NITROGEN, PHOSPHORIC ACID AND POTASH. 91 



plant organism. The proper manures for wheat and corn are 

 the nitrogenized varieties, or those which hold nitrogen, either 

 in the form of ammonia, or as nitric acid. These should be 

 conjoined with phosphates and potash in considerable amounts. 

 For potatoes, potash, phosphates and lime are required ; the 

 latter element, lime, enters largely into the leaves, and is an 

 important article of food for the vegetable. Gypsum, or plas- 

 ter, which holds lime and sulphurous acid, is a valuable 

 manurial agent for potatoes, especially on moist land. Enough 

 has been said to show that each variety of plants demands 

 peculiar kinds of food, and unless this is supplied by the soil, 

 or through our agency, it is impossible for them to flourish. 



The sources of supply of food adapted to the wants of plants, 

 are, for the most part, well understood ; still, it may be desirable 

 to devote a few moments to the consideration of this most 

 important subject. We must constantly bear in mind, that 

 there are but three substances consumed by plants which bear 

 a high commercial value, or which, in other words, are of a 

 costly nature. These are nitrogen, phosphoric acid, and 

 potash. The soda, iron, lime, <fcc , are not substances which, 

 in the amounts demanded, should receive much consideration 

 in estimating the cost of fertilizing material. They are essen- 

 tial, but the soil supplies them usually in sufficient quantities, 

 and when this is not the case, they can be furnished quite 

 cheaply. Animal excrement holds all the substances which 

 plants require in an assimilable condition, and if enough was 

 furnished to meet the wants of agriculture, we should have no 

 occasion to seek for plant-food in other directions. It is best 

 for the farmer to bend every effort to increase his supplies of 

 excrement, and to utilize every pound of excrementitious 

 material from house, barn and stable. It is presumed that all 

 sensible, thrifty farmers do this ; and still the want of further 

 supplies of plant-food is most decidedty felt, and anxious 

 inquiries are made as to how the want may be met. I presume 

 it is well known to many of those whom I have the honor to 

 address, that during the past nine years I have endeavored, by 

 extended experiment on a farm, in Essex County, to show that 

 fields can be fertilized and sustained in good tilth by the use of 

 the agents holding* plant-food, excluding animal manures 

 altogether. In addresses at former meetings of the State Board, 



