6 BULLETIN 108, tT. S. DEPARTMENT OF AGRICULTURE. 



reduced from 100 to 77, or 23 per cent. With 50 parts per million 

 the growth was reduced from 100 to 61, or 39 per cent. In amounts of 

 100 and 200 parts per million the plants were killed. 



EFFECT ON CORN. 



The action of salicylic aldehyde in soil and also in sand was tested 

 as to its effect on corn. The aldehyde was added to a clay soil and 

 to pure quartz sand in amounts of 50 parts per million. One pot 

 each of the soil and sand untreated was run as a check. The corn 

 was planted May 23 and grew until June 20. One corn plant was 

 grown in each pot containing soil and two plants in each pot con- 

 taining sand. 



A photograph of the plants is shown in Plate IV, figure 1. The 

 first two pots contain soil and the last two sand. Number 2 in each 

 case had been treated with salicylic aldehyde. Growth in the treated 

 pots is seen to be much smaller than the growth in the check pots. 

 The effect of the salicylic aldehyde in the sand is seen to be greater 

 than in the clay soil. 



The green weight of the plants was taken at the termination of the 

 experiment. The salicylic aldehyde was found to have reduced 

 growth in the clay soil from 100 to 78, or 24 per cent, and in the sand 

 from 100 to 40, or 60 per cent. The harmful effect was more marked 

 in the quartz sand than in the clay soil, which is jDrobably due to the 

 absorptive power of the clay being far greater than that of the sand, 

 and perhaps also to the higher nutritive value of the soil in compari- 

 son with the pure sand. 



EFFECT ON CLOVER. 



The clover was grown in an ordinary flower pot holding 6 pounds 

 of soil, using a good loam soil, the Hagerstown loam. One pot was 

 untreated, the other had a total of 100 parts per million of the sali- 

 cylic aldehyde added to it. 



When the soil was potted 50 parts per million of the aldehyde was 

 added, and clover then sown, 0.5 gram of seed per pot. Later, when 

 the clover was up, 25 parts per million more of the aldehyde was 

 added in solution through a funnel passing into the soil nearly to the 

 bottom of the pot, thus avoiding direct contact with the tops or roots 

 of the clover. Three weeks later another 25 parts per million was 

 added in the same manner. The experiment lasted from April 12 

 to June 21, 1912. From the beginning the effect of the aldehyde on 

 the clover was noticeable. 



In Plate IV, figure 2, is shown the appearance of the pots when the 

 clover was well up. The inhibiting effect of the salicylic aldehyde 

 is clearly shown. The control was of a deep green color, while the 

 treated pot showed not only a poor growth, but also a much faded 

 color, and had a decidedly unhealthy appearance. 



