No. 4.] KEEPING UP FERTILITY. 117 



so as to liolp keep the ammonia in it, and I would like also 

 to keep it trodden down solid, so it would not heat too 

 fast. 



Question. Professor, you know most of these gentlemen 

 here in the old st^de of farming have been accustomed to let 

 the manure remain during the winter and get it out in the 

 spring, and get out only a little at a time before they plough 

 it in, thinking that there would be great loss. Would you 

 advise them to harrow or plough it under immediately, or 

 get it out and spread it, and let it remain until it was con- 

 venient to plough it in ? 



Professor Brooks. That would depend in part upon the 

 manure. There are manures from which there is quite a 

 rapid escape of ammonia. If they were spread out and 

 allowed to remain on the surface, there might be so much 

 loss it would amount to a serious matter. But not every- 

 thing that smells bad is manure ; not always when your 

 dressing has a rank odor does it mean that ammonia is 

 escaping. 



Before this discussion closes perhaps I ought to add just 

 a word. I have taken the ground that " special" fertilizers 

 do not as a rule contain a sufficiently large percentage of 

 potash, while they do contain much more phosphoric acid 

 than would appear to be required. In justice to fertilizer 

 manufacturers it seems only right to say that a fertilizer 

 must not only be made with reference to certain theoretical 

 proportions of the different chemical elements required by 

 plants, but must also be so compounded as to remain in 

 suitable mechanical condition for application. If made with 

 the proportion of potash and phosphoric acid sometimes 

 recommended, a fertilizer would be certain to cake. The 

 excess of phosphate added serves to keep fertilizers dry and 

 to prevent caking, and is in this way useful. It is fur- 

 ther undoubtedly true that some manufiicturers now offer 

 " special" fertilizers much richer in potash than a few years 

 ago; and it is perhaps true, as they claim, that they have 

 complied with the general demand for fertilizers richer in 

 potash to as great an extent as practical and economical 

 conditions allow. Under the existing circumstances, then, 



