Apr. 3. 1916 Relation of Carbon Bisulphid to Plant Growth 7 



amount of soluble nitrogen as ammonia or nitrate, then corn and mustard 

 should behave much alike. The nitrogen-feeding power of these plants 

 has been studied by Kriiger (8), Gerlach and Vogel (3), and others. It 

 is supposed that both corn and mustard are heavy nitrogen-feeding 

 crops, able to take nitrogen either in the form of ammonia or nitrate. 



BUCKWHEAT, CORN, AND OATS IN MIAMI SII.T LOAM 



In order to decrease the factor of individual variation, four parallel 

 jars of Miami silt loam were used in each series in the following experi- 

 ment. For the second crop these were subdivided into sets of two 

 each. After the first crop was harvested, the soil and roots were thor- 

 oughly mixed and the jars replanted. The rotation was as follows: 

 First crop, buckwheat; second crops, corn and mustard; first crop, com; 

 second crop, buckwheat; first crop, oats; second crops, com and mus- 

 tard. In Tables V, VI, and VII are presented the results of these 

 experiments. 



TabIyE V. — Effect of carbon bisulphid on the growth of buckwheat and corn 



No. 



SoU. 



Carbon 



bisulphid 



added. 



Per cent. 



Control. 

 Control. 

 Control. 

 Control. 



W eight of first crop, buckwheat. Weight of second crop , com 



Gm. 

 90 



97 

 121 

 126 

 124 



145 

 127 

 126 



Dry. 



Average. Green 



Gm. 



19 



24- 5 



Gift, 



152 

 160 



169 

 136 



Dry. 



Gm. 



28. 5 



33-5 



34 

 31-5 



Average. 



Gm. 



32.7 



The yields of buckwheat and corn are given in Table V. The weights 

 of the mustard were lost. Buckwheat gave an increase in the treated 

 soil, while corn (the second crop) did not show any improvement. Deter- 

 minations of ammonia present at the time the buckwheat was cut (three 

 months after treatment) resulted as follows: Ammonia — if control is 100, 

 then carbon bisulphid treated is 192. Nitrate — if control is 100, then 

 carbon bisulphid treated is 28. The antiseptic increases ammonia, but 

 decreases the nitrate content of soil. The results of investigation show 

 that buckwheat feeds largely on nitrate nitrogen (9), while com is sup- 

 posed to be able to take its nitrogen in the form of ammonia. A difference 

 in nitrogen-feeding power can not be used to explain the unequal behavior 

 of these plants toward carbon bisulphid. Although the weights of the 

 mustard crop were not kept, the action of the carbon bisulphid was 

 evident. There was a decided gain in the growth of plants in the treated 

 series. 



From the data of Table VI it is obvious that carbon bisulphid has very 

 little effect on corn (first crop) or buckwheat (second crop). 



