136 ANNUAL RKPORTS OF Dlii'ARTMENT OF AGRICULTURE. 



soils, and also tends to increase bacterial activity. The maximum 

 number of bacteria was found within the fifth and sixth inches of 

 the soil. An increase in soil temperature was found to increase the 

 activity of the bacteria and an excess of moisture to reduce their 

 number. The IMontana Station observed that where moisture con- 

 tent of the soil w^as good the nitrate formation was relatively high. 

 In connection with these studies it was shown that the great benefit 

 from summer fallow was due to nitrates accumulated in the moist 

 soil during the fallow season, which gives a rapid growth the fol- 

 lowing year, so that the crop usually has advanced beyond the stage 

 of liability to serious injury before the dry period of the year arrives. 



The Utah Station in studying the formation and movement of 

 nitrates in irrigated soils found that the nitric nitrogen tended to 

 accumulate in the lower foot sections during winter and spring. 



In a series of feeding experiments the Nebraska Station demon- 

 strated that when corn is above 35 cents per bushel and alfalfa not 

 over $7 per ton, the old method of fattening cattle for market, which 

 consists of feeding heavily with grain and using little roughage, is 

 much less profitable than a moderate use of grain and correspond- 

 ingly more roughage. In a five-year trial of fattening cattle on blue- 

 gi-ass pasture at the Missouri Station, better gains were made and a 

 more uniform finish was obtained when corn was substituted for 

 either gluten, linseed, or cottonseed meal. 



The Tennessee Station has worked out double cropping systems for 

 the State under which two crops are grown on the land annually, and 

 in that connection has been able to maintain a steer for every acre in 

 this work. 



The North Dakota Station conducted feeding experiments with 

 hogs, in which different feeds were compared. It was found that 

 corn produced a much larger proportion of fat than barley and in 

 consequence made a poorer grade of pork. It required 18 per cent 

 more of barley than of corn to produce a given gain in weight. An- 

 other test showed that gi'ound rejected wheat produced good gains 

 when fed to swine with shorts. In comparison with corn it required 

 8.9 per cent more rejected wheat than corn to produce the same gains^ 

 but the quality of pork produced was better than that produced on 

 corn. 



Several of the stations have shown that heavy feeding of silage — 

 up to over 40 pounds a day — can be follow^ed with axlvantage in fat- 

 tening cattle. In one instance 3 pounds of gain a day were made in 

 this manner, with little grain, and the beef was finely finished. In 

 this connection it is worthy of mention that a number of stations have 

 given considerable attention to silo construction. The Iowa Station 

 has designed a silo built of hollow tile, reenf orced between courses of 



