than in 1954. Another possible explanati-n would b= the reduced effect of ploving on lovweriny the average Sr?0 evel at root depth in successive vears, The data in Figure 5 indicate that the sampling was surprisingly good, since the only considerable scatter occurs during the snarp soring rise, ‘he monitoring of milk from large dairies apgpears to rrovide a good record of nlant and dairy product activity levels over the ¢roving season for a given ara and also provides a basis for comparison of the activity of plants and dairy vrodu:t: from widely scattered areas, NYOO S6