples per island or group has been previously determined through consideration of desired goals and statistical significance, The exact location of the sample collection is to be the center of the area chosen by the random number technique described in No, 3 above. It is realized that the determination of such a point with any great precision or accuracy in the field is technically impractical in most cases. It is most important however that the sample collector make every reasonable effort to locate the position as closely as.possible. In particular, the sample ne, PN should come from within a 10 foot by 10 foot area defined as the . center area of the grid point. Ideally, the sample will come from the exact center of this limited area as just stated. In the field the location will be identified as indicated on the map but will be located probably by pacing or other field direction. The spot so determined by such pacing will be the actual spot at the end of the designated number of paces, and no other. If there is some obstacle to sampling at this specified location (e.g., a concrete pad) then that fact should be recorded in the field and no sample taken. a ~h.