20 The soils for farms #11 end ,/12 ere not tr vicel for the Chicago 'ilksned area but are coarse sardy soils included in the selection oeeause of their very low celcium level, These tyvo soils sho the lowest 1955 level ard the loresb tye voer jixsrease in available strontium-99, ‘While it is nessivic vicy trey vove.vea Jess Psitst, st 2s uore likelv that sorethince ir the cnenistry of these tus sotis acts to reduce the fraction of "aveileble" strontinun-99. The* toese s ils mey ve ano.slous is further indicated by the unexmectzdly lo conceniration of strontium-90 in the alfalfa zrovm on them (see Table 5 and discussion on pege 22 below). The strontium-90 masurenents “or the tvelve Chicago “ailkshed soils collected in late Sentemzer 1953 have been summarized ard discussed elseviiiere.3 Tne 1953 soils show an averare of sbout 50 nercent of the total evailebie strontiur-% in the top one inch lever for umnlovred soils, en The 1955 ssils show about )CO per- cent of the total available strontium-390 in the ton two inches of unploved soil: Since tris observation applies ecually vell to the seils shoving the lovest total availeble strontium-90 (farms #11 and #12), it appears that the Jeachiiug 0. svrontium-90 to creater dentns oy natural processes is very slo, B. 1955 Chicago NMilkshed Alfalfas Results for the alfalfa sammles are nresented in Table 5 together «ith the results for the soils from which they were collected, The soils are listed in order of decreasinr cencentretion of evailavle calcium in the 0-2" denth surface laver, as snovm in colwnan 2, NYOO The soil levels of availebdle strontium-90 in "Sunshine Units" are listed in the third column torether with the “enth of the soil samrle asseyed. The resvlts for soil samrles of 0-2" dJenth increase fairly regulerly with decreas~ “ny calcium concentration, For the tree rmcently plowed soils, the "Sunshine Unit" values of 0-2" depth are undoubtedly some 2 to 3 times the values given. S,