1164 



EAELE V. HARDENBURG 



yields obtained in the group listed as not using a cover crop may have been 

 produced on farms which used a cover crop two or three years previously 

 or on farms whose soil was naturally higher in organic content. Granting 

 v this, the data on cover crops for Long Island are not sufficient to indicate 

 either advantage or disadvantage accruing from its use. It is true that 

 in 1912 growers who had not sown a cover crop the previous fall did not 

 attempt to supplement the soil fertility by using more fertilizer. This 

 in itself may indicate that, in the main, only those growers who actually 

 needed the cover crop to maintain yields were the ones who used it. 



The rotations followed in Steuben County, consisting usually of potatoes, 

 grain, and hay, vary principally in the number of successive years that 

 the hay and the grain are left on the same ground. Commercial fertilizer 

 is applied lightly at the time of planting potatoes, and, altho what stable 

 manure is available is put on the sod to be plowed for potatoes, there 

 is seldom enough to cover the entire potato acreage. The yields of hay are 

 largely dependent on the residual fertilizer left from that applied directly to 

 the grain crops. Thus in the longer rotations, in which sod is left down for 

 three or more years, only a poor supply of root and stubble residue is left 

 to supply humus to the potato crop. A comparison of the influence on 

 the yield of various types of rotations in this region is shown in table 7: 



TABLE 7. RELATION OF ROTATION TO YIELD ON 240 STEUBEN COUNTY FARMS IN 1912 



Eliminating the factors of seed and fertilizer as given in table 7, the yield 

 consistently decreased with each successive year that the sod remained in 

 rotation. This shows the tendency of the seeding to become thinner and of 

 less value as a source of humus for the potato crop, the older it becomes. 

 The figures for the last two rotations in the table which differ from the 

 first three in that they contain two years of grain instead of one, and from 



