Aug. 28. 1916 Effect on Plant Growth of Sodium Salts 



865 



Table IV. — Results of experiment 4 (1914), giving the effect of sodium bicarbonate on 

 the germination and growth of wheat 



Series No. 



3 



A 



5 

 6 



7 



Sodium bicar- 

 bouate. 



Added 

 to soil. 



Per ci. 

 O 



•OS 

 . 10 

 . 20 



•3° 

 .40 

 .60 



Recov- 

 ered 



from soil. 



Per cl. 



OI2 

 029 

 071 

 088 

 071 



Sodium 



car- 

 borate 

 recov- 

 ered 

 from 

 soil. 



. 021 



.074 



De- 

 crease 

 in yield 

 from 

 check 

 pots. 



Per ct. 

 O 



6.8 



10.8 



9.2 



59-5 

 9i-5 

 100 



§60 



to. so 



I 



I 

 W-20 



%os 



^■00 



/ 



^ 6 7 / 2 3 



Fig. 5. — Diagram of the percentage of sodium bicarbonate added to the soil in experiment 4 (1914), with 

 carbonate and bicarbonate recovered, together with the total green weight of wheat obtained. The solid 

 black line on the left at each series number indicates the percentage of sodium carbonate added to the 

 soil; the line at the right shows the percentage recovered at the end of the experiment. The solid portion 

 of the line shows the carbonate and the hatched portion the bicarbonate. The curve at the right of the 

 figure shows the relative growth of the plants in each series of pots. 



The first noticeable feature of this experiment is the discrepancy 

 between the amount of bicarbonate added to the soil and the amount 

 finally recovered. There was also evidence of a conversion of the bicar- 

 bonate to the carbonate form in the last two series. In this case, as in 

 experiment 2, there was a decrease of growth in series 2, even though 

 no carbonate salt was recoverable at the end of the experiment. 



The data presented in Table IV is shown graphically in figure 5. 



COMPARATIVE TOXICITY OF SODIUM CARBONATE AND SODIUM BICARBO- 

 NATE 



A comparison of experiments 2 and 4, in which the carbonate and 

 bicarbonate salts were used, shows that these two salts have approxi- 

 52172°— 16 3 



