58 INDIAN CORN CULTURE. 
CHAPTER sv: 
MANURES AND FERTILIZERS. 
It is a generally recognized fact that to re- 
move a crop from the soil is to take from it a 
certain amount of fertility or plant food. If 
this practice is continued without returning 
this food in some form to the soil it becomes 
much impoverished and less and less produc- 
tive. 
Fertilizers necessary.—A crop of 50 bushels 
of Indian corn and 8,000 Ibs. of cornstalks per 
acre will remove from the soil 79.8 lbs. nitro- 
gen, 55.2 lbs. phosphoric acid and 87.6 Ibs. 
potash.* To remove such a crop is a heavy 
drain on the soil fertility, and to purchase in 
the markets the amounts of nitrogen, phos- 
phorie acid and potash removed by it would 
cost about $20. In the great corn-growing 
region of the country, however, a large amount 
of land is annually planted which contains so 
much available plant food that the farmer, 
does not feel justified in placing artificial ferti- 
*Science in Farming, 1882, p. 153. 
