1904.] PUBLIC DOCUMENT— No. 33. 115 



ate to six plots, viz., 1, 3, 0, 7, 8 and 11. It is supplied in 

 the forni of lo\v-<^nulc sulfate to four plots, viz., 2, 4, 5 and 

 10. The crops grown in this experiment previous to this 

 year in the order of their succession have been : oats, rye, 

 soy beans, oats, soy beans, oats, soy beans, oats, oats, clover, 

 potatoes, soy beans, i)otatoes. The crop of this year was 

 the medium green soy bean. 



It will be generally understood that, if the object in view 

 in an experiment should be simply the determination of the 

 relative value of different materials applied as sources of 

 nitrogen, such a crop as the soy bean (which belongs to the 

 clover family, and which therefore under the right conditions 

 can draw upon the air for a portion or perhaps for all of its 

 nitrogen) would not be selected ; but we are testing not 

 simply the relative value of the different nitrogen manures, 

 but also the effect of the legume grown on the no-nitrogen 

 plots upon the succeeding crop. Accordingly, the soy bean, 

 which is one of the most successful of the legumes grown as 

 a hoed crop, was our choice, as it has been several other 

 years, during the progress of this expermieut. 



The crop was planted on May 20, and was well cared for 

 throughout the season. N"© accident or inequality in extent 

 of insect or other damage on the several plots interfered with 

 the normal results of the experiment ; but the season was 

 highly unfavorable to the growth of the crop, which is one 

 requiring protracted warm weather. 



Although the yield on the plots to which the nitrate of 

 soda was ai)i)lied was fau'ly satisfactory, attention is here 

 called to the fjict that this fertilizer seems to exert an adverse 

 influence upon the early development of the soy bean. It 

 has been repeatedly noticed that where nitrate of soda is the 

 source of nitrogen, the leaves, especially in the early stages 

 of growth, assume a crinkled or wrinkled appearance, and 

 fail to reach full size and normal development. This crink- 

 ling appears to be due to the death of the marginal tissues 

 of the leaf, and such death is su})posed to be due to an accu- 

 mulation of nitrates in injurious amounts in these tissues. 

 The margin of the leaf ceasing to grow, while its main body 

 still continues to develop, the inevitable consequence is the 



