26 BULLETIN 218, U. S. DEPARTMENT OF AGRICULTURE. 



Subsoiling and listing show small increases over similar stubble 

 fall plowed. 



The shortness of the record and the inconsistency among the yields 

 make it unsafe to base conclusions on such small differences. 



When cost of production is considered in connection with yields it 

 is seen that the only things that stand clearly by themselves are 

 disked corn ground, with an average profit of $3.39 per acre, and the 

 use of green manure, with a loss of $5.75. The other methods as 

 grouped here show either losses or gains so small as to be subject to 

 changes in their relative positions by a single crop. 



NORTH PLATTE FIELD STATION. 



The work here presented is conducted on the table-land of the 

 North Platte Field Station. The soil is of the type generally known 

 as loess. With the exception of the humus accumulated near the 

 surface, it is practically uniform to great depths. The storage and 

 use of water is unlimited by the depth of the soil or any peculiarities 

 in it. The' development of roots is limited only by the physiological 

 character of the crops grown and the available moisture. It is a 

 soil on which a maximum of results from tillage methods would be 

 expected. 



The North Platte Field Station presents for study the records of 

 eight years. In three of these years the production has been good, 

 in three it has been poor, and in two years the crop has been a 

 failure. 



Spring-plowed wheat stubble has given better results than fall 

 plowing in five of the six years that have produced crops, but the 

 great difference in favor of fall plowing in 1908 reduces the average 

 gain from spring plowing to less than 2 bushels per acre. 



On the plats continuously cropped to oats fall plowing has given 

 better results than spring plowing in four of the six years, the average 

 advantage in favor of it being more than 4 bushels per acre. The 

 spring-plowed plat following oats is the only one in the series that 

 is given shallow plowing. 



Fall plowing oats after oats has been consistently better than after 

 wheat, while with spring plowing the reverse has been the case. 

 The poorest yields have been obtained following alfalfa and brome- 

 grass. These two crops exhaust the available soil moisture and leave 

 the following crop entirely dependent upon seasonal rainfall. Oats 

 following them have usually been the first to suffer from drought. 



Disked corn ground shows about the same average yields of oats 

 as the crop raised after small grains. 



Oats following green manure show a small increase in average 

 yields over all other methods except that of summer tillage. Little 



