In another case, where accurate accounts of the products were kept, 

 the good effects of subsoihng were seen for five successive years after the 

 operation. 



In this country, Sanborn plowed two plots of land, each of ,',, acre, 

 seven inches deep, and then subsoiled one of them to a depth of nine 

 inches more, so that this plot was stirred to a depth of sixteen inches in 

 all. After a severe drouth, he drove- gas-pipes into the earth so that 

 samples of the soil could be taken up from both plots to a depth of fifteen 

 inches. In the earth from the subsoiled plot he found 10.1 per cent of 

 moisture, while in that from the other plot there was only 8.3 per cent. 

 The subsoiled plot yielded corn at the rate of seventy bushels to the 

 acre, and the other plot yielded only forty-nine bushels to the acre." 



Caution 



Do not use the subsoil plow in clay saturated with water; or when 

 the subsoil is sand or gi-avel. 



In thin soil, when a hard-pan lies immediately on top of the loose 

 sand or gravel, the subsoil plow should not be used, for the reason that 

 it would permit water to percolate beyond the reach of the plant roots. 



THE FARM TRACTOR 



THE evolution of farm power in the United States has been con- 

 sistent and progressive ; there has been no halting, no turning back. 



Many years ago the writer was content to plow, harrow, haul and run 

 the treadmill with oxen. The motive power was slow, but sure. As 

 progi'ess quickened, the faithful ox disappeared from the fields; he had 

 served his purpose. The horse displaced the ox, and for many years has 

 been the main motive power upon the farm and highway. With the 

 advent and development of farm machinery, the wave of progress ad- 

 vanced because the horse was more efficient than the ox. The horse 

 pulled implements and wagons, and he turned the big bull wheel of the 

 horse-power that propelled the first combined grain thresher and 

 separator. The process was laborious and slow. The bull wheel and 

 the sweeps became obsolete when the steam engine came, and from the 

 steam engine was developed the first tractor. 



When the pioneers undertook the task of converting the great north- 

 western prairies into wheat fields, steam tractors pulled the plows. They 

 were cumbersome, expensive, and the cost of maintenance was great. 

 They did, however, hasten development, and in that served a good pur- 

 pose. 



The mammoth gas tractors pulling from ten to fourteen plows came 

 on the scene in the nineties. The initial cost was great and the upkeep 



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