InflucMK'c of Plants upon Microorganisms 257 



Tmim-; j(>. Im'li kncic ok Dkvelopmknt ok IIkmiku Plants ui'ov Am noanck 

 OF Radiobactvr (froiii Sfarkey) 



Number of Radiobacter, thousands per gram of soil 



Avcrafie 



U 6.'5 8G MIH 17;5 of All 



ri:iiit D.iys l);iys Days Days Days I'nidils 



Fallow 540 [h>{) !)()() ;{-2() 4'->0 (!2() 



Oals 780 7,800 (J.S'iO 8G0 ()70 ;5,'->90 



(nrn ()80 2,0^>0 .'{,180 .'5,340 IHIO ^2,040 



Hcaiis 1,980 2,540 4,400 360 l,(i40 2,180 



rotatoes 780 980 5,340 1,200 500 1,760 



Table beets 840 1,540 3,560 2,180 1,380 1,900 



Mangel beets 1,400 6,400 3,160 4,000 1,400 3,270 



Rape 46.600 8,600 6,360 5,120 3,640 14,060 



Sweet clover * 1 . 1 40 2 , 000 1 , 900 620 2 , 820 1 , 700 



* For the sweet elover, the sampling periods were 25, 44, 67, 119, and 154 days. 



rapid oxidation in a soil in which plants were growing than in the 

 corresponding nncropped soil kept under the same conditions of 

 moisture, aeration, and temperature. The growing roots exerted a 

 direct influence upon the decomposition of the organic matter in the 

 soil. This also brought about a greater liberation of available plant 

 nutrients and thus stimulated further plant growth. Neller suggested 

 that a symbiotic relationship exists between the growing plant and 

 the oxidizing organisms in the soil. The influence of nature of crop 

 upon the numbers of bacteria and evolution of COi> from soil is 

 illustrated in Table 57. 



Table 57. Lnfluexce of Plant upon the Numbers of Bacterta and 

 Evolution of COo (from Neller) 



According to Starkey, the evohition of CO^ is greater from soils 

 in which plants are growing than in unplanted soil. The course of 



