1916.1 PUBLIC DOCUMENT — No. 31. 27a 



INVESTIGATION. 



The department reports which follow present a general de- 

 scription of the principal experimental work in each, and to 

 these reports reference should be made for detailed information. 



Department of Agriculture. 



The lines of work followed in the agricultural department are 

 mainly concerned with investigations concerning the relations of 

 varied use of fertilizers, manures and various fertilizer materials 

 and lime to the productive capacity of soils with different crops. 

 Our main lines of investigation have been continued during the 

 past year, but are being more and more closely correlated with 

 chemical investigations conducted by Professor Morse and his 

 assistants. The outcome of the work in progress is a constantly 

 increasing knowledge of the conditions affecting productive 

 capacity. One line of investigation which has been followed for 

 some twenty-six or twenty-seven years indicates so decisively 

 and so consistently throughout this long series of years that the 

 use of lime has not increased the availability of the soil potash 

 that we have had no hesitation in advising against dependence 

 upon lime, during this period when potash cannot be purchased, 

 as a means of bringing soil potash within the reach of the crop. 

 The report of the agriculturist calls attention to a few only of 

 the lines of investigation in progress. 



The report upon the results of the season on Field A, devoted 

 to a comparison of different materials as sources of nitrogen, is 

 of particular interest as it shows so clearly how important it is 

 to consider the effect of residual material in estimating the 

 relative value of such nitrogen fertilizers as nitrate of soda and 

 sulfate of ammonia. It has been found that even without ap- 

 plication of lime, splendid crops of clover can be produced where 

 nitrate of soda as a source of nitrogen has been continuously 

 used for twenty-six years. On the other hand, where sulfate of 

 ammonia has been regularly applied, clover is a practical failure 

 unless lime be applied in large quantities. Another point very 

 strikingly brought out by the results of the year is the possi- 



