130 STORRS AGRICULTURAL EXPERIMENT STATION. 



the yields of grain by the increase of the yield per acre obtained 

 on the fertilized sections over the average of the yield from the 

 sections of the two plots not fertilized. 



The yields on the sections of plots o and 00 ^vere of course 

 very light, as these plots have had no fertilizer for the past 

 twelve years. The yields on the sections of plot o were espe- 

 cially light, practically no ears developing; this was probably 

 due in part to the fact that the soil on this plot had washed 

 considerably as a result of severe rains during the previous 

 winter. A similar condition seems to have affected the ^nelds 

 on plot 7, next to plot o. The ground was more sloping on 

 these plots than on most of the others. 



The yields obtained on the sections of plots 6a and 6b, sup- 

 plied with mineral fertilizer (phosphoric acid and potash), were 

 considerably better than those obtained where no fertilizer was 

 used. These plots have not been supplied with nitrogen in the 

 fertilizer since the field was first laid out for experiments in 

 1890. The lack of available nitrogen in the soil caused a pale 

 yellow color in the crop during the season of growth, and re- 

 sulted in a small yield of ears. The growth of stover does not 

 seem to have been much less on these sections than on those 

 where nitrogen was used; but while the yields of stover aver- 

 aged as much as on several of the plots supplied with nitrogen 

 in addition to the minerals, the yields of grain were very much 

 less than on most of the plots having nitrogen. 



The plots supplied with nitrogen were in two groups of three 

 plots each, the successive plots in each group receiving respect- 

 ively 25, 50 and 75 pounds of nitrogen per acre, in addition to 

 the mineral fertilizers which were uniform for all fertilized 

 plots. In one group — plots 7, 8 and 9 — the nitrogen was sup- 

 plied in nitrate of soda, and in the other group^ — plots 10, 11 

 and 12 — in sulphate of ammonia. On both series, A and F, 

 the yields on the sections of plot 7, where the smallest rations 

 of nitrate of soda were used, were quite light, being ver}^ much 

 less than on the corresponding sections of plot 10 where the 

 same quantity of nitrogen was used in the form of sulphate of 

 ammonia. This is perhaps due in part to the fact that the soil 

 on plot 7 was washed, as was pointed out above. On the sec- 

 tions of plots 8 and 1 1 , where 50 pounds of nitrogen per acre 



