FERTILIZING STRAWBERRIES 



100 pounds of potash. Compare this with the estimated 

 amount of plant food removed by a crop in a period of 

 three years and see how totally inadequate it is to supply 

 its plant food needs. 



UNAIDED SOIL CANNOT SUPPLY ALL NEEDED 

 PLANT FOOD 



Some will argue that the soil will yield up a large quantity 

 of the mineral elements needed. While this depends much 

 on its natural fertility, not over .25% of the total potash 

 supply and 1% of the phosphoric acid contained to a depth 

 of 18 to 24 inches will, according to the best authorities, 

 become available to the growing crop, and this will only 

 take place under the most favorable conditions of culture 

 and management. Supposing a soil, therefore, contains as 

 much as 100,000 pounds of potash, 250 pounds of this element 

 might possibly become available in addition to that furnished 

 by the manure. This would only supply 350 pounds per 

 acre, where a conservative estimate says 375 pounds would 

 be required. All authorities agree that not over 70% to 

 80% of the elements supplied to the soil in commercial form 

 are assimilated, and it is likewise known that there is a con- 

 siderable loss of plant food from all soils of a loose, mechanical 

 character through leaching. These facts a-re presented to 

 convince the doubtful planter that the idea of supplying min- 

 eral commercial fertilizer in adequate quantity to his straw- 

 berry patch is not based on theory alone, but on the discoveries 



15 



