AMERICAN INSTITUTE. 425 



The plan now adopted by farmers is to cultivate blindly, not 

 knowing either the requirements of the soil or seeds, which is 

 pursued until their farms are rendered so sterile by carrying off 

 crops annually, without making any returns, that finally weeds 

 refuse to grow. Land may be brought to this unfortuna'e state 

 sooner by one variety of plant than another; for instance, if the 

 soil has but a small portion of the phosphates in it and a great 

 quantity of the silicates, wheat will ruin it more rapidly than 

 barley, for the reason that a single crop of wheat will remove a 

 larger portion of the phosphates than three crops of barley, and 

 •if there should be but a small portion of lime, barley will not 

 succeed at all. The phosphates may be retained in a soil by a 

 proper rotation of crops. If w.^ grow plants that are not intended 

 to go to seed they will require no phosphate, and will therefore 

 leave the soil in an admirable condition to grow a crop of wheat. 

 It is for the want of such cultivation as this that large portions 

 of Virginia, North Carolina and Maryland, once remarkably 

 fertile, have become unproductive to such an extent that vast 

 tracts have been doomed to hopeless impoverishment. From 

 €very acre of this land probably 13,000 pounds of enriching sub- 

 stances have been removed, in the course of a century, in the 

 shape of leaves, tobacco stems, roots, etc., and nothing returned. 

 The roots alone would have preserved it. 



Thousands of acres in our own state might produce admirable 

 crops, if their owners would analize the earth and add the 

 missing requisite, which, nine times out of ten, would be found 

 to be lime, phosphate of lime or potash. I have, by the applica- 

 tion of one of these substances, produced sixty bushels of oats to 

 the acre on a soil considered worn out. Grazing animals take a 

 very large percentage of phosphate of lime, which may be returned 

 in the form of ground bones. The most valuable of all manures 

 are the excrements of men and animals, as they consume oxygen, 

 nitrogen, hydrogen, carbon and sulphur, together with mineral 

 ingredients, A man consumes annually a larger weight of food 

 than his body would weigh, and probably animals do the same. 

 The food and oxygen form combustion in our bodies, similar to 

 the burning of hydrogen and carbon by fire heat. These are 

 expelled through the pores of the skin in the shape of carbonic 

 acid, and the nitrogen forms urea. So animal heat is generated, 

 and our vitality sustained until old age comes upon us, when our 

 body decreases, as more matter leaves it than enters it. 



It is the business of the farmer to find out what proportion of 

 the valuable ingredients of his soil are removed by his animals, 



