44 BOTANICAL GAZETTE [SEPTEMBER 
under. Clover was also grown on the check part of the field. Very 
little grew here, however, and so there was not much to plow 
under. Mr. MANN stated that the amount of phosphorus applied 
to the land where samples 11 and 12 were taken would just about 
equal that naturally present in the soil, so that these samples would 
be expected to contain about twice the phosphorus of the samples 
from the check portion. Table V shows this to be the case, 
but the sulphur content of the surface soil of the fertilized land is 
also double that of the check portion. This is rather to be expected, 
when we compare the two in their organic matter content. Sample 
11 is about double that of sample 13, and a high organic matter 
content usually means a high sulphur content. The question, 
however, is as to the source of supply of the sulphur. No sulphur 
fertilizers have been applied to the land. There is the possibility 
that, since the clover plant makes considerable growth during the 
time of the heavy rains of the spring and again in the fall after 
the rains start (times when the sulphur content of rainwater is 
rather high), some of the sulphur might come from this source. 
It is not believed, however, that the sulphur brought to the land 
by the rain results in a net increase in the sulphur content of the 
soil, on account of the large amount of sulphur lost in drainage, 
although the amount lost in drainage is greatly decreased when 
the land is covered by a crop. There is the additional possibility 
that the clover roots bring up sulphur from the subsoil, depositing 
it in the surface layers. As shown by the data, the subsoil of the 
fertilized part of the field has about the same sulphur content as 
the soil and subsoil of the check portion. Some of the other soil 
analyses have shown that the sulphur content of various parts of 
the same field may vary widely, when all parts of the field have 
been treated alike so far as sulphur fertilization is concerned. If 
this is true in the present case, then the difference in the sulphur 
content of the two parts of the field would not be significant, but 
the high organic matter content of the fertilized part of the field 
would seem to indicate that these samples are representative, and 
that there really is here a high sulphur content. 
Considering all the samples of table V, it may be said in sum- 
mary that the sulphur content on the average is not high in amount, 
cs 
