CHAPTER XVI 



LIVE-STOCK FARMING 



IF a four-year rotation is practiced, including two crops of corn, 

 followed by oats, with clover seeded the third year, and clover for 

 hay and pasture the fourth year, and all crops used for feed and 

 bedding, the nitrogen balance can be determined by simple com- 

 putations based upon facts established within narrow limits by 

 such data as have been cited in the preceding pages. We may 

 assume 5o-bushel crops of corn and oats, and i^ tons of hay in the 

 first cutting, with i ton additional for all previous and subsequent 

 growth, the same as for the grain system; or here, too, we may 

 double the assumed yields and maintain the same proportions. 

 With the lower yields the three grain crops and the i^ tons of 

 clover hay would contain 256 pounds of nitrogen. Under the 

 most careful system of saving manure, three fourths of this, or 192 

 pounds, can be returned directly to the land, and to this may be 

 added 30 pounds of nitrogen added to the soil in the manure from 

 the one ton of pastured clover, making 222 pounds added by pastur- 

 ing and manuring. If we consider that the nitrogen contained in 

 the clover hay was taken from the air, the real draft upon the soil 

 is only 196 pounds. In this system about 13 per cent more nitro- 

 gen is returned in the manure and pasture than is removed from 

 the soil by the three grain crops. 



If the rotation is extended to five years by sowing clover and 

 timothy and pasturing the fifth year, assuming the growth to be 

 three fourths clover the fourth year and the pasture herbage to 

 be only one fourth clover the fifth year, the outcome with respect 

 to nitrogen would be 256 pounds removed from the soil and 267 

 pounds returned in the manure and pasture droppings during the 

 five years, if we disregard the strong probability that timothy, 

 growing as a companion crop, secures some portion of its nitrogen 

 from the decaying tubercles of the clover roots. 



231 



