CHEMICAL AND BACTERIOLOGICAL STUDY OF WHEAT SOIL. 105 
case of 50 and 100 mg. additions the total amount of nitrate 
produced was approximately the same, and in one case the 
former gave a larger production of nitrate than 100 mgs. of 
sulphate of ammonia. With the dried blood it is interesting 
to note that in all four cases it yielded the highest amount 
nitrates. As a comparison it may be seen that whereas 
both 100 mgs. (NH,,),SO, and °2 grms. dried blood contain 
apparently 20 mgs. nitrogen, yet the latter accumulates a 
far greater amount of nitrate nitrogen. From this it is 
worth noting that the soil we are dealing with has greater 
capacity for nitrifying dried blood than ammonium sulphate. 
Moreover, being a test of ammonifying power with the 
organic material, the writer would record it as necessary for 
future work on similar lines to include dried blood as one 
medium and 50 mgs. ammonium sulphate as a maximum for 
another. In every case in Table VIII with all amounts of 
medium the fact of variation in nitrifying power between 
the soil in December and March is confirmed. 
There is one other point and a very important one. In 
the February soil samples PB were selected and used fora 
lime test. The soil was treated exactly as in the ordinary 
nitrifying test using 100 mgs. ammonium sulphate but °5 
grms. of CaO and *5 grms. CaCO, were added to different 
lots in addition. It was found that the CaO caused an 
actual loss of nitrate compared to the check soils but the 
CaCO; gave a decided increase. Whereas the soil alone 
nitrified 20°7/ of the ammonium sulphate added, the soil 
+CaCO, nitrified 36°87%. It was this result which brought 
out a suggestion that the soil in situ might be benefited 
both in physical constitution and in nitrifying power by an 
addition of lime. The objections are the expense and 
danger of a dry year, but the writer would maintain that 
an occasional dressing of lime specially in conjunction with 
a green crop would greatly benefit the soil provided a good 
winter fall of rain was obtained. 
