from the land, making no return to the soil, one or more of the nec- 

 essary plant foods will be reduced so much that the crop produced 

 will be too small to ])ny for the labor of raising it. When a soil has 

 reached this condition it is said to be exliausted. This does not 

 mean that nothing can be grown on the land but that the crop will 

 be too small to be profitable. Some lands will reach this condition 

 much sooner than otliers, since some lands contain a better supply to 

 start with. A\'e cannot make plants out of nothing. We must sooner 

 or later make a return to the soil for the material that has been taken 

 away in the plants. Those materials which it is most frequently 

 necessary to return to the soil have a money value as real as that of 

 the grain that we sell. A bushel of wheat removes from the soil plant 

 food having a money value of 26f cents, and a bushel of corn removes 

 19^ cents' worth. The g]-ain on the average acre of wheat — 13.'! 

 bushels — removes from the soil plant food worth $3.68, and the grain 

 on the average acre of corn — 30.4 bushels — removes plant food worth 

 $6.04. When we recall that Indiana produces an average crop of 37,- 

 000,000 bushels of wheat and 109,000,000 bushels of corn per year, we 

 see what an enormous drain is being made on the soil, ^'et this re- 

 lates to the grain only. The com stalks, wheat and oat straw remove 

 each year from the soil of the State plant food valued at $•.'«. 000,01 )0. 

 Xot one-half of this is returned to the soil. The loss of $14,0oo,000 

 per year would ])ankrupt any other business than farming. These 

 vast drains on the soil's fertility cannot continue long without reduc- 

 ing the soil to a condition in which it will no longer yield profitable 

 returns. Eotation of efops and improved tillage will not put back 

 all this plant food. Sooner or later we must return plant food to the 

 soil. The sooner we liegin the better, for it is more economical to 

 keep a soil fertile than to restore it after the soil has become impov- 

 erished. 



SOURCES OF PLANT FOOD-MANURES. 



'\^'he^e shall we get our plant food? We may use the same material 

 over and over again. If farm crops are fed and animals and animal 

 products s(.ild over four-fifths of the plant food in the cro|)s may be 

 saved in the form of farmyard manure. These manures being pro- 

 duced from farm crops, have nearly the same relative amount of plant 

 food as the crops removed. But many farmers are not favorably dis- 

 posed to animal production and dairying, and so sell grain. These can 

 at least utilize the side products such as straw and stalks. These 

 coarse materials not only furnish plant food but are of high value in 

 improving the mechanical condition of the soil. 



