
FIELD EXPERIMENTS WITH FERTILIZERS. ber 
In earlier experiments on this field it had been observed that 
yields from some of the plots of the sulphate of ammonia group 
were smaller than those from corresponding plots of the nitrate 
of soda group, the differences being most conspicuous in the 
cases where the largest amounts of the sulphate were used. 
Eyxperiments* elsewhere, however, have given similar results, 
and suggest that the smaller yield with the sulphate of ammo- 
nia may be due to an acid condition of the soil resulting from 
the surplus sulphuric acid left as a residue in the soil after the 
nitrification of the ammonia of the sulphate. In these latter 
experiments air-slacked lime was applied for the purpose of 
neutralizing the acidity, apparently with excellent results. 
Accordingly, in the experiments at the Station in 1898, forty 
pounds of air-slacked lime was applied, in addition to the 
regular fertilizer, on each section in Series A at the north 
end of the field upon which the new lot of seed was planted 
in 1898. On the sections at the south end of the plots (Series 
F), which were planted with corn grown on the same sec- 
tions, the fertilizers were applied without the additional lime. 
A comparison of the yields from the two series, the one with 
and the other without the extra lime, is given in the following 
table. The figures in this table are the averages of the results 
of the experiments of 1898 and 1899 given in Tables 37 and 38 
following. 
Yields of corn and stover from sections treated with lime compared 
wzth ytelds from sections not treated with lime. 









YIELDS PER ACRE. 
| Series F, Series A, 
KIND OF FERTILIZER. | Plot No. | without lime. with lime. 
| asim | Stover. | “Syrac” | Stover. 
bu. lbs. | bu. lbs. 
Nothing, - - - ; O, 00 | 1523 OOF. tetany 1139 
Mixed minerals - - 2 6a, 66 ae Gg 2216 36.6 2047 
7 25.8 2013 35.2 2575 
Nitrate of soda group, 8 42.5 ~ 2480 52.6 3000 
| 9 43:6 2310 52.0 2675 
Vets 39.9 2463 48.6 2938 
Sulphate of ammonia group, _—iII 44.0 2438 48.2 3600 
perede 36.0 1995 51.4 3200 



* For a discussion of the subject of the acidity of soils and the beneficial action of 
lime ae acid soils, see articles by H. J. Wheeler, Ph. D., in the Reports and Bulletins 
of the R. I. Experiment Station. See also U. S. Dept. Agr., Farmers’ Bulletin, No. 77, 
The Liming of Soils, by the same author. 
