EXPERIMENT STATION BULLETINS. 



367 



FiGUKE 14. — Simpson Farm. Acid phospliate and no treatment. 



FERTILITY REMOVAL AND FARM PROFITS. 



It is highly desirable for a farmer to know what it costs him to pro- 

 duce his various crops. This cost is complicated by many conditions 

 one of which is the removal of plant-food elements from the soil. The 

 question that has been asked us is — "What constitutes a reasonable 

 charge for this loss of fertility?" In replying to this question it must 

 be borne in mind that few if any soils contain the various plant food 

 elements in the same proportion in which they occur in crops. That 

 is to say a soil may contain a sufficient amount of one element to pro- 

 duce several hundred or possibly a thousand maximum crops. An 

 addition of this element may not markedly increase the yield and its 

 use except in small amounts to increase the readily available supply 

 may not be good agricultural practice. It does not appear to be logical 

 to take into account the removal of elements which are present in abund- 

 ance, and which when applied do not increase the yield. Later if the 

 supply of such becomes so depleted that their application to the soil 

 increases the yield it will then be proper to add their cost to the other 

 items. On the other hand there may be so little of a certain element 

 or elements that an application of it or them to the soil in the form of 

 commercial fertilizers materially increases the yield. It is good busi- 

 ness practice to supply the deficient element or elements if it can be' 

 done profitably. 



Potash is present in relative abundance in most of our soils. Many 

 muck and peat deposits are so deficient in it that they soon require its 

 addition in some form in order to produce satisfactory yields as well 



