514 



Influence of Manures on Humus 



In pasteurising cream at temperatures above i6o° there is 

 probably some danger of giving to the butter a "cooked 

 flavour, " which Prof. Dean has not experienced on any 

 butter made from milk pasteurised within the range 

 mentioned above. 



The skim-milk is also in better condition to return to the 

 farm after pasteurisation, especially if it is heated and then 

 cooled below 6o° before leaving the creamery. 



Influence of Manures on the Humus of the Soil. 



The United States " Experiment Station Record " (Vol. 

 XIII., No. 4) contains an abstract of an article, published in the 

 " Proceedings of th e Society for the Promotion of Agricultural 

 .Science," on the subject of the effect of various manures upon 

 the proportion of humus in the soil. Reference is made to the 

 importance and functions of humus in the soil in general, 

 and to a series of chemical examinations of soils from plots at 

 the Pennsylvania Experimental Station, which have been 

 used since 1881 for the following manurial experiments: (r) 

 Cropping without manure, (2) manuring with stable manure 

 and Jime, (3) treating with lime alone, (4) treating with 

 crushed limestone, (5) receiving complete mineral fertiliser 

 containing nitrate of soda, and (6) receiving complete mineral 

 fertiliser containing sulphate of ammonia. The chemical 

 examinations made involved determination of (1) loss on 

 ignition, (2) organic carbon, and (3) active humus; besides 

 hygroscopic moisture, nitrogen and hydrogen. 



The results reported show that continuous cultivation on 

 the limestone clay soils used in these experiments has not 

 greatly diminished the amount of humus. The greatest 

 increase in humus was found in the case of the manuring 

 with farmyard manure and lime, although the amount of 

 humus was but slightly smaller in the case of a complete 

 mineral fertiliser, a larger amount of nitrogen being found in 

 the case of a complete mineral fertiliser containing sulphate 

 of ammonia than in the case of that containing nitrate of 

 soda. An examination with litmus paper showed that the 

 limed soil was strongly alkaline, that receiving mineral 



