NEw YorkK AGRICULTURAL EXPERIMENT STATION. 323 
ammonia. With the sulphate of ammonia the results were very 
variable. 
Dried blood, combined with the smaller percentage of manure, 
gave, in the aggregate, better results than either nitrate of soda 
or sulphate of ammonia similarly combined. 
The best crops were grown where the soil was fertilized with 
stable manure. 
Those portions of soils which received applications of 5 per ct. 
of manure in combination with the commercial fertilizers always 
showed a very great increase in yield over corresponding soils which 
were treated only with the commercial fertilizers. Further in- 
crease in the manure, however, was not followed by a correspond- 
ing increase in the yield. 
When soils similar to those under test are used for the first time 
for forcing a crop of lettuce, much more manure may doubtless be 
used with profit than would be profitable where manure has been 
used abundantly with previous crops. 
Where the use of manure is continued year after year on soil 
originally not rich enough to force good lettuce the optimum 
amount may be expected to decline first toward 10 per ct., event- 
ually to approach 5 per ct. 
The amount of manure which may be used with good economy 
in forcing lettuce varies with the character of the soil and of the 
manure, and also with the differences in prices received for fancy 
lettuce and ordinary lettuce. For these reasons no definite amount 
can be recommended. 
Repeated applications of excessive quantities of manure to the 
same soil are not good economy. Manure is thus wasted and the 
yield may be reduced. 
Where large amounts of manure were incorporated in the soil 
for forcing lettuce the yield was increased by compacting the soil. 
This shows that unfavorable effects which follow excessive appli- 
cations of manure may be caused, in part at least, by thereby loosen- 
ing the soil so much as to put it in an unfavorable mechanical con- 
dition for the lettuce plant. 
The clay loam used in these experiments has always proved 
superior to the light sandy loam for forcing lettuce when both 
were fertilized with equal amounts of stable manure. 
While these results apply directly only to the forcing of lettuce 
it is probable that they may be used in a general way in the grow- 
ing of all crops where the leaves are the edible portion; and it 
has been proved both by other experiments at this Station and 
