FIELD EXPERIMENTS WITH FERTILIZERS. 131 



was used, there was quite a marked increase in the yields, 

 whether the nitrogen was suppHed in nitrate of soda or in sul- 

 phate of ammonia. As in the case of plots 7 and 10, however, 

 the largest yield was again from the sections with the sulphate 

 of ammonia; this unusual condition may possibly be due to the 

 wetness of the season, resulting in a greater leaching and loss 

 of the nitrate than of the sulphate. On the sections of plots 9 

 and 12, where the largest rations of nitrogen were used, the 

 yields of grain were, with one exception, the largest of those 

 on any of the sections. The gradual increase in yields corre- 

 sponding to the amounts of nitrogen used points out the import- 

 ance of this element in the growth of corn. It is of interest to 

 note, however, that the yields were everywhere less than on 

 the corresponding sections in 1900. This was probably due to 

 the character of the season in 1901, the exceptionally heavy 

 rains which characterized it probabl}^ favoring the leaching out 

 of the more soluble fertilizing ingredients, especially the nitro- 

 gen, while in 1900 the season was drier and the storms were 

 not generally characterized by heavy rainfalls. However, the 

 yields obtained in the experiments of the later years are in 

 general smaller than those of earlier years. This difference 

 may be due in part to the absence of organic matter in the soil 

 which when present would tend to retain the nitrogen until 

 the crop could use it. This lack of organic matter is suggested 

 by the fact that for twelve j-ears the soil has been supplied 

 with chemical fertilizer only, and as very little organic matter 

 was supplied the amount previously in the soil has probably 

 been graduall};' redviced as the period of the experiment was 

 extended. 



Comparison of yields from sediojts with and tvithoiit lime. — 

 From the results in Table 66 it will be observed that while the 

 3'ields from sections F of plots 10 and 11, with the small and 

 medium amounts of nitrogen in sulphate of ammonia, were 

 considerably greater than those from the corresponding sec- 

 tions of plots 7 and 8 with the same quantities of nitrogen in 

 nitrate of soda, the yield from section F of plot 12 with the 

 large amount of nitrogen in sulphate of ammonia was con- 

 siderably less than that from section F of plot 9 with the same 

 amount of nitrogen in nitrate of soda. Inasmuch as the two 



