APPENDIX 349 



shown decided improvement due to a rotation of corn, po- 

 tatoes, wheat, timothy and clover. Stable manure is plowed 

 under for the corn crop, which puts the soil and the manure in 

 prime condition for the potatoes to follow. The potatoes are 

 heavily dressed with commercial fertilizer, which so increases 

 the yield and quality that the potatoes pay a handsome profit 

 above cost of fertilizer. No manuring of any kind is done for 

 the succeeding crops of wheat, timothy and clover. If, instead 

 of using 1500 pounds of fertilizer on the pistatoes, these farmers 

 should use 500 pounds on the potatoes, 500 on the wheat and 

 500 on the grass, their bills would be as high as now, the 

 labor three times as great, and their croijs of potatoes cut 

 down nearly one-half, with but a small increase in grain and 

 hay. It is because p.otatoes are a money crop of the farm that 

 they are fed on the choicest food. The corn plant is the 

 key-keeper of the rotation. Clover supplies the crude ma- 

 terial and corn manufactures^ it into suitable humus for the 

 potato plant, yielding its grain as almost clear gain. On a 

 rotation of this kind, corn is quite as important as the clover, 

 because of its ability as a weed cleaner, and also because 

 stable manure should first be 'strained through a crop of corn' 

 before being used on potatoes." 



As H. W. Collingwood points out, "one great advantage of 

 this system is, that all the farm manure is used on the corn 

 instead of on wheat or other crops." The hot summer is par- 

 ticularly favorable for the action of the chemical [and bac- 

 teriological! processes of the soil, including nitrification 

 (changing of inert nitrogen into active nitrate or amrnonia), 

 and in converting farm manure and all coarse materials in 

 the soil into available plant food. Corn, during its long sum- 

 mer growth, can freely use manurial supplies. Not so with 

 wheat, for its growth stops soon after the corn crop has 

 fairly started growing." 



