fertilizer control station. 301 



Partial and Complete Fertilizer— The Profitable Quantity 



OF Commercial Fertilizer to Use. 



The two questions to which the second series is devoted are the 

 following : 



(1). The use of partial as compared with complete fertilizers. 



(2). The relative profits lesulting from the use of different 

 quantities of fertilizers. 



Both of these questions are of great importance in farm practice. 



If a failure to supply in commercial manures all the most im- 

 portant elements of plant food is to prove disastrous to the profits 

 of farming, either immediateh" or after a period of j'ears, it is im- 

 portant that the fact should be shown by good evidence. 



The second question is equally important in farm econom}'. It 

 is well known that no arable soil is so poor that it will not furnish a 

 portion of the food necessary for the production of a crop. That 

 which the soil cannot suppl}' the farmer must, but it is good economy 

 not to increase the artificial supply out of proportion to tlie demand. 



There is abundant evidence that from our good soils the natural 

 supply is an important factor in crop production. 



As in the first series, three plots are devoted to the same method 

 of treatment, and the yields given are the averages of three plots 

 in each case. 



The table below gives the kinds and quantities of manures used, 

 and the yields of grain and straw from each method of treatment. 



The seed (oats) was sown and the crop was harvested at the 

 same time as in the first series of plots. 



