H. RIEKERK and S, P. GESSEL 1365 Toble 1. Rates of application of ®P, ®®Rb, and ™Ca — Spring mCifin2 ‘Yotal mCi . ™ wey 0.018 0.017 0.009 12 i0 6 1963 Fall mCifin.2 ‘Fotal mCi 0.016 0.023 0.010 «et elements is given in the tables and iv." as parts per million (ppm) and expresses tw “caction of the radionuclide recovered in a wr This can be converted to per cent by tanne by 10,000, RESULTS AND DISCUSSION Talc 1 presents information concerning the umf application of the tracers. Larger uw. nts have been applied during [964 because "*'- emphasis on the measurement of uptake mGifin.2 ‘Votal mCi 0.056 17 25 is! 1964 Spring O.VEL 0.018 Fall mCifin.2 Total mCi 102 0.056 200 32 100 O11! 0.017 202 30 radioactivity after subtraction of leaching losses. Table 2 presents the totals leached during the various periods of sampling. The ratios between the amounts released by the forest floor and the surface soil during similar periods of leaching indicate the degree of retention in the surface soil. Phosphorus and rubidium appearto be retained more thancal- cium. For phosphorus this might be related to the high iron content of the soil as indicated by the presence of iron concretions throughout the i rrns and subsequent return to the soil with surface soil. A potassium deficiency of trees in Tc count data have been corrected for decay fixation in the soil," and very likely also rubidium. Calcium has also been reported to move throughthe soil at a low rate. Some variation between the levels of total » etall and rainwash. 2 background radiation due to fallout prodwx The corrected data were converted to "per rain/ml, and to ppm of the remaining the general areca mayindicate a high potassium Table 2. Parts per million* of =P, 88Rb and Ca released by the forest floor and surface soil ‘t'r of application Spring ppm days 1963 Fall ppm days XP Torest floor Surface sil Ratio 149,000 31 4860 4 4 23,300 26 900 48 72 "Xh Forest floor Surface soil Surface soil Ratio 18,800 5 — 3750 4 4 — — 13,400 19 — 710 135 98 — — “C3 Forest floor Forest floor Surface-soil Surface soil Surface soil 572 41,200 2 2 —~ 4 454 4 454 662 1020 22 49 — 72 251 72 251 Surface soil Ratio. Ratio 286 20,500 * Parts per million x [0-4 = per cent. 30 82 Average ratiof Spring ppm days 1964 2800 37,200 0 — 78 78 38,200 4721 8 133 133 2200 — _— —_ — —_ —_ —_ 99 8 ! 12-99 133 133 133 848 16,400 0 2080 0 78 290 78 320 8650 —_— 27 — th 132 731 320 — . 160 — 8-22 * Partial application to the mineral soi! makes direct comparisons invalid for 1964 data. & Fall ppm days 320-790 — =«132 132