90 BOARD OF AGRICULTURE. 



point out the reason, or aid in remedying the difficulty ? I 

 think it can ; and in order to understand the matter it is nec- 

 essary to understand the kind and amount of food which the 

 potato demands. A field of potatoes yielding three hundred 

 bushels to the acre will remove from the soil in tubers and tops 

 at least four hundred pounds of potash ; also it will remove 

 one hundred and fifty pounds of phosphoric acid. Now these 

 amounts are very large, and show that the potato plant is a 

 great consumer of the two substances, and also show that in 

 order to restore our potato fields to their former productive 

 condition, we must supply phosphatic compounds and substances 

 holding potash in large quantities. For six or eight generations 

 in New England our fathers have been exhausting the soil, by 

 removing these agents in their potato and other crops, and we 

 have reached a time when the vegetable is starving in our 

 fields for want of its proper food. Our farmers have found 

 that new land gives the best crops, and this is due to the fact 

 that such fields afford the most potash. But so long as we crop 

 our pastures so unreasonably, we cannot resort to new land, as 

 land is not new that has had its potash and phosphatic elements 

 removed by grazing animals. A potato field which gives but 

 one hundred bushels to the acre requires at least one hundred 

 and forty pounds of potash, but by allowing the tops to decay 

 upon the field, sixty pounds are restored to the soil again, as 

 that amount is contained in them. A medium crop of potatoes 

 requires twice as much phosphoric acid as a medium crop of 

 wheat, so that in two years with wheat the land is deprived of 

 no more of the agent than it loses in one year with potatoes. 



The aim has been in what has been said, to point out the 

 nature of the materials which plants require, and to impress 

 upon the minds of soil cultivators the great truth that, when 

 they have gained this knowledge, and also learned the quantity 

 necessary for a given crop, the accumulation and use of these 

 materials are as simple as supplying raw materials for making 

 cloth, boots and shoes, or any other manufacture. A field in 

 proper condition for culture should contain, in ample abundance, 

 all the inorganic materials which the intended crop requires, 

 and these materials should be in an assimilable condition, or in 

 other words, they should be in a soluble condition, so that by 

 the aid of water they can be taken up and carried through the 



