Thus the average of seventy-three "Cooperative Fertilizer Tests on Clay and Loam Soils," extending into thirty-eight different counties in Indiana (Bulletin 155), shows 13 cents as the farmer's profit from each dollar spent for "complete" fertilizers used for corn, oats, wheat, timothy, and potatoes, if valued in the field at 40 cents a bushel for corn, 30 cents for oats, 80 cents for wheat, 50 cents for potatoes, and at $10 a ton for hay, over and above the extra expense for harvesting and marketing the increase, and of course the soil grows poorer, because the crops harvested removed much more plant food than the fertilizers supplied. CHAPTER IV PERMANENT SOIL FERTILITY Its Relation to Profits and Future Values THOUGH intelligent soil improvement is the most profitable business in which an honest man can engage, ordinary farming is not a highly remunerative occupation, and to a large extent the fortune of the farmer is bound up with the increase or depreciation in the market value of his land. There are at least three important factors of influence which induce people to continue farming: First, the farmer is his own employer. He controls his own job, is his own boss and has no superior officer to lay him off because of disagreement, dull business or political preferment. Farmers constitute by far the largest class of citizens who own their own business, and are thus "independent." Second, the farmer is able as a rule to make some sort of a living for his family very largely out of the produce of the farm, so that he gets some return for his labor in terms of food, even when there is no profit in farming as a business; whereas the wage-earner of the city, as soon as his wages stop and his savings and credit are exhausted, must see his family supported by charity or starve. This is not fiction, but fact. Third, land is usually considered a safe investment, in which one may hold a perfect and undivided title to his property; and people will retain possession of a farm even when it pays a low rate of interest, rather than sell and invest the proceeds in some other enterprise which they cannot control as individuals or which may suddenly depreciate in earning power, fail or be utterly destroyed. Is Land a Safe Investment?