Commercial and Special Fertilizers. 79 



calculated in pounds per acre, are the following (the plants contained 62.3 

 per cent, of water and the fruit 90 per cent) : 



Composition of the water-free strawberry crop (except roots), at the middle of 

 August, in pounds per acre, according to Pierre: 



Plants. Fruit. 



Organic matter, exclusive of nitrogen .... 4268.4 I0 53-5 



Nitrogen 88.5 16.0 



Silica, iron and manganese oxides 43.3 



Phosphoric acid 35.3 5.4 



Lime 102.7 7-9 



Magnesia 16.1 .7 



Potash 89.1 19.7 



Soda 6.4 .9 



Other matters 1 20.9 8.8 



Dry substance 477-7 1118.2 5888.9" 



These are the constituents that, to start with, must be in the soil, and 

 which must be kept there. This array of what to many are but obscure 

 chemicals need not cause misgivings, since in most instances nature has 

 stored them in the virgin soil in abundant proportions. Even in well-worn, 

 long-cultivated fields, some of them may exist in sufficient quantity. 

 Therefore, buying a special fertilizer is often like carrying coals to New 

 Castle. Useless expenditure may be incurred, also, by supplying some, 

 but not all, of the essential ingredients. A farmer applied 600 Ibs. of 

 superphosphate to a plat of corn-land, and 300 Ibs. to an adjacent plat 

 wherein the conditions were the same. The yield of the first plat was 

 scarcely in excess of that of the second, and in neither case was there a suf- 

 ficient increase to repay for the fertilizer. It does not follow that the man 

 used an adulterated and worthless article. Analysis shows that corn needs 

 nitrogen and potash in large proportions ; and if these had been employed 

 with the superphosphate, the result probably would have been very differ- 

 ent. Superphosphate contains nitrogen, but not in sufficient degree. 

 These considerations bring us to the sound conclusion that in enriching our 

 land it would be wise to use complete fertilizers as far as possible ; that is, 

 manures containing all, or nearly all, the essential ingredients of the straw- 

 berry plant and fruit. If we could always know just what elements are 

 lacking in our soils, we could merely supply these ; but frequent analyses 

 are expensive, and often misleading, at best The safest plan is always to 



